HHC 2014 Programming Contest

[Joe Horn]

(09-27-2014 07:44 PM)Don Shepherd Wrote:  I would say Dec 31 to Jan 1 of the following year is out-of-scope and should not be tested.

Actually, it has to be tested for, since a "PDP Date" is defined as any date in a Prime Date Pair, and the program must return all the "PDP Dates" in the given year... even if one of those PDP Dates is Jan 1 or Dec 31. That little complication was an intentional part of this mini-challenge, just for fun.

[Neil Hamilton]

Maybe I am misunderstanding something in the format but it appears that there may be up to 30 entries missing from your table. I get 1057 pairs in the 1583 - 9999 range and you get 1027.

These are the earlier of the 2 dates for the ones that appear to be missing. I hand checked a few (only one shown) to ensure that my program wasn't doing something wacky.

Code:


31.016401 => 64010131 (prime), 64010201 (prime)
31.016422
31.016428
31.016488
31.016527
31.016539
31.016545
31.016548
31.016554
31.016560
31.016581
31.016620
31.016650
31.016653
31.016677
31.036435
31.036549
31.036666
31.036699
31.036768
31.036774
31.036822
31.036831
31.036873
31.037170
31.037209
31.037449
31.037560
31.037608
31.037680

Am I missing something?

Here is my complete list. It took somewhat longer than my estimate to run (10377 s instead of 8400 s) and yielded a few PDPs fewer than my estimate (1057 instead of 1122 +/- 50). Note that, due to the STD formatting on the 50G, the years ending with 0 are truncated -- 0-extend as required.

Code:


# years 1583-9999
31.101586,1.111586
31.081588,1.091588
31.1216,1.011601
31.031608,1.041608
31.011613,1.021613
31.121621,1.011622
31.031629,1.041629
31.031632,1.041632
29.021636,1.031636
31.101652,1.111652
31.071664,1.081664
31.081672,1.091672
31.031674,1.041674
31.081678,1.091678
31.011679,1.021679
31.071679,1.081679
31.101679,1.111679
31.071697,1.081697
31.071706,1.081706
31.101709,1.111709
31.051732,1.061732
31.101733,1.111733
31.121747,1.011748
31.031764,1.041764
31.011769,1.021769
31.011787,1.021787
31.011793,1.021793
31.101793,1.111793
31.071796,1.081796
31.051804,1.061804
31.101805,1.111805
31.12181,1.011811
31.101811,1.111811
31.031824,1.041824
31.121828,1.011829
31.011835,1.021835
31.071841,1.081841
31.071847,1.081847
31.031866,1.041866
31.05187,1.06187
31.051876,1.061876
31.031881,1.041881
31.071886,1.081886
31.121891,1.011892
31.071913,1.081913
31.051921,1.061921
29.021924,1.031924
31.011925,1.021925
31.12193,1.011931
31.03195,1.04195
31.121972,1.011973
31.121978,1.011979
31.011979,1.021979
31.031983,1.041983
31.121987,1.011988
31.08199,1.09199
31.101997,1.111997
31.052002,1.062002
31.082017,1.092017
31.072018,1.082018
31.12202,1.012021
29.022028,1.032028
31.122029,1.01203
31.102036,1.112036
31.032064,1.042064
31.082068,1.092068
31.012075,1.022075
31.05208,1.06208
29.02208,1.03208
31.102081,1.112081
31.072093,1.082093
31.082107,1.092107
31.05211,1.06211
31.052122,1.062122
31.102132,1.112132
31.032136,1.042136
31.012138,1.022138
31.10215,1.11215
31.122161,1.012162
31.012165,1.022165
31.012171,1.022171
31.072204,1.082204
31.032211,1.042211
31.102216,1.112216
31.082242,1.092242
31.052257,1.062257
31.032262,1.042262
31.012264,1.022264
31.082281,1.092281
31.072282,1.082282
31.032289,1.042289
31.08229,1.09229
31.012291,1.022291
31.082302,1.092302
29.022304,1.032304
29.022308,1.032308
31.102312,1.112312
31.072315,1.082315
31.08232,1.09232
31.01233,1.02233
31.052338,1.062338
31.012372,1.022372
31.082374,1.092374
31.122383,1.012384
31.032385,1.042385
31.072396,1.082396
31.082404,1.092404
31.082413,1.092413
31.122413,1.012414
31.102414,1.112414
31.01242,1.02242
31.10242,1.11242
31.052425,1.062425
31.072435,1.082435
31.102435,1.112435
31.122437,1.012438
31.012438,1.022438
31.102444,1.112444
31.082446,1.092446
29.022448,1.032448
31.012456,1.022456
31.052485,1.062485
29.022508,1.032508
31.10251,1.11251
31.032511,1.042511
31.102531,1.112531
31.122533,1.012534
31.032535,1.042535
31.052539,1.062539
31.082539,1.092539
31.07254,1.08254
31.052542,1.062542
31.072561,1.082561
31.10257,1.11257
31.032574,1.042574
31.012576,1.022576
31.122581,1.012582
31.0126,1.0226
31.122602,1.012603
31.082611,1.092611
31.082614,1.092614
31.072615,1.082615
31.082617,1.092617
31.012633,1.022633
31.032634,1.042634
31.12265,1.012651
31.10266,1.11266
31.052674,1.062674
31.05268,1.06268
31.122689,1.01269
31.032706,1.042706
31.052713,1.062713
31.082728,1.092728
31.102729,1.112729
31.052731,1.062731
31.052737,1.062737
31.012765,1.022765
31.122776,1.012777
31.072777,1.082777
31.032781,1.042781
31.072798,1.082798
31.102801,1.112801
31.032802,1.042802
31.032814,1.042814
31.052818,1.062818
31.032829,1.042829
31.102834,1.112834
31.032847,1.042847
31.03285,1.04285
31.102864,1.112864
31.102867,1.112867
31.012876,1.022876
31.052884,1.062884
31.012885,1.022885
31.0129,1.0229
31.072912,1.082912
31.102912,1.112912
31.082926,1.092926
31.102927,1.112927
31.122932,1.012933
31.012933,1.022933
31.03294,1.04294
31.052944,1.062944
31.102945,1.112945
31.072951,1.082951
31.012987,1.022987
31.10299,1.11299
..31.033,1.043
31.073014,1.083014
29.023036,1.033036
31.033039,1.043039
31.013047,1.023047
31.013068,1.023068
31.033072,1.043072
31.083079,1.093079
31.013083,1.023083
31.053085,1.063085
31.123097,1.013098
31.103107,1.113107
31.083109,1.093109
31.033114,1.043114
31.073122,1.083122
29.023124,1.033124
31.073131,1.083131
31.013155,1.023155
31.073155,1.083155
31.033171,1.043171
31.103173,1.113173
31.073176,1.083176
31.033186,1.043186
31.08319,1.09319
31.03321,1.04321
31.073212,1.083212
31.013221,1.023221
31.083223,1.093223
31.053226,1.063226
31.033252,1.043252
31.07326,1.08326
29.023264,1.033264
31.073266,1.083266
31.033267,1.043267
31.053274,1.063274
31.083274,1.093274
31.073278,1.083278
31.033285,1.043285
31.053289,1.063289
31.033297,1.043297
31.123298,1.013299
31.013317,1.023317
31.033327,1.043327
31.083328,1.093328
31.073344,1.083344
31.083346,1.093346
31.033351,1.043351
31.073377,1.083377
31.123379,1.01338
31.053388,1.063388
31.103395,1.113395
31.073398,1.083398
31.103407,1.113407
29.023424,1.033424
31.103428,1.113428
31.08343,1.09343
31.083439,1.093439
31.033441,1.043441
31.10347,1.11347
31.053472,1.063472
31.083475,1.093475
31.03348,1.04348
31.123487,1.013488
31.083508,1.093508
31.053511,1.063511
31.013515,1.023515
31.073521,1.083521
31.123538,1.013539
31.033546,1.043546
31.073554,1.083554
31.033564,1.043564
31.073572,1.083572
31.123574,1.013575
31.103575,1.113575
31.033591,1.043591
31.053598,1.063598
31.073611,1.083611
31.013614,1.023614
31.103632,1.113632
31.033633,1.043633
31.123634,1.013635
31.08364,1.09364
31.033648,1.043648
31.073653,1.083653
31.083661,1.093661
31.08367,1.09367
31.123685,1.013686
31.123688,1.013689
29.023688,1.033688
31.073692,1.083692
31.123694,1.013695
31.07371,1.08371
31.123727,1.013728
31.033747,1.043747
29.023748,1.033748
31.073755,1.083755
31.073758,1.083758
31.053787,1.063787
31.0738,1.0838
31.1038,1.1138
29.023816,1.033816
31.073818,1.083818
29.02382,1.03382
31.033822,1.043822
31.013827,1.023827
31.083853,1.093853
31.033855,1.043855
31.103857,1.113857
31.053862,1.063862
31.053868,1.063868
31.073875,1.083875
31.053877,1.063877
31.083886,1.093886
31.073887,1.083887
31.033894,1.043894
31.103896,1.113896
31.103899,1.113899
31.083901,1.093901
29.023904,1.033904
31.013914,1.023914
31.07392,1.08392
31.013923,1.023923
31.053928,1.063928
31.013929,1.023929
31.103932,1.113932
31.013944,1.023944
31.103995,1.113995
31.124,1.014001
31.074007,1.084007
31.104016,1.114016
31.084024,1.094024
31.074064,1.084064
31.074073,1.084073
31.054084,1.064084
31.104088,1.114088
31.124099,1.0141
31.074118,1.084118
31.054123,1.064123
31.084135,1.094135
31.124141,1.014142
31.05415,1.06415
31.074157,1.084157
31.124162,1.014163
31.084171,1.094171
31.074181,1.084181
31.104181,1.114181
31.124189,1.01419
31.014202,1.024202
31.08421,1.09421
31.01422,1.02422
31.054225,1.064225
31.054231,1.064231
31.084231,1.094231
31.12424,1.014241
31.124246,1.014247
31.124252,1.014253
31.074253,1.084253
31.104262,1.114262
31.014271,1.024271
31.074298,1.084298
31.124306,1.014307
31.07431,1.08431
31.034323,1.044323
31.014328,1.024328
31.104334,1.114334
31.10434,1.11434
31.074349,1.084349
31.014352,1.024352
31.074364,1.084364
31.034365,1.044365
31.034383,1.044383
31.074388,1.084388
31.104394,1.114394
31.054396,1.064396
31.1044,1.1144
31.014409,1.024409
31.054411,1.064411
31.124411,1.014412
31.014415,1.024415
31.054417,1.064417
31.104445,1.114445
31.034449,1.044449
31.054456,1.064456
31.084459,1.094459
29.024464,1.034464
31.034467,1.044467
31.104478,1.114478
31.05448,1.06448
31.104484,1.114484
31.084486,1.094486
31.01449,1.02449
31.034491,1.044491
31.084525,1.094525
31.054528,1.064528
31.084528,1.094528
31.014538,1.024538
31.104559,1.114559
31.084567,1.094567
31.104571,1.114571
31.10458,1.11458
31.054585,1.064585
31.124597,1.014598
31.104598,1.114598
31.034629,1.044629
31.08463,1.09463
31.124642,1.014643
31.074643,1.084643
31.03465,1.04465
31.054663,1.064663
31.054669,1.064669
31.124684,1.014685
31.074685,1.084685
31.054693,1.064693
31.034695,1.044695
31.034701,1.044701
31.034722,1.044722
31.054726,1.064726
31.084732,1.094732
31.034752,1.044752
31.124756,1.014757
31.084765,1.094765
31.104769,1.114769
31.034779,1.044779
31.014781,1.024781
31.01479,1.02479
31.104793,1.114793
31.104796,1.114796
31.104802,1.114802
31.034803,1.044803
31.054807,1.064807
31.124813,1.014814
31.054816,1.064816
31.054834,1.064834
31.034836,1.044836
31.014871,1.024871
31.074871,1.084871
31.054873,1.064873
31.104874,1.114874
31.054876,1.064876
31.034881,1.044881
31.084912,1.094912
31.034914,1.044914
31.084915,1.094915
31.104925,1.114925
31.084927,1.094927
31.104934,1.114934
31.034935,1.044935
29.024936,1.034936
31.054948,1.064948
31.03495,1.04495
31.014979,1.024979
31.12499,1.014991
31.034992,1.044992
31.084996,1.094996
31.124996,1.014997
31.054999,1.064999
..31.015,1.025
31.105003,1.115003
29.025004,1.035004
31.015015,1.025015
29.02502,1.03502
31.125029,1.01503
31.075039,1.085039
31.105039,1.115039
31.055041,1.065041
31.105045,1.115045
31.125053,1.015054
31.035067,1.045067
31.085068,1.095068
31.08508,1.09508
31.035082,1.045082
31.075093,1.085093
31.015096,1.025096
31.125104,1.015105
31.015108,1.025108
31.05511,1.06511
29.025116,1.035116
31.015129,1.025129
31.015132,1.025132
31.075144,1.085144
31.10515,1.11515
31.015153,1.025153
31.085158,1.095158
31.085161,1.095161
29.025196,1.035196
31.035229,1.045229
31.085239,1.095239
29.025244,1.035244
31.075255,1.085255
31.085272,1.095272
31.015273,1.025273
31.075276,1.085276
31.075294,1.085294
31.035298,1.045298
31.055302,1.065302
31.015306,1.025306
31.125326,1.015327
31.015327,1.025327
31.055338,1.065338
31.055359,1.065359
31.085371,1.095371
31.125374,1.015375
31.015375,1.025375
31.015378,1.025378
31.055389,1.065389
31.105396,1.115396
31.075399,1.085399
31.055425,1.065425
31.125428,1.015429
31.105429,1.115429
31.125437,1.015438
31.015441,1.025441
31.085455,1.095455
31.055461,1.065461
31.035469,1.045469
31.085473,1.095473
31.01548,1.02548
31.075483,1.085483
31.105486,1.115486
31.055512,1.065512
31.085524,1.095524
31.015531,1.025531
31.105537,1.115537
31.035541,1.045541
31.125542,1.015543
31.125557,1.015558
29.02556,1.03556
31.01557,1.02557
31.03558,1.04558
31.015582,1.025582
31.085584,1.095584
31.105588,1.115588
31.075603,1.085603
31.035613,1.045613
31.085614,1.095614
29.025616,1.035616
31.105618,1.115618
31.035619,1.045619
31.055635,1.065635
31.075642,1.085642
31.035643,1.045643
31.125647,1.015648
31.08565,1.09565
29.025652,1.035652
31.035655,1.045655
31.035658,1.045658
31.125659,1.01566
29.02568,1.03568
31.105681,1.115681
31.015693,1.025693
31.035709,1.045709
31.125716,1.015717
31.035721,1.045721
31.105726,1.115726
31.075735,1.085735
31.015738,1.025738
31.035745,1.045745
31.085764,1.095764
31.105768,1.115768
31.055776,1.065776
31.055785,1.065785
31.125788,1.015789
31.105804,1.115804
31.125818,1.015819
31.035823,1.045823
31.085839,1.095839
31.01584,1.02584
31.125848,1.015849
31.03585,1.04585
31.085887,1.095887
31.075897,1.085897
31.015909,1.025909
31.075915,1.085915
31.035919,1.045919
31.10593,1.11593
31.125953,1.015954
31.035955,1.045955
31.055956,1.065956
31.055968,1.065968
31.035976,1.045976
31.01599,1.02599
31.085992,1.095992
31.075996,1.085996
31.085998,1.095998
31.036042,1.046042
31.01605,1.02605
31.086058,1.096058
31.086064,1.096064
31.056073,1.066073
31.056082,1.066082
31.106089,1.116089
31.076092,1.086092
31.036099,1.046099
31.056103,1.066103
31.126103,1.016104
31.056112,1.066112
31.076113,1.086113
31.056118,1.066118
29.026124,1.036124
31.076125,1.086125
31.036153,1.046153
31.076158,1.086158
31.076167,1.086167
31.106167,1.116167
31.056181,1.066181
31.126184,1.016185
31.056196,1.066196
31.126196,1.016197
31.016197,1.026197
31.0162,1.0262
31.036201,1.046201
31.016203,1.026203
31.086208,1.096208
31.126208,1.016209
31.086226,1.096226
31.086235,1.096235
31.126235,1.016236
31.106242,1.116242
31.076251,1.086251
31.036255,1.046255
31.076257,1.086257
31.126259,1.01626
31.03627,1.04627
31.036273,1.046273
31.076275,1.086275
31.08628,1.09628
31.106281,1.116281
31.056283,1.066283
31.126298,1.016299
31.016299,1.026299
31.056301,1.066301
31.016314,1.026314
31.016317,1.026317
31.01632,1.02632
31.106326,1.116326
31.056328,1.066328
31.086343,1.096343
31.106353,1.116353
31.086394,1.096394
29.026396,1.036396
31.056397,1.066397
31.016401,1.026401
29.026408,1.036408
31.016422,1.026422
31.086424,1.096424
31.016428,1.026428
31.036435,1.046435
29.026436,1.036436
31.106446,1.116446
31.106452,1.116452
31.076458,1.086458
29.02646,1.03646
31.056475,1.066475
31.076479,1.086479
31.016488,1.026488
31.086526,1.096526
31.016527,1.026527
31.10653,1.11653
31.056532,1.066532
31.126532,1.016533
31.016539,1.026539
31.056541,1.066541
31.126544,1.016545
31.016545,1.026545
31.086547,1.096547
31.016548,1.026548
31.036549,1.046549
31.016554,1.026554
31.01656,1.02656
31.016581,1.026581
31.076599,1.086599
31.056607,1.066607
31.126613,1.016614
31.01662,1.02662
31.086631,1.096631
31.106644,1.116644
31.01665,1.02665
31.016653,1.026653
31.126655,1.016656
31.106656,1.116656
31.056664,1.066664
31.036666,1.046666
31.016677,1.026677
31.056679,1.066679
31.126688,1.016689
31.036699,1.046699
31.076704,1.086704
31.07671,1.08671
31.05673,1.06673
31.076731,1.086731
31.086742,1.096742
31.056754,1.066754
29.02676,1.03676
31.016761,1.026761
31.126763,1.016764
31.036768,1.046768
31.036774,1.046774
31.076803,1.086803
31.076806,1.086806
31.126814,1.016815
31.036822,1.046822
31.086823,1.096823
31.036831,1.046831
31.086838,1.096838
31.076839,1.086839
31.016851,1.026851
31.056853,1.066853
31.126859,1.01686
31.016863,1.026863
31.036873,1.046873
31.076878,1.086878
31.016884,1.026884
31.126892,1.016893
31.016893,1.026893
31.086895,1.096895
31.106899,1.116899
31.086904,1.096904
31.106914,1.116914
31.106917,1.116917
31.07692,1.08692
31.076929,1.086929
31.056937,1.066937
31.12694,1.016941
31.106953,1.116953
31.056979,1.066979
31.076983,1.086983
31.107001,1.117001
31.127003,1.017004
31.077007,1.087007
29.027008,1.037008
31.017022,1.027022
31.057039,1.067039
31.107058,1.117058
31.057063,1.067063
31.12709,1.017091
31.0771,1.0871
31.127102,1.017103
31.057108,1.067108
31.057111,1.067111
31.107118,1.117118
31.05712,1.06712
31.077124,1.087124
31.10713,1.11713
31.107139,1.117139
31.107151,1.117151
31.057153,1.067153
31.107169,1.117169
31.03717,1.04717
31.017175,1.027175
31.057183,1.067183
31.077187,1.087187
31.037209,1.047209
31.077217,1.087217
31.057222,1.067222
31.017223,1.027223
31.077223,1.087223
31.077241,1.087241
31.107247,1.117247
29.027248,1.037248
31.127249,1.01725
31.107253,1.117253
31.127258,1.017259
31.107268,1.117268
31.017274,1.027274
31.017289,1.027289
31.127291,1.017292
31.127297,1.017298
31.08733,1.09733
31.107343,1.117343
31.057354,1.067354
31.087363,1.097363
31.10737,1.11737
31.017373,1.027373
31.057384,1.067384
31.077391,1.087391
31.127405,1.017406
31.107421,1.117421
31.107436,1.117436
31.037449,1.047449
31.08745,1.09745
31.107454,1.117454
31.017457,1.027457
31.107466,1.117466
31.107475,1.117475
31.087483,1.097483
31.077496,1.087496
31.087519,1.097519
31.017523,1.027523
31.107529,1.117529
31.077538,1.087538
31.127552,1.017553
31.087555,1.097555
31.03756,1.04756
31.087561,1.097561
31.107562,1.117562
31.12757,1.017571
31.057585,1.067585
31.077601,1.087601
31.037608,1.047608
31.01761,1.02761
31.10761,1.11761
31.087612,1.097612
31.057624,1.067624
31.127633,1.017634
31.087663,1.097663
31.127663,1.017664
31.057672,1.067672
31.03768,1.04768
31.127684,1.017685
29.027692,1.037692
31.127699,1.0177
31.087717,1.097717
31.08772,1.09772
31.07773,1.08773
31.077733,1.087733
31.107742,1.117742
29.027744,1.037744
31.077766,1.087766
31.087768,1.097768
31.03777,1.04777
31.057789,1.067789
31.01779,1.02779
31.017799,1.027799
31.037803,1.047803
31.037806,1.047806
31.017826,1.027826
31.017832,1.027832
31.057837,1.067837
31.127858,1.017859
31.077859,1.087859
31.037884,1.047884
31.057888,1.067888
31.077892,1.087892
31.127897,1.017898
31.127936,1.017937
31.03795,1.04795
31.127957,1.017958
31.057966,1.067966
31.037968,1.047968
29.027968,1.037968
31.017979,1.027979
31.017982,1.027982
31.107988,1.117988
31.058008,1.068008
31.108012,1.118012
31.018024,1.028024
31.088029,1.098029
31.10803,1.11803
31.088038,1.098038
31.078039,1.088039
31.058041,1.068041
31.128041,1.018042
31.038049,1.048049
29.028052,1.038052
31.038055,1.048055
31.07806,1.08806
31.088065,1.098065
31.058086,1.068086
31.018105,1.028105
31.12811,1.018111
31.038127,1.048127
31.058131,1.068131
31.088149,1.098149
31.038154,1.048154
31.088164,1.098164
31.088191,1.098191
31.128194,1.018195
31.078195,1.088195
31.018198,1.028198
31.078204,1.088204
31.078207,1.088207
31.10821,1.11821
31.058212,1.068212
31.03822,1.04822
31.058233,1.068233
31.128233,1.018234
31.058257,1.068257
31.038262,1.048262
31.088272,1.098272
31.03828,1.04828
31.038283,1.048283
31.088287,1.098287
31.078288,1.088288
31.078294,1.088294
31.078297,1.088297
31.078309,1.088309
31.058317,1.068317
31.108321,1.118321
31.108324,1.118324
31.078327,1.088327
31.108327,1.118327
31.088344,1.098344
31.078375,1.088375
31.108384,1.118384
31.018408,1.028408
31.078435,1.088435
31.12844,1.018441
31.128446,1.018447
31.088455,1.098455
31.128455,1.018456
31.05847,1.06847
31.038478,1.048478
31.108483,1.118483
31.03849,1.04849
31.088494,1.098494
31.058497,1.068497
31.058503,1.068503
31.128503,1.018504
31.078507,1.088507
29.02852,1.03852
31.018528,1.028528
31.018534,1.028534
31.01854,1.02854
31.088545,1.098545
31.05856,1.06856
31.108573,1.118573
31.058578,1.068578
31.058581,1.068581
31.128587,1.018588
31.038589,1.048589
31.018594,1.028594
31.078594,1.088594
31.088599,1.098599
31.078606,1.088606
31.128611,1.018612
31.078621,1.088621
31.078642,1.088642
31.128653,1.018654
31.128656,1.018657
31.018657,1.028657
31.058659,1.068659
31.01866,1.02866
31.088665,1.098665
31.078675,1.088675
31.128686,1.018687
31.038694,1.048694
31.058743,1.068743
31.01875,1.02875
31.10875,1.11875
31.128755,1.018756
31.058758,1.068758
31.018765,1.028765
31.038769,1.048769
31.078783,1.088783
31.108789,1.118789
31.018807,1.028807
31.018813,1.028813
31.078819,1.088819
31.108819,1.118819
31.038862,1.048862
31.058866,1.068866
31.128875,1.018876
31.088881,1.098881
31.088884,1.098884
29.028892,1.038892
31.088905,1.098905
31.078906,1.088906
31.078909,1.088909
31.088932,1.098932
31.058935,1.068935
31.078936,1.088936
31.108948,1.118948
31.038967,1.048967
29.028968,1.038968
31.058977,1.068977
31.108978,1.118978
31.038985,1.048985
31.128989,1.01899
..31.039,1.049
31.129001,1.019002
31.019005,1.029005
31.039009,1.049009
31.019014,1.029014
31.129031,1.019032
31.019035,1.029035
31.019068,1.029068
31.089082,1.099082
31.109092,1.119092
31.089094,1.099094
31.019122,1.029122
31.109137,1.119137
31.059139,1.069139
31.089145,1.099145
31.109146,1.119146
31.019155,1.029155
31.079179,1.089179
31.079194,1.089194
31.039204,1.049204
31.019218,1.029218
31.129244,1.019245
31.039249,1.049249
31.079263,1.089263
31.019275,1.029275
31.10929,1.11929
31.089301,1.099301
31.129304,1.019305
31.08931,1.09931
31.089313,1.099313
31.129313,1.019314
31.109323,1.119323
31.079326,1.089326
31.059328,1.069328
31.03933,1.04933
31.019344,1.029344
31.05937,1.06937
31.059373,1.069373
31.109392,1.119392
31.109395,1.119395
31.089397,1.099397
31.059415,1.069415
31.019431,1.029431
31.109431,1.119431
31.039435,1.049435
31.039447,1.049447
31.089451,1.099451
31.109464,1.119464
31.079467,1.089467
31.079482,1.089482
31.08949,1.09949
31.039519,1.049519
29.029532,1.039532
31.079536,1.089536
31.089547,1.099547
31.129547,1.019548
31.109548,1.119548
31.059559,1.069559
31.109566,1.119566
31.019575,1.029575
31.059577,1.069577
31.089625,1.099625
31.059637,1.069637
31.089658,1.099658
31.019662,1.029662
31.129673,1.019674
31.039693,1.049693
31.059694,1.069694
29.029696,1.039696
31.0897,1.0997
31.019701,1.029701
31.019731,1.029731
31.03975,1.04975
31.08976,1.09976
31.039765,1.049765
31.129766,1.019767
31.01977,1.02977
31.019773,1.029773
31.03978,1.04978
31.019812,1.029812
31.129817,1.019818
31.01983,1.02983
31.059832,1.069832
31.079833,1.089833
31.089838,1.099838
31.089841,1.099841
31.039843,1.049843
31.12985,1.019851
31.019851,1.029851
31.039864,1.049864
31.059868,1.069868
31.079872,1.089872
31.039876,1.049876
31.109884,1.119884
31.059889,1.069889
31.059913,1.069913
31.089925,1.099925
31.079956,1.089956
31.079959,1.089959
31.019968,1.029968
31.129976,1.019977
31.059997,1.069997

I used a crappy little Perl script to reformat both data sets and run the comparision:

Code:


#!/usr/bin/perl -w

#use strict;
my $message = "Compare my PDP output to Joe's.";

my $dump_joes = 0;
my $joes_dump_file = "joes_in_my_format.txt";

my $outfile = "-";
my $joes = "-";
my $mine = "-";

my $script_executable = $0;
my $script_name       = "";
if ($script_executable =~ /[\.\/]*(\w+\.pl)/) {
  $script_name      = "$1";
}

# ---------------------------------------------------------------------
my $script  = <<SCRIPT;
$script_name  - $message
SCRIPT

my $usage = <<EOM;

$script
Usage:
   $script_name -j JOES_FILE -m MY_FILE [-dj] [-o outfile]

Parameters:
   -j Joe's List  Cut-and-paste of Joe's list from forum.
   -m My List     Recovered struture from HP50G memory card.
   -dj            Dump Joe's data in a format closer to mine.
   -o outfile     Output file. Uses STDOUT if not given.
   -h             This help script.

Examples:
  \$ $script_name -j joes.txt -m pdp.txt -dj
  - Read in Joe's data and my data. Parse the 2 and compare entires
    in both directions; mine in his and his in mine.

EOM


#######################################################################

get_options();

open OUT, "> $outfile" or die "ERROR: Cannot open file '$outfile' for writing: $!\n";

my %joes = %{read_joes($joes)};
my %mine = %{read_mine($mine)};

for my $date (sort keys %joes) {
  if (not exists $mine{$date}) {
    printf OUT "Date in Joe's but not mine: %0s\n", $date;
  }
}

for my $date (sort keys %mine) {
  if (not exists $joes{$date}) {
    printf OUT "Date in mine but not Joe's: %0s\n", $date;
  }
}

close OUT;


#######################################################################
#
sub read_mine {
  my $file = shift;
  my (%mine);
  local $_;
  open IN, $file or die "ERROR: Cannot open file '$file' for reading: $!\n";
  
  while (<IN>) {
    next if /^\s*$/ or /^\s*#/;
    chomp; chomp;
    if (/(\d+)\.(\d+)/) {
      my $day = $1;
      my $month_year = "$2";
      # Zero fill any 'short' years
      while (length $month_year < 6) {
        $month_year .= "0";
      }
      $date_format = sprintf "%02d.%0s", $day, $month_year;
      if (not exists $mine{$date_format}) {
        $mine{$date_format} = "$day, $month_year";  # Content does not matter, just key.
      } else {
        print OUT "# Duplicate found at %0d, %0s\n", $day, $month_year;
      }
    }
  }
  close IN;
  
  if ($dump_joes) {
    open JOES, "> $joes_dump_file" or die "ERROR: Cannot open file '$joes_dump_file' for writing: $!\n";
    for my $date (sort keys %joes) {
      printf JOES "%0s\n", $date;
    }
    close JOES;
  }
  
  return \%mine;
} # read_mine


#######################################################################
#
sub read_joes {
  my $file = shift;
  my (%joes);
  local $_;
  open IN, $file or die "ERROR: Cannot open file '$file' for reading: $!\n";
  
  my ($month_key);
  while (<IN>) {
    next if /^\s*$/;
    chomp; chomp;
    if (/(\w{3}\/\w{3})/) {
      $month_key = $1;
    } elsif (/\d+/) {
      my @years = split /\s+/, $_;
      
      # If this is the Dec/Jan region, we have duplicate/consecutive years.
      # Decimate this to only show the first year.
      if ($month_key eq "Dec/Jan") {
        my (@decimated_years);
        for (my $k = 0; $k < scalar @years; $k += 2) {
          push @decimated_years, $years[$k];
        }
        @years = @decimated_years;
      }
      
      foreach my $year (@years) {
        $date_format = build_date_from_joes($year, $month_key);
        if (not exists $joes{$date_format}) {
          $joes{$date_format} = "$year, $month_key";  # Content does not matter, just key.
        } else {
          print OUT "# Duplicate found at %0d, %0s\n", $year, $month_key;
        }
      }
    }
  }
  close IN;
  return \%joes;
} # read_joes


#######################################################################
#
#
#
sub build_date_from_joes {
  my $year = shift;
  my $month_key = shift;
  my ($date);
  local $_;
  my %months = (Jan   => 1,
                Feb   => 2,
                Mar   => 3,
                May   => 5,
                Jul   => 7,
                Aug   => 8,
                Oct   => 10,
                Dec   => 12);
  
  if ($month_key =~ /^Feb/) {
    $date = "29.02" . sprintf "%4d", $year;
  } elsif ($month_key =~ /^(\w{3})\//) {
    $date = "31." . sprintf "%02d%04d", $months{$1}, $year;
  } else {
    die "# ERROR: Invalid month key-code: $month_key\n";
  }
  
  return $date;
} # build_date_from_joes 



#######################################################################
#######################################################################
#
# Process the command line option list.
#
sub get_options {
  while (my $arg = shift(@ARGV)) {
    # See if help is asked for
    if (($arg eq '-h') or ($arg eq '--help')) {
      print "$usage\n";
      die "\n";
    }

    elsif ($arg eq '-j') {
      $joes = shift(@ARGV);
    }

    elsif ($arg eq '-m') {
      $mine = shift(@ARGV);
    }

    elsif ($arg eq '-dj') {
      $dump_joes = 1;
    }

    elsif ($arg eq '-o') {
      $outfile = shift(@ARGV);
    }
  }

  ###############################################
  # Check sanity of command line parameters, etc.
  unless ($joes and $mine) {
    die "ERROR: Not enough files. Use '-j joes.file -m my.file''\n";
  }
    
  return;
} # get_options

[David Hayden]

(09-27-2014 04:47 PM)Neil Hamilton Wrote:  I gave this a shot in RPL. First attempt yielded 70 s/yr on a 49G+, not too good. This scanned EVERY day of the year (some twice!). Fairly brain dead...

The criteria for the contest was for size only. Runtime didn't matter. My winning entry also scanned every date in the year plus 12/31 of the previous year and 1/1 of the next. It was slower than a turtle going uphill but that didn't matter. I'll post it when I have some time and the source code nearby.

Dave

[Neil Hamilton]

(09-28-2014 01:39 PM)David Hayden Wrote:  The criteria for the contest was for size only.

Actually it did have a few more constraints, "all programs must return the correct answers to qualify" among them.

I cannot hope to compete with the Gods of HP Calculators in terms of size or speed. I am nowhere near talented enough. :-)

My only goal was to run through ALL the years and see what I got. For that, 70 s/yr -- or even 23 s/yr -- was not going to cut it. That is the main reason I was looking to pick up the speed.

Having built a program that was suffiently quick (< 1 s/yr for a small range of years), and having obtained the definitive list, I was a bit surprised that my list was longer than the the definitive one. That is my biggest puzzle right now.

I am also wondering why the performance dropped to ~1.25 s/yr when run against a set with an ~8400 year span. The only thing I can think of is that since I push my answers to the stack and with 1000-odd entries on the stack, that might be slowing it down. My output was a string per PDP something like this "31.016401, 1.026401" -- not very compact. Any thoughts?

[David Hayden]

(09-29-2014 11:13 AM)Neil Hamilton Wrote:  I am also wondering why the performance dropped to ~1.25 s/yr when run against a set with an ~8400 year span. The only thing I can think of is that since I push my answers to the stack and with 1000-odd entries on the stack, that might be slowing it down.

The large date span probably means that the calculator would do garbage collection at least one, and the items on the large number of items on the stack would make it slow. On the other hand, putting the items in a list would probably be even worse. When you add to a list, it actually creates a new list and copies the old and new items into it. Adding the 877th item copies 866 items, and the new one. So that would probably be even slower. Try dropping the items into a pre-sized array.

[Joe Horn]

(09-28-2014 11:58 AM)Neil Hamilton Wrote:  Maybe I am misunderstanding something in the format but it appears that there may be up to 30 entries missing from your table. I get 1057 pairs in the 1583 - 9999 range and you get 1027. ... Am I missing something?

(09-29-2014 11:13 AM)Neil Hamilton Wrote:  Having built a program that was suffiently quick (< 1 s/yr for a small range of years), and having obtained the definitive list, I was a bit surprised that my list was longer than the the definitive one. That is my biggest puzzle right now.

Bill Butler solved this "puzzle" -- I must've accidentally missed a block when I copied & pasted from the UBASIC output. The additional PDP's you found are absolutely correct, and I'll edit them into the "complete list" (hah!) ASAP. Thankfully none of those years were used as test cases for judging the contest. Many thanks for catching the missing PDP's!

[Jeff O.]

(09-29-2014 12:43 PM)Joe Horn Wrote:  Thankfully none of those years were used as test cases for judging the contest.

What were the test cases used for judging?

[Thomas Klemm]

(09-28-2014 11:58 AM)Neil Hamilton Wrote:  

Code:

#use strict;

ಠ_ಠ

[Neil Hamilton]

(09-29-2014 04:57 PM)Thomas Klemm Wrote:  

(09-28-2014 11:58 AM)Neil Hamilton Wrote:  

Code:

#use strict;

ಠ_ಠ

Good eyes, Thomas! OK, I cheated a little bit! The Perl I have on my computer has the majorly annoying feature of sometimes displaying syntax errors as if they were occuring somewhere deep in the bowels of some standard packages rather than showing me where the issue really is -- in my code. I sometimes start to build a script with this turned off and switch it on later. Forgot this time...

Put 'my' in front of "$date_format" on lines 95 and 145 (as per my current version) and remove the comment on 'strict' and you are off to the races...

The "Joe" file is simply a cut-and-paste of his earlier list. The "Mine" file can be the list I published.

Command line could be:

Code:


$ perl whatever_you_called_this_script.pl  -j joes.txt -m pdp3.txt 
Date in mine but not Joe's: 31.016401
Date in mine but not Joe's: 31.016422
...

Joe, I suspected that it was simply a few lines were deleted from the output. A cut-and-paste issue makes perfect sense.

[Joe Horn]

(09-29-2014 01:41 PM)Jeff O. Wrote:  

(09-29-2014 12:43 PM)Joe Horn Wrote:  Thankfully none of those years were used as test cases for judging the contest.

What were the test cases used for judging?

Rats... I seem to have discarded the piece of note paper that the test dates (and expected results) were scribbled on. But I know that none of the missing years were used because I only used years that were in my incomplete table. If I ever find that piece of paper, I'll post the years.

EDIT: OOH OOH, I found it! (Doing so caused an avalanche in my room, but I digress). Here are the test years and their expected results:

1586: Oct 31, Nov 1
1588: Aug 31, Sep 1
2014: No PDP's
2020: Dec 31
2021: Jan 1
2080: Feb 29, Mar 1, May 31, Jun 1
2413: Aug 31, Sep 1, Dec 31
2414: Jan 1, Oct 31, Nov 1
3688: Feb 29, Mar 1, Dec 31
7968: Feb 29, Mar 1, Mar 31, Apr 1

[Jeff O.]

(09-30-2014 01:20 AM)Joe Horn Wrote:  EDIT: OOH OOH, I found it! (Doing so caused an avalanche in my room, but I digress).

Thanks for the information. (Sorry about the avalanche.)

I developed a couple of wp34s versions based on a couple of methods to attack the problem. Happily, they both produce the correct results for the test cases and all other years I have tried from the complete list. One version is 83 steps and reasonably fast. (If the year has no PPDs it finishes in about 1.5 seconds. If there are PPDs, they are displayed sequentially during pauses, so execution time is extended by the pause time for each date.) Second version is 50 steps, but it is much, much slower than the first version, taking about 20 seconds for years with no PPDs. Scanning through the above posts without reading in detail (to avoid hints or ideas), I see that Eric's version is 50 steps and Paul's is only 44. I doubt that my slooowww 50-stepper is comparable to those, so I think I have a ways to go. Guess I’ll keep messing around for a while (for the fun it - which is the point, right?) to see if I can come up with a better way.

[BruceH]

(09-24-2014 09:31 AM)Paul Dale Wrote:  I haven't checked all the myriad of Julian to Gregorian calendar changeovers over the years to see if any of these produced three odd days in a row or not and, if there are some, checked them for primality.

This is obviously possible and should be checked. However, I rather doubt the contest was meant to involve such nastinesses.

In 2011, Samoa skipped a day to jump from behind the International Date Line to be ahead of it (so as to be on the same date as their major trading partners). They did this by skipping December 30th, meaning they had three odd days in a row: 29th then 31st December 2011, followed by 1st January 2012. Fortunately for this competition, none of those dates are prime. :-)

[Werner]

My attempt.
Independent of the date settings, and will run on a 48G or newer.
Maybe the elegance and efficiency will make the judges gasp in awe. One can always hope ;-)

Code:

\<<
  \-> Y
  \<<
@ list of cases to test.
@ first object is the month number:
@ -last test case is month 1 of the next year, and if you construct yyyymm01 as (y*100 + m)*100 +1 then m=101 will do the trick
@ -the first case reverses the dates so that the correct date will be dropped in case of PDP
@  here, y*1e4 + m*100 + 1 = (y-1)*1e4 + 1231, and the m works out to be -87.7 ;-)
@ second is the difference between the first day of the month and the last of the previous month
@ third ob is the nr of objects to drop in case of a PDP (1 for the first and last case)
    { {-87.7 -8870 1} {2 70 0} }
    IF Y LEAP? THEN { { 3 72 0 } } + END
    { {4 70 0} {6 70 0} {8 70 0} {9 70 0} {11 70 0} {101 8870 1} } +
    1
    \<< 
      EVAL \-> m d n
      \<<
        @ construct yyyymm01
        Y 100 * m + 100 * 1 +
        IF DUP ISPRIME? THEN
          @   substract d to get the day before
          DUP d - SWAP
          OVER ISPRIME? n 2 IFTE DROPN
        ELSE DROP
        END
      \>>
    \>>
    DOLIST
  \>>
\>>


@ without the local environment..
\<<
  \-> Y
  \<<

    { {1 -8870 -87.7 } {0 70 2} }
    IF Y LEAP? THEN { { 0 72 3 } } + END
    { {0 70 4} {0 70 6} {0 70 8} {0 70 9} {0 70 11} {1 8870 101} } +
    1
    \<< EVAL
        @ construct yyyymm01
        Y 100 * + 100 * 1 +
        IF DUP ISPRIME? THEN
          @  get the day before
          DUP ROT - SWAP
          OVER ISPRIME? 4 ROLL 2 IFTE
        ELSE 3
        END
        DROPN
    \>>
    DOLIST
  \>>
\>>

ISPRIME?
@ Courtesy of John H. Meyers
\<<
  { DUP2 MOD NOT { DUP2 > { DROP2 -1 2 } IFT } IFT }
  \-> p
  \<< 1 MAX 2 p EVAL 1 + p EVAL 2 + p EVAL 2 +
      WHILE DUP2 SQ \>= REPEAT
          p EVAL 4 + p EVAL 2 + p EVAL 4 + p EVAL
      2 + p EVAL 4 + p EVAL 6 + p EVAL 2 + p EVAL 6 +
      END DROP 1 >
   \>>
\>>

LEAP?
@ Courtesy of Christian Meland
\<< 4 2 ALOG DUP2 * 3 ->LIST MOD EVAL XOR SAME \>>

Cheers, Werner

[C.Ret]

The version proposed by Werner inspires me and I produce the following codes on my poor HP-28S.

Code:

HHC2014:
« { -8769  131 228 331 430 531 630 731 831 930 1031 1130 1231 } 
  IF OVER LEAP? THEN 3 229 PUT END 
  SWAP 1E4 * → Lst y0
  « { } y0 1 +
    1 13 FOR i
       i 13 < 100 8900 IFTE +
       IF y0 Lst i GET + PRIME?
         THEN IF DUP PRIME? THEN SWAP OVER + SWAP END END
    NEXT DROP » »

The last DROP instruction is facultative; it's only clean up stack to only return the list of PDP.

As there is no native ISPRIME?, ISLEAP? or calendar functions on HP28S/C, I have to propose one homebrew version:

Code:

LEAP?:
« DUP    4 MOD 
  OVER 100 MOD NOT 
  ROT  400 MOD AND OR NOT »

This Leap Year tester is directly inspired from the version published by Werner/Christian Meland (but adapted to HP28S/C specific environment)

Code:

PRIME?:
« → p
  « 2 WHILE DUP SQ p ≤ 1 FC? AND
           REPEAT 
             IF p OVER MOD
             THEN NXTODD 
             ELSE 1 SF END END
    SIGN FC?C » »

Of course, the following propose PRIME? is not really fast. A better strategy has to be adopted here to reduce time need for testing as large integer as 20141231 or 99991231.
But this may be the subject of another MPO challenge that will spare batteries!

Code:

NXTODD:
«  DUP 2 MOD + 1 + »

Please note that NXTODD is store as an independent program to facilitate reading (and a potential evolution of the code). It may advantageously change into any NEXTPRIME function.

Also, flag 1 have to be clear before the first use of PRIME? (this spare a 1 CF at the beginning of the program) But have any importance only at first use, since the last instruction clear flag 1 whatever the result (cf. FC?C )

[Werner]

JHM's routine should work if you replace the IFTs by their IF THEN END counterparts:
(untested)

Code:

\<<
  \<< IF DUP2 MOD NOT THEN 
        IF DUP2 > THEN DROP2 -1 2 END 
        END
  \>>
  \-> p
  \<< 1 MAX 2 p EVAL 1 + p EVAL 2 + p EVAL 2 +
      WHILE DUP2 SQ \>= REPEAT
          p EVAL 4 + p EVAL 2 + p EVAL 4 + p EVAL
      2 + p EVAL 4 + p EVAL 6 + p EVAL 2 + p EVAL 6 +
      END DROP 1 >
   \>>
\>>

Remark that I changed the ultimate test to 1 >
This way it will work for 0 and 1, too. I edited my previous post as well.

Or else, my own simple concoction.

Code:

\<<
  1 MAX 2
  IF DUP2 MOD THEN 1 +
  IF DUP2 MOD THEN 2 +
  IF DUP2 MOD THEN 2 + 
  ELSE SWAP END
  ELSE SWAP END
  ELSE SWAP END
  WHILE DUP2 SQ \>= REPEAT
    IF DUP2 MOD THEN 4 +
    IF DUP2 MOD THEN 2 +
    IF DUP2 MOD THEN 4 +
    IF DUP2 MOD THEN 2 +
    IF DUP2 MOD THEN 4 +
    IF DUP2 MOD THEN 6 +
    IF DUP2 MOD THEN 2 +
    IF DUP2 MOD THEN 6 +
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
    ELSE SWAP END
  END
  \>=
\>>

Yet, to speed up the PDP routine, consider the following:
If yyyymm01 is prime and the day before isn't, then we have performed a lengthy primality testing for nothing.
What we should have is a routine BOTHPRIME? that tests two numbers for divisibility by ever increasing factors at the same time - If both are prime, that will gain us nothing, but if one or both are not, then we will gain a lot of time. I think.
How many times does it happen that yyyymm01 is prime and the day before isn't?
To be continued..

Werner

[Jeff O.]

Discussion about the 2014 contest seems to have waned a bit, but I'll go ahead and post an update on my progress. I was able to shorten my slow version to 44 steps. I had a slightly faster version at 50 steps. My reasonably fast version was stuck at 83 steps and I did not see any opportunities to improve that by much. I was not particularly satisfied with the shorter versions due to the speed, or the longer version based on length, so I kept on trying to come up with new approaches, thought of one, and developed it. (No earth-shaking insights I'm sure, just different than previous attempts.) I was able to develop a 44 step program that seems as fast as my 83 step version. There may be opportunities to shave a few steps off of that, but I think I'm pretty satisfied at this point. In case anyone is interested, here it is:

Code:

YYYY is input year
YYYx is year before input year
YYYz is year after input year
YYY? is indeterminate, could be YYYY, YYYx or YYYz, depending on the situation
calculator must be in yyyy.mmdd date mode

Operation - key in the year you wish to check for Prime Pair Dates, press XEQ 'PPD'.
Program will display any prime pair dates in that year in chronological order.  When
done, it will display the input year.  (Ignore any values in the Y display if you have 
Y display on.)

001    LBL 'PPD'     Label "Prime Pair Dates"
002    STO 03        Store input year in register 3 
003    SDL 004       multiply by 10000
004    INC X         add 1 to YYYY0000, now have YYYY0001
005    SDR 002       divide by 100 to get in form to allow month to be incremented
006    STO 01        store YYYY00.01 in reg 1
007    #11           enter constant 11
008    STO 04        store 11 in loop counter
009    XEQ 01        check YYYx.1231/YYYY0101, YYYY0131/0201…YYYY1031/1101*
010    DSE 04        decrement counter
011    BACK 002      go back to check next date pair
012    #89           when done checking through 1031/1101, enter constant 89
013    STO+ 01       add 89 to YYYY11.01 to get YYYz00.01
014    XEQ 01        check YYYY.1231/YYYz0101
015    RCL 03        recall input year to display when complete
016    STOP          
017    LBL 01        subroutine to check date pairs for prime
018    INC 01        increment month
019    RCL 01        recall first of month date
020    SDL 02        multiply by 100 to get in proper form
021    PRIME?        is first of month date prime?
022    SKIP 001      if prime, skip to check last of previous month
023    RTN           if not prime, return to get next month
024    SDR 004       divide by 10,000 to get in form to allow date arithmetic
025    1             enter 1
026    +/-           enter -1
027    DAYS+         subtract 1 day from 1st of month to get last of previous month
028    SDL 004       multiply by 10000 to get in proper form
029    PRIME?        is last of prior month date prime?
030    SKIP 001      if prime, skip to display prime date(s)
031    RTN           if not prime, return to get next month
032    RCL 01        recall first of month date
033    SDL 002       multiply by 100 to get in proper form for display
034    <>YYXX        re-order stack for display in chronological order
035    XEQ 02        execute display subroutine
036    <>TTTT        re-order stack to display second date
037    LBL 02        subroutine to display prime date(s)
038    SDR 004       divide year by 10000
039    IP            take integer portion to get year value YYY?
040    x=/=? 03      compare YYY? to input year
041    SKIP 002      if not equal, do not display prime date, it is in wrong year
042    <>YYTT        re-order stack to display date
043    PSE 25        pause to display prime date
044    RTN           

* - 1130 and 1201 can not be a prime pair, so stop after checking 1031/1101 prior
    to checking 1231.  This program does check other non-possible prime pairs, e.g.
    430/501, 630/701 up to that point.  This beats checking all days of the year :-)

For the heck of it, I converted Neil's listing of prime date pairs to a list of years with at least one PPD and all PPDs in each such year. There are 1121 years between 1583 and 9999 which have at least one Prime Pair Date (i.e. half of a prime date pair). 218 years have one PPD, 839 have two PPDs, 40 have three PPDs, 23 have four PPDs, none have five PPDs, and one year has the maximum of 6 PPDs, that year being 1679. That totals 2114 individual dates that are one-half of a prime pair, which agrees with Neil's total of 1057 prime pairs. The most common prime pair dates are 31-Jan and 01-Feb, occurring 153 times. The others occur with the following frequency:

31-Dec/01-Jan: 129 occurrences
31-Jan/01-Feb: 153 occurrences
29-Feb/01-Mar: 45 occurrences
31-Mar/01-Apr: 151 occurrences
31-May/01-Jun: 146 occurrences
31-Jul/01-Aug: 149 occurrences
31-Aug/01-Sep: 138 occurrences
31-Oct/01-Nov: 146 occurrences

1-Jan and 31-Dec never occur in the same year.

Here's the complete list:

Code:

1586    31-Oct, 01-Nov
1588    31-Aug, 01-Sep
1600    31-Dec
1601    01-Jan
1608    31-Mar, 01-Apr
1613    31-Jan, 01-Feb
1621    31-Dec
1622    01-Jan
1629    31-Mar, 01-Apr
1632    31-Mar, 01-Apr
1636    29-Feb, 01-Mar
1652    31-Oct, 01-Nov
1664    31-Jul, 01-Aug
1672    31-Aug, 01-Sep
1674    31-Mar, 01-Apr
1678    31-Aug, 01-Sep
1679    31-Jan, 01-Feb, 31-Jul, 01-Aug, 31-Oct, 01-Nov
1697    31-Jul, 01-Aug
1706    31-Jul, 01-Aug
1709    31-Oct, 01-Nov
1732    31-May, 01-Jun
1733    31-Oct, 01-Nov
1747    31-Dec
1748    01-Jan
1764    31-Mar, 01-Apr
1769    31-Jan, 01-Feb
1787    31-Jan, 01-Feb
1793    31-Jan, 01-Feb, 31-Oct, 01-Nov
1796    31-Jul, 01-Aug
1804    31-May, 01-Jun
1805    31-Oct, 01-Nov
1810    31-Dec
1811    01-Jan, 31-Oct, 01-Nov
1824    31-Mar, 01-Apr
1828    31-Dec
1829    01-Jan
1835    31-Jan, 01-Feb
1841    31-Jul, 01-Aug
1847    31-Jul, 01-Aug
1866    31-Mar, 01-Apr
1870    31-May, 01-Jun
1876    31-May, 01-Jun
1881    31-Mar, 01-Apr
1886    31-Jul, 01-Aug
1891    31-Dec
1892    01-Jan
1913    31-Jul, 01-Aug
1921    31-May, 01-Jun
1924    29-Feb, 01-Mar
1925    31-Jan, 01-Feb
1930    31-Dec
1931    01-Jan
1950    31-Mar, 01-Apr
1972    31-Dec
1973    01-Jan
1978    31-Dec
1979    01-Jan, 31-Jan, 01-Feb
1983    31-Mar, 01-Apr
1987    31-Dec
1988    01-Jan
1990    31-Aug, 01-Sep
1997    31-Oct, 01-Nov
2002    31-May, 01-Jun
2017    31-Aug, 01-Sep
2018    31-Jul, 01-Aug
2020    31-Dec
2021    01-Jan
2028    29-Feb, 01-Mar
2029    31-Dec
2030    01-Jan
2036    31-Oct, 01-Nov
2064    31-Mar, 01-Apr
2068    31-Aug, 01-Sep
2075    31-Jan, 01-Feb
2080    29-Feb, 01-Mar, 31-May, 01-Jun
2081    31-Oct, 01-Nov
2093    31-Jul, 01-Aug
2107    31-Aug, 01-Sep
2110    31-May, 01-Jun
2122    31-May, 01-Jun
2132    31-Oct, 01-Nov
2136    31-Mar, 01-Apr
2138    31-Jan, 01-Feb
2150    31-Oct, 01-Nov
2161    31-Dec
2162    01-Jan
2165    31-Jan, 01-Feb
2171    31-Jan, 01-Feb
2204    31-Jul, 01-Aug
2211    31-Mar, 01-Apr
2216    31-Oct, 01-Nov
2242    31-Aug, 01-Sep
2257    31-May, 01-Jun
2262    31-Mar, 01-Apr
2264    31-Jan, 01-Feb
2281    31-Aug, 01-Sep
2282    31-Jul, 01-Aug
2289    31-Mar, 01-Apr
2290    31-Aug, 01-Sep
2291    31-Jan, 01-Feb
2302    31-Aug, 01-Sep
2304    29-Feb, 01-Mar
2308    29-Feb, 01-Mar
2312    31-Oct, 01-Nov
2315    31-Jul, 01-Aug
2320    31-Aug, 01-Sep
2330    31-Jan, 01-Feb
2338    31-May, 01-Jun
2372    31-Jan, 01-Feb
2374    31-Aug, 01-Sep
2383    31-Dec
2384    01-Jan
2385    31-Mar, 01-Apr
2396    31-Jul, 01-Aug
2404    31-Aug, 01-Sep
2413    31-Aug, 01-Sep, 31-Dec
2414    01-Jan, 31-Oct, 01-Nov
2420    31-Jan, 01-Feb, 31-Oct, 01-Nov
2425    31-May, 01-Jun
2435    31-Jul, 01-Aug, 31-Oct, 01-Nov
2437    31-Dec
2438    01-Jan, 31-Jan, 01-Feb
2444    31-Oct, 01-Nov
2446    31-Aug, 01-Sep
2448    29-Feb, 01-Mar
2456    31-Jan, 01-Feb
2485    31-May, 01-Jun
2508    29-Feb, 01-Mar
2510    31-Oct, 01-Nov
2511    31-Mar, 01-Apr
2531    31-Oct, 01-Nov
2533    31-Dec
2534    01-Jan
2535    31-Mar, 01-Apr
2539    31-May, 01-Jun, 31-Aug, 01-Sep
2540    31-Jul, 01-Aug
2542    31-May, 01-Jun
2561    31-Jul, 01-Aug
2570    31-Oct, 01-Nov
2574    31-Mar, 01-Apr
2576    31-Jan, 01-Feb
2581    31-Dec
2582    01-Jan
2600    31-Jan, 01-Feb
2602    31-Dec
2603    01-Jan
2611    31-Aug, 01-Sep
2614    31-Aug, 01-Sep
2615    31-Jul, 01-Aug
2617    31-Aug, 01-Sep
2633    31-Jan, 01-Feb
2634    31-Mar, 01-Apr
2650    31-Dec
2651    01-Jan
2660    31-Oct, 01-Nov
2674    31-May, 01-Jun
2680    31-May, 01-Jun
2689    31-Dec
2690    01-Jan
2706    31-Mar, 01-Apr
2713    31-May, 01-Jun
2728    31-Aug, 01-Sep
2729    31-Oct, 01-Nov
2731    31-May, 01-Jun
2737    31-May, 01-Jun
2765    31-Jan, 01-Feb
2776    31-Dec
2777    01-Jan, 31-Jul, 01-Aug
2781    31-Mar, 01-Apr
2798    31-Jul, 01-Aug
2801    31-Oct, 01-Nov
2802    31-Mar, 01-Apr
2814    31-Mar, 01-Apr
2818    31-May, 01-Jun
2829    31-Mar, 01-Apr
2834    31-Oct, 01-Nov
2847    31-Mar, 01-Apr
2850    31-Mar, 01-Apr
2864    31-Oct, 01-Nov
2867    31-Oct, 01-Nov
2876    31-Jan, 01-Feb
2884    31-May, 01-Jun
2885    31-Jan, 01-Feb
2900    31-Jan, 01-Feb
2912    31-Jul, 01-Aug, 31-Oct, 01-Nov
2926    31-Aug, 01-Sep
2927    31-Oct, 01-Nov
2932    31-Dec
2933    01-Jan, 31-Jan, 01-Feb
2940    31-Mar, 01-Apr
2944    31-May, 01-Jun
2945    31-Oct, 01-Nov
2951    31-Jul, 01-Aug
2987    31-Jan, 01-Feb
2990    31-Oct, 01-Nov
3000    31-Mar, 01-Apr
3014    31-Jul, 01-Aug
3036    29-Feb, 01-Mar
3039    31-Mar, 01-Apr
3047    31-Jan, 01-Feb
3068    31-Jan, 01-Feb
3072    31-Mar, 01-Apr
3079    31-Aug, 01-Sep
3083    31-Jan, 01-Feb
3085    31-May, 01-Jun
3097    31-Dec
3098    01-Jan
3107    31-Oct, 01-Nov
3109    31-Aug, 01-Sep
3114    31-Mar, 01-Apr
3122    31-Jul, 01-Aug
3124    29-Feb, 01-Mar
3131    31-Jul, 01-Aug
3155    31-Jan, 01-Feb, 31-Jul, 01-Aug
3171    31-Mar, 01-Apr
3173    31-Oct, 01-Nov
3176    31-Jul, 01-Aug
3186    31-Mar, 01-Apr
3190    31-Aug, 01-Sep
3210    31-Mar, 01-Apr
3212    31-Jul, 01-Aug
3221    31-Jan, 01-Feb
3223    31-Aug, 01-Sep
3226    31-May, 01-Jun
3252    31-Mar, 01-Apr
3260    31-Jul, 01-Aug
3264    29-Feb, 01-Mar
3266    31-Jul, 01-Aug
3267    31-Mar, 01-Apr
3274    31-May, 01-Jun, 31-Aug, 01-Sep
3278    31-Jul, 01-Aug
3285    31-Mar, 01-Apr
3289    31-May, 01-Jun
3297    31-Mar, 01-Apr
3298    31-Dec
3299    01-Jan
3317    31-Jan, 01-Feb
3327    31-Mar, 01-Apr
3328    31-Aug, 01-Sep
3344    31-Jul, 01-Aug
3346    31-Aug, 01-Sep
3351    31-Mar, 01-Apr
3377    31-Jul, 01-Aug
3379    31-Dec
3380    01-Jan
3388    31-May, 01-Jun
3395    31-Oct, 01-Nov
3398    31-Jul, 01-Aug
3407    31-Oct, 01-Nov
3424    29-Feb, 01-Mar
3428    31-Oct, 01-Nov
3430    31-Aug, 01-Sep
3439    31-Aug, 01-Sep
3441    31-Mar, 01-Apr
3470    31-Oct, 01-Nov
3472    31-May, 01-Jun
3475    31-Aug, 01-Sep
3480    31-Mar, 01-Apr
3487    31-Dec
3488    01-Jan
3508    31-Aug, 01-Sep
3511    31-May, 01-Jun
3515    31-Jan, 01-Feb
3521    31-Jul, 01-Aug
3538    31-Dec
3539    01-Jan
3546    31-Mar, 01-Apr
3554    31-Jul, 01-Aug
3564    31-Mar, 01-Apr
3572    31-Jul, 01-Aug
3574    31-Dec
3575    01-Jan, 31-Oct, 01-Nov
3591    31-Mar, 01-Apr
3598    31-May, 01-Jun
3611    31-Jul, 01-Aug
3614    31-Jan, 01-Feb
3632    31-Oct, 01-Nov
3633    31-Mar, 01-Apr
3634    31-Dec
3635    01-Jan
3640    31-Aug, 01-Sep
3648    31-Mar, 01-Apr
3653    31-Jul, 01-Aug
3661    31-Aug, 01-Sep
3670    31-Aug, 01-Sep
3685    31-Dec
3686    01-Jan
3688    29-Feb, 01-Mar, 31-Dec
3689    01-Jan
3692    31-Jul, 01-Aug
3694    31-Dec
3695    01-Jan
3710    31-Jul, 01-Aug
3727    31-Dec
3728    01-Jan
3747    31-Mar, 01-Apr
3748    29-Feb, 01-Mar
3755    31-Jul, 01-Aug
3758    31-Jul, 01-Aug
3787    31-May, 01-Jun
3800    31-Jul, 01-Aug, 31-Oct, 01-Nov
3816    29-Feb, 01-Mar
3818    31-Jul, 01-Aug
3820    29-Feb, 01-Mar
3822    31-Mar, 01-Apr
3827    31-Jan, 01-Feb
3853    31-Aug, 01-Sep
3855    31-Mar, 01-Apr
3857    31-Oct, 01-Nov
3862    31-May, 01-Jun
3868    31-May, 01-Jun
3875    31-Jul, 01-Aug
3877    31-May, 01-Jun
3886    31-Aug, 01-Sep
3887    31-Jul, 01-Aug
3894    31-Mar, 01-Apr
3896    31-Oct, 01-Nov
3899    31-Oct, 01-Nov
3901    31-Aug, 01-Sep
3904    29-Feb, 01-Mar
3914    31-Jan, 01-Feb
3920    31-Jul, 01-Aug
3923    31-Jan, 01-Feb
3928    31-May, 01-Jun
3929    31-Jan, 01-Feb
3932    31-Oct, 01-Nov
3944    31-Jan, 01-Feb
3995    31-Oct, 01-Nov
4000    31-Dec
4001    01-Jan
4007    31-Jul, 01-Aug
4016    31-Oct, 01-Nov
4024    31-Aug, 01-Sep
4064    31-Jul, 01-Aug
4073    31-Jul, 01-Aug
4084    31-May, 01-Jun
4088    31-Oct, 01-Nov
4099    31-Dec
4100    01-Jan
4118    31-Jul, 01-Aug
4123    31-May, 01-Jun
4135    31-Aug, 01-Sep
4141    31-Dec
4142    01-Jan
4150    31-May, 01-Jun
4157    31-Jul, 01-Aug
4162    31-Dec
4163    01-Jan
4171    31-Aug, 01-Sep
4181    31-Jul, 01-Aug, 31-Oct, 01-Nov
4189    31-Dec
4190    01-Jan
4202    31-Jan, 01-Feb
4210    31-Aug, 01-Sep
4220    31-Jan, 01-Feb
4225    31-May, 01-Jun
4231    31-May, 01-Jun, 31-Aug, 01-Sep
4240    31-Dec
4241    01-Jan
4246    31-Dec
4247    01-Jan
4252    31-Dec
4253    01-Jan, 31-Jul, 01-Aug
4262    31-Oct, 01-Nov
4271    31-Jan, 01-Feb
4298    31-Jul, 01-Aug
4306    31-Dec
4307    01-Jan
4310    31-Jul, 01-Aug
4323    31-Mar, 01-Apr
4328    31-Jan, 01-Feb
4334    31-Oct, 01-Nov
4340    31-Oct, 01-Nov
4349    31-Jul, 01-Aug
4352    31-Jan, 01-Feb
4364    31-Jul, 01-Aug
4365    31-Mar, 01-Apr
4383    31-Mar, 01-Apr
4388    31-Jul, 01-Aug
4394    31-Oct, 01-Nov
4396    31-May, 01-Jun
4400    31-Oct, 01-Nov
4409    31-Jan, 01-Feb
4411    31-May, 01-Jun, 31-Dec
4412    01-Jan
4415    31-Jan, 01-Feb
4417    31-May, 01-Jun
4445    31-Oct, 01-Nov
4449    31-Mar, 01-Apr
4456    31-May, 01-Jun
4459    31-Aug, 01-Sep
4464    29-Feb, 01-Mar
4467    31-Mar, 01-Apr
4478    31-Oct, 01-Nov
4480    31-May, 01-Jun
4484    31-Oct, 01-Nov
4486    31-Aug, 01-Sep
4490    31-Jan, 01-Feb
4491    31-Mar, 01-Apr
4525    31-Aug, 01-Sep
4528    31-May, 01-Jun, 31-Aug, 01-Sep
4538    31-Jan, 01-Feb
4559    31-Oct, 01-Nov
4567    31-Aug, 01-Sep
4571    31-Oct, 01-Nov
4580    31-Oct, 01-Nov
4585    31-May, 01-Jun
4597    31-Dec
4598    01-Jan, 31-Oct, 01-Nov
4629    31-Mar, 01-Apr
4630    31-Aug, 01-Sep
4642    31-Dec
4643    01-Jan, 31-Jul, 01-Aug
4650    31-Mar, 01-Apr
4663    31-May, 01-Jun
4669    31-May, 01-Jun
4684    31-Dec
4685    01-Jan, 31-Jul, 01-Aug
4693    31-May, 01-Jun
4695    31-Mar, 01-Apr
4701    31-Mar, 01-Apr
4722    31-Mar, 01-Apr
4726    31-May, 01-Jun
4732    31-Aug, 01-Sep
4752    31-Mar, 01-Apr
4756    31-Dec
4757    01-Jan
4765    31-Aug, 01-Sep
4769    31-Oct, 01-Nov
4779    31-Mar, 01-Apr
4781    31-Jan, 01-Feb
4790    31-Jan, 01-Feb
4793    31-Oct, 01-Nov
4796    31-Oct, 01-Nov
4802    31-Oct, 01-Nov
4803    31-Mar, 01-Apr
4807    31-May, 01-Jun
4813    31-Dec
4814    01-Jan
4816    31-May, 01-Jun
4834    31-May, 01-Jun
4836    31-Mar, 01-Apr
4871    31-Jan, 01-Feb, 31-Jul, 01-Aug
4873    31-May, 01-Jun
4874    31-Oct, 01-Nov
4876    31-May, 01-Jun
4881    31-Mar, 01-Apr
4912    31-Aug, 01-Sep
4914    31-Mar, 01-Apr
4915    31-Aug, 01-Sep
4925    31-Oct, 01-Nov
4927    31-Aug, 01-Sep
4934    31-Oct, 01-Nov
4935    31-Mar, 01-Apr
4936    29-Feb, 01-Mar
4948    31-May, 01-Jun
4950    31-Mar, 01-Apr
4979    31-Jan, 01-Feb
4990    31-Dec
4991    01-Jan
4992    31-Mar, 01-Apr
4996    31-Aug, 01-Sep, 31-Dec
4997    01-Jan
4999    31-May, 01-Jun
5000    31-Jan, 01-Feb
5003    31-Oct, 01-Nov
5004    29-Feb, 01-Mar
5015    31-Jan, 01-Feb
5020    29-Feb, 01-Mar
5029    31-Dec
5030    01-Jan
5039    31-Jul, 01-Aug, 31-Oct, 01-Nov
5041    31-May, 01-Jun
5045    31-Oct, 01-Nov
5053    31-Dec
5054    01-Jan
5067    31-Mar, 01-Apr
5068    31-Aug, 01-Sep
5080    31-Aug, 01-Sep
5082    31-Mar, 01-Apr
5093    31-Jul, 01-Aug
5096    31-Jan, 01-Feb
5104    31-Dec
5105    01-Jan
5108    31-Jan, 01-Feb
5110    31-May, 01-Jun
5116    29-Feb, 01-Mar
5129    31-Jan, 01-Feb
5132    31-Jan, 01-Feb
5144    31-Jul, 01-Aug
5150    31-Oct, 01-Nov
5153    31-Jan, 01-Feb
5158    31-Aug, 01-Sep
5161    31-Aug, 01-Sep
5196    29-Feb, 01-Mar
5229    31-Mar, 01-Apr
5239    31-Aug, 01-Sep
5244    29-Feb, 01-Mar
5255    31-Jul, 01-Aug
5272    31-Aug, 01-Sep
5273    31-Jan, 01-Feb
5276    31-Jul, 01-Aug
5294    31-Jul, 01-Aug
5298    31-Mar, 01-Apr
5302    31-May, 01-Jun
5306    31-Jan, 01-Feb
5326    31-Dec
5327    01-Jan, 31-Jan, 01-Feb
5338    31-May, 01-Jun
5359    31-May, 01-Jun
5371    31-Aug, 01-Sep
5374    31-Dec
5375    01-Jan, 31-Jan, 01-Feb
5378    31-Jan, 01-Feb
5389    31-May, 01-Jun
5396    31-Oct, 01-Nov
5399    31-Jul, 01-Aug
5425    31-May, 01-Jun
5428    31-Dec
5429    01-Jan, 31-Oct, 01-Nov
5437    31-Dec
5438    01-Jan
5441    31-Jan, 01-Feb
5455    31-Aug, 01-Sep
5461    31-May, 01-Jun
5469    31-Mar, 01-Apr
5473    31-Aug, 01-Sep
5480    31-Jan, 01-Feb
5483    31-Jul, 01-Aug
5486    31-Oct, 01-Nov
5512    31-May, 01-Jun
5524    31-Aug, 01-Sep
5531    31-Jan, 01-Feb
5537    31-Oct, 01-Nov
5541    31-Mar, 01-Apr
5542    31-Dec
5543    01-Jan
5557    31-Dec
5558    01-Jan
5560    29-Feb, 01-Mar
5570    31-Jan, 01-Feb
5580    31-Mar, 01-Apr
5582    31-Jan, 01-Feb
5584    31-Aug, 01-Sep
5588    31-Oct, 01-Nov
5603    31-Jul, 01-Aug
5613    31-Mar, 01-Apr
5614    31-Aug, 01-Sep
5616    29-Feb, 01-Mar
5618    31-Oct, 01-Nov
5619    31-Mar, 01-Apr
5635    31-May, 01-Jun
5642    31-Jul, 01-Aug
5643    31-Mar, 01-Apr
5647    31-Dec
5648    01-Jan
5650    31-Aug, 01-Sep
5652    29-Feb, 01-Mar
5655    31-Mar, 01-Apr
5658    31-Mar, 01-Apr
5659    31-Dec
5660    01-Jan
5680    29-Feb, 01-Mar
5681    31-Oct, 01-Nov
5693    31-Jan, 01-Feb
5709    31-Mar, 01-Apr
5716    31-Dec
5717    01-Jan
5721    31-Mar, 01-Apr
5726    31-Oct, 01-Nov
5735    31-Jul, 01-Aug
5738    31-Jan, 01-Feb
5745    31-Mar, 01-Apr
5764    31-Aug, 01-Sep
5768    31-Oct, 01-Nov
5776    31-May, 01-Jun
5785    31-May, 01-Jun
5788    31-Dec
5789    01-Jan
5804    31-Oct, 01-Nov
5818    31-Dec
5819    01-Jan
5823    31-Mar, 01-Apr
5839    31-Aug, 01-Sep
5840    31-Jan, 01-Feb
5848    31-Dec
5849    01-Jan
5850    31-Mar, 01-Apr
5887    31-Aug, 01-Sep
5897    31-Jul, 01-Aug
5909    31-Jan, 01-Feb
5915    31-Jul, 01-Aug
5919    31-Mar, 01-Apr
5930    31-Oct, 01-Nov
5953    31-Dec
5954    01-Jan
5955    31-Mar, 01-Apr
5956    31-May, 01-Jun
5968    31-May, 01-Jun
5976    31-Mar, 01-Apr
5990    31-Jan, 01-Feb
5992    31-Aug, 01-Sep
5996    31-Jul, 01-Aug
5998    31-Aug, 01-Sep
6042    31-Mar, 01-Apr
6050    31-Jan, 01-Feb
6058    31-Aug, 01-Sep
6064    31-Aug, 01-Sep
6073    31-May, 01-Jun
6082    31-May, 01-Jun
6089    31-Oct, 01-Nov
6092    31-Jul, 01-Aug
6099    31-Mar, 01-Apr
6103    31-May, 01-Jun, 31-Dec
6104    01-Jan
6112    31-May, 01-Jun
6113    31-Jul, 01-Aug
6118    31-May, 01-Jun
6124    29-Feb, 01-Mar
6125    31-Jul, 01-Aug
6153    31-Mar, 01-Apr
6158    31-Jul, 01-Aug
6167    31-Jul, 01-Aug, 31-Oct, 01-Nov
6181    31-May, 01-Jun
6184    31-Dec
6185    01-Jan
6196    31-May, 01-Jun, 31-Dec
6197    01-Jan, 31-Jan, 01-Feb
6200    31-Jan, 01-Feb
6201    31-Mar, 01-Apr
6203    31-Jan, 01-Feb
6208    31-Aug, 01-Sep, 31-Dec
6209    01-Jan
6226    31-Aug, 01-Sep
6235    31-Aug, 01-Sep, 31-Dec
6236    01-Jan
6242    31-Oct, 01-Nov
6251    31-Jul, 01-Aug
6255    31-Mar, 01-Apr
6257    31-Jul, 01-Aug
6259    31-Dec
6260    01-Jan
6270    31-Mar, 01-Apr
6273    31-Mar, 01-Apr
6275    31-Jul, 01-Aug
6280    31-Aug, 01-Sep
6281    31-Oct, 01-Nov
6283    31-May, 01-Jun
6298    31-Dec
6299    01-Jan, 31-Jan, 01-Feb
6301    31-May, 01-Jun
6314    31-Jan, 01-Feb
6317    31-Jan, 01-Feb
6320    31-Jan, 01-Feb
6326    31-Oct, 01-Nov
6328    31-May, 01-Jun
6343    31-Aug, 01-Sep
6353    31-Oct, 01-Nov
6394    31-Aug, 01-Sep
6396    29-Feb, 01-Mar
6397    31-May, 01-Jun
6401    31-Jan, 01-Feb
6408    29-Feb, 01-Mar
6422    31-Jan, 01-Feb
6424    31-Aug, 01-Sep
6428    31-Jan, 01-Feb
6435    31-Mar, 01-Apr
6436    29-Feb, 01-Mar
6446    31-Oct, 01-Nov
6452    31-Oct, 01-Nov
6458    31-Jul, 01-Aug
6460    29-Feb, 01-Mar
6475    31-May, 01-Jun
6479    31-Jul, 01-Aug
6488    31-Jan, 01-Feb
6526    31-Aug, 01-Sep
6527    31-Jan, 01-Feb
6530    31-Oct, 01-Nov
6532    31-May, 01-Jun, 31-Dec
6533    01-Jan
6539    31-Jan, 01-Feb
6541    31-May, 01-Jun
6544    31-Dec
6545    01-Jan, 31-Jan, 01-Feb
6547    31-Aug, 01-Sep
6548    31-Jan, 01-Feb
6549    31-Mar, 01-Apr
6554    31-Jan, 01-Feb
6560    31-Jan, 01-Feb
6581    31-Jan, 01-Feb
6599    31-Jul, 01-Aug
6607    31-May, 01-Jun
6613    31-Dec
6614    01-Jan
6620    31-Jan, 01-Feb
6631    31-Aug, 01-Sep
6644    31-Oct, 01-Nov
6650    31-Jan, 01-Feb
6653    31-Jan, 01-Feb
6655    31-Dec
6656    01-Jan, 31-Oct, 01-Nov
6664    31-May, 01-Jun
6666    31-Mar, 01-Apr
6677    31-Jan, 01-Feb
6679    31-May, 01-Jun
6688    31-Dec
6689    01-Jan
6699    31-Mar, 01-Apr
6704    31-Jul, 01-Aug
6710    31-Jul, 01-Aug
6730    31-May, 01-Jun
6731    31-Jul, 01-Aug
6742    31-Aug, 01-Sep
6754    31-May, 01-Jun
6760    29-Feb, 01-Mar
6761    31-Jan, 01-Feb
6763    31-Dec
6764    01-Jan
6768    31-Mar, 01-Apr
6774    31-Mar, 01-Apr
6803    31-Jul, 01-Aug
6806    31-Jul, 01-Aug
6814    31-Dec
6815    01-Jan
6822    31-Mar, 01-Apr
6823    31-Aug, 01-Sep
6831    31-Mar, 01-Apr
6838    31-Aug, 01-Sep
6839    31-Jul, 01-Aug
6851    31-Jan, 01-Feb
6853    31-May, 01-Jun
6859    31-Dec
6860    01-Jan
6863    31-Jan, 01-Feb
6873    31-Mar, 01-Apr
6878    31-Jul, 01-Aug
6884    31-Jan, 01-Feb
6892    31-Dec
6893    01-Jan, 31-Jan, 01-Feb
6895    31-Aug, 01-Sep
6899    31-Oct, 01-Nov
6904    31-Aug, 01-Sep
6914    31-Oct, 01-Nov
6917    31-Oct, 01-Nov
6920    31-Jul, 01-Aug
6929    31-Jul, 01-Aug
6937    31-May, 01-Jun
6940    31-Dec
6941    01-Jan
6953    31-Oct, 01-Nov
6979    31-May, 01-Jun
6983    31-Jul, 01-Aug
7001    31-Oct, 01-Nov
7003    31-Dec
7004    01-Jan
7007    31-Jul, 01-Aug
7008    29-Feb, 01-Mar
7022    31-Jan, 01-Feb
7039    31-May, 01-Jun
7058    31-Oct, 01-Nov
7063    31-May, 01-Jun
7090    31-Dec
7091    01-Jan
7100    31-Jul, 01-Aug
7102    31-Dec
7103    01-Jan
7108    31-May, 01-Jun
7111    31-May, 01-Jun
7118    31-Oct, 01-Nov
7120    31-May, 01-Jun
7124    31-Jul, 01-Aug
7130    31-Oct, 01-Nov
7139    31-Oct, 01-Nov
7151    31-Oct, 01-Nov
7153    31-May, 01-Jun
7169    31-Oct, 01-Nov
7170    31-Mar, 01-Apr
7175    31-Jan, 01-Feb
7183    31-May, 01-Jun
7187    31-Jul, 01-Aug
7209    31-Mar, 01-Apr
7217    31-Jul, 01-Aug
7222    31-May, 01-Jun
7223    31-Jan, 01-Feb, 31-Jul, 01-Aug
7241    31-Jul, 01-Aug
7247    31-Oct, 01-Nov
7248    29-Feb, 01-Mar
7249    31-Dec
7250    01-Jan
7253    31-Oct, 01-Nov
7258    31-Dec
7259    01-Jan
7268    31-Oct, 01-Nov
7274    31-Jan, 01-Feb
7289    31-Jan, 01-Feb
7291    31-Dec
7292    01-Jan
7297    31-Dec
7298    01-Jan
7330    31-Aug, 01-Sep
7343    31-Oct, 01-Nov
7354    31-May, 01-Jun
7363    31-Aug, 01-Sep
7370    31-Oct, 01-Nov
7373    31-Jan, 01-Feb
7384    31-May, 01-Jun
7391    31-Jul, 01-Aug
7405    31-Dec
7406    01-Jan
7421    31-Oct, 01-Nov
7436    31-Oct, 01-Nov
7449    31-Mar, 01-Apr
7450    31-Aug, 01-Sep
7454    31-Oct, 01-Nov
7457    31-Jan, 01-Feb
7466    31-Oct, 01-Nov
7475    31-Oct, 01-Nov
7483    31-Aug, 01-Sep
7496    31-Jul, 01-Aug
7519    31-Aug, 01-Sep
7523    31-Jan, 01-Feb
7529    31-Oct, 01-Nov
7538    31-Jul, 01-Aug
7552    31-Dec
7553    01-Jan
7555    31-Aug, 01-Sep
7560    31-Mar, 01-Apr
7561    31-Aug, 01-Sep
7562    31-Oct, 01-Nov
7570    31-Dec
7571    01-Jan
7585    31-May, 01-Jun
7601    31-Jul, 01-Aug
7608    31-Mar, 01-Apr
7610    31-Jan, 01-Feb, 31-Oct, 01-Nov
7612    31-Aug, 01-Sep
7624    31-May, 01-Jun
7633    31-Dec
7634    01-Jan
7663    31-Aug, 01-Sep, 31-Dec
7664    01-Jan
7672    31-May, 01-Jun
7680    31-Mar, 01-Apr
7684    31-Dec
7685    01-Jan
7692    29-Feb, 01-Mar
7699    31-Dec
7700    01-Jan
7717    31-Aug, 01-Sep
7720    31-Aug, 01-Sep
7730    31-Jul, 01-Aug
7733    31-Jul, 01-Aug
7742    31-Oct, 01-Nov
7744    29-Feb, 01-Mar
7766    31-Jul, 01-Aug
7768    31-Aug, 01-Sep
7770    31-Mar, 01-Apr
7789    31-May, 01-Jun
7790    31-Jan, 01-Feb
7799    31-Jan, 01-Feb
7803    31-Mar, 01-Apr
7806    31-Mar, 01-Apr
7826    31-Jan, 01-Feb
7832    31-Jan, 01-Feb
7837    31-May, 01-Jun
7858    31-Dec
7859    01-Jan, 31-Jul, 01-Aug
7884    31-Mar, 01-Apr
7888    31-May, 01-Jun
7892    31-Jul, 01-Aug
7897    31-Dec
7898    01-Jan
7936    31-Dec
7937    01-Jan
7950    31-Mar, 01-Apr
7957    31-Dec
7958    01-Jan
7966    31-May, 01-Jun
7968    29-Feb, 01-Mar, 31-Mar, 01-Apr
7979    31-Jan, 01-Feb
7982    31-Jan, 01-Feb
7988    31-Oct, 01-Nov
8008    31-May, 01-Jun
8012    31-Oct, 01-Nov
8024    31-Jan, 01-Feb
8029    31-Aug, 01-Sep
8030    31-Oct, 01-Nov
8038    31-Aug, 01-Sep
8039    31-Jul, 01-Aug
8041    31-May, 01-Jun, 31-Dec
8042    01-Jan
8049    31-Mar, 01-Apr
8052    29-Feb, 01-Mar
8055    31-Mar, 01-Apr
8060    31-Jul, 01-Aug
8065    31-Aug, 01-Sep
8086    31-May, 01-Jun
8105    31-Jan, 01-Feb
8110    31-Dec
8111    01-Jan
8127    31-Mar, 01-Apr
8131    31-May, 01-Jun
8149    31-Aug, 01-Sep
8154    31-Mar, 01-Apr
8164    31-Aug, 01-Sep
8191    31-Aug, 01-Sep
8194    31-Dec
8195    01-Jan, 31-Jul, 01-Aug
8198    31-Jan, 01-Feb
8204    31-Jul, 01-Aug
8207    31-Jul, 01-Aug
8210    31-Oct, 01-Nov
8212    31-May, 01-Jun
8220    31-Mar, 01-Apr
8233    31-May, 01-Jun, 31-Dec
8234    01-Jan
8257    31-May, 01-Jun
8262    31-Mar, 01-Apr
8272    31-Aug, 01-Sep
8280    31-Mar, 01-Apr
8283    31-Mar, 01-Apr
8287    31-Aug, 01-Sep
8288    31-Jul, 01-Aug
8294    31-Jul, 01-Aug
8297    31-Jul, 01-Aug
8309    31-Jul, 01-Aug
8317    31-May, 01-Jun
8321    31-Oct, 01-Nov
8324    31-Oct, 01-Nov
8327    31-Jul, 01-Aug, 31-Oct, 01-Nov
8344    31-Aug, 01-Sep
8375    31-Jul, 01-Aug
8384    31-Oct, 01-Nov
8408    31-Jan, 01-Feb
8435    31-Jul, 01-Aug
8440    31-Dec
8441    01-Jan
8446    31-Dec
8447    01-Jan
8455    31-Aug, 01-Sep, 31-Dec
8456    01-Jan
8470    31-May, 01-Jun
8478    31-Mar, 01-Apr
8483    31-Oct, 01-Nov
8490    31-Mar, 01-Apr
8494    31-Aug, 01-Sep
8497    31-May, 01-Jun
8503    31-May, 01-Jun, 31-Dec
8504    01-Jan
8507    31-Jul, 01-Aug
8520    29-Feb, 01-Mar
8528    31-Jan, 01-Feb
8534    31-Jan, 01-Feb
8540    31-Jan, 01-Feb
8545    31-Aug, 01-Sep
8560    31-May, 01-Jun
8573    31-Oct, 01-Nov
8578    31-May, 01-Jun
8581    31-May, 01-Jun
8587    31-Dec
8588    01-Jan
8589    31-Mar, 01-Apr
8594    31-Jan, 01-Feb, 31-Jul, 01-Aug
8599    31-Aug, 01-Sep
8606    31-Jul, 01-Aug
8611    31-Dec
8612    01-Jan
8621    31-Jul, 01-Aug
8642    31-Jul, 01-Aug
8653    31-Dec
8654    01-Jan
8656    31-Dec
8657    01-Jan, 31-Jan, 01-Feb
8659    31-May, 01-Jun
8660    31-Jan, 01-Feb
8665    31-Aug, 01-Sep
8675    31-Jul, 01-Aug
8686    31-Dec
8687    01-Jan
8694    31-Mar, 01-Apr
8743    31-May, 01-Jun
8750    31-Jan, 01-Feb, 31-Oct, 01-Nov
8755    31-Dec
8756    01-Jan
8758    31-May, 01-Jun
8765    31-Jan, 01-Feb
8769    31-Mar, 01-Apr
8783    31-Jul, 01-Aug
8789    31-Oct, 01-Nov
8807    31-Jan, 01-Feb
8813    31-Jan, 01-Feb
8819    31-Jul, 01-Aug, 31-Oct, 01-Nov
8862    31-Mar, 01-Apr
8866    31-May, 01-Jun
8875    31-Dec
8876    01-Jan
8881    31-Aug, 01-Sep
8884    31-Aug, 01-Sep
8892    29-Feb, 01-Mar
8905    31-Aug, 01-Sep
8906    31-Jul, 01-Aug
8909    31-Jul, 01-Aug
8932    31-Aug, 01-Sep
8935    31-May, 01-Jun
8936    31-Jul, 01-Aug
8948    31-Oct, 01-Nov
8967    31-Mar, 01-Apr
8968    29-Feb, 01-Mar
8977    31-May, 01-Jun
8978    31-Oct, 01-Nov
8985    31-Mar, 01-Apr
8989    31-Dec
8990    01-Jan
9000    31-Mar, 01-Apr
9001    31-Dec
9002    01-Jan
9005    31-Jan, 01-Feb
9009    31-Mar, 01-Apr
9014    31-Jan, 01-Feb
9031    31-Dec
9032    01-Jan
9035    31-Jan, 01-Feb
9068    31-Jan, 01-Feb
9082    31-Aug, 01-Sep
9092    31-Oct, 01-Nov
9094    31-Aug, 01-Sep
9122    31-Jan, 01-Feb
9137    31-Oct, 01-Nov
9139    31-May, 01-Jun
9145    31-Aug, 01-Sep
9146    31-Oct, 01-Nov
9155    31-Jan, 01-Feb
9179    31-Jul, 01-Aug
9194    31-Jul, 01-Aug
9204    31-Mar, 01-Apr
9218    31-Jan, 01-Feb
9244    31-Dec
9245    01-Jan
9249    31-Mar, 01-Apr
9263    31-Jul, 01-Aug
9275    31-Jan, 01-Feb
9290    31-Oct, 01-Nov
9301    31-Aug, 01-Sep
9304    31-Dec
9305    01-Jan
9310    31-Aug, 01-Sep
9313    31-Aug, 01-Sep, 31-Dec
9314    01-Jan
9323    31-Oct, 01-Nov
9326    31-Jul, 01-Aug
9328    31-May, 01-Jun
9330    31-Mar, 01-Apr
9344    31-Jan, 01-Feb
9370    31-May, 01-Jun
9373    31-May, 01-Jun
9392    31-Oct, 01-Nov
9395    31-Oct, 01-Nov
9397    31-Aug, 01-Sep
9415    31-May, 01-Jun
9431    31-Jan, 01-Feb, 31-Oct, 01-Nov
9435    31-Mar, 01-Apr
9447    31-Mar, 01-Apr
9451    31-Aug, 01-Sep
9464    31-Oct, 01-Nov
9467    31-Jul, 01-Aug
9482    31-Jul, 01-Aug
9490    31-Aug, 01-Sep
9519    31-Mar, 01-Apr
9532    29-Feb, 01-Mar
9536    31-Jul, 01-Aug
9547    31-Aug, 01-Sep, 31-Dec
9548    01-Jan, 31-Oct, 01-Nov
9559    31-May, 01-Jun
9566    31-Oct, 01-Nov
9575    31-Jan, 01-Feb
9577    31-May, 01-Jun
9625    31-Aug, 01-Sep
9637    31-May, 01-Jun
9658    31-Aug, 01-Sep
9662    31-Jan, 01-Feb
9673    31-Dec
9674    01-Jan
9693    31-Mar, 01-Apr
9694    31-May, 01-Jun
9696    29-Feb, 01-Mar
9700    31-Aug, 01-Sep
9701    31-Jan, 01-Feb
9731    31-Jan, 01-Feb
9750    31-Mar, 01-Apr
9760    31-Aug, 01-Sep
9765    31-Mar, 01-Apr
9766    31-Dec
9767    01-Jan
9770    31-Jan, 01-Feb
9773    31-Jan, 01-Feb
9780    31-Mar, 01-Apr
9812    31-Jan, 01-Feb
9817    31-Dec
9818    01-Jan
9830    31-Jan, 01-Feb
9832    31-May, 01-Jun
9833    31-Jul, 01-Aug
9838    31-Aug, 01-Sep
9841    31-Aug, 01-Sep
9843    31-Mar, 01-Apr
9850    31-Dec
9851    01-Jan, 31-Jan, 01-Feb
9864    31-Mar, 01-Apr
9868    31-May, 01-Jun
9872    31-Jul, 01-Aug
9876    31-Mar, 01-Apr
9884    31-Oct, 01-Nov
9889    31-May, 01-Jun
9913    31-May, 01-Jun
9925    31-Aug, 01-Sep
9956    31-Jul, 01-Aug
9959    31-Jul, 01-Aug
9968    31-Jan, 01-Feb
9976    31-Dec
9977    01-Jan
9997    31-May, 01-Jun

**edit** revised version, one step shorter, less clunky display routine. I will leave the original version on which Paul commented above.

Code:

001    LBL 'PPD'     Label "Prime Pair Dates"
002    STO 03        Store input year in register 3 
003    SDL 004       multiply by 10000
004    INC X         add 1 to YYYY0000, now have YYYY0001
005    SDR 002       divide by 100 to get in form to allow month to be incremented
006    STO 01        store YYYY00.01 in reg 1
007    #11           enter constant 11
008    STO 04        store 11 in loop counter
009    XEQ 01        check YYYx.1231/YYYY0101, YYYY0131/0201…YYYY1031/1101*
010    DSE 04        decrement counter
011    BACK 002      go back to check next date pair
012    #89           when done checking through 1031/1101, enter constant 89
013    STO+ 01       add 89 to YYYY11.01 to get YYYz00.01
014    XEQ 01        check YYYY.1231/YYYz0101
015    RCL 03        recall input year to display when complete
016    STOP          
017    LBL 01        subroutine to check date pairs for prime
018    INC 01        increment month
019    RCL 01        recall first of month date
020    SDL 02        multiply by 100 to get in proper form
021    PRIME?        is first of month date prime?
022    SKIP 001      if prime, skip to check last of previous month
023    RTN           if not prime, return to get next month
024    SDR 004       divide by 10,000 to get in form to allow date arithmetic
025    1             enter 1
026    +/-           enter -1
027    DAYS+         subtract 1 day from 1st of month to get last of previous month
028    SDL 004       multiply by 10000 to get in proper form
029    PRIME?        is last of prior month date prime?
030    SKIP 001      if prime, skip to display prime date(s)
031    RTN           if not prime, return to get next month
032    XEQ 02        execute display subroutine
033    RCL 01        recall first of month date
034    SDL 002       multiply by 100 to get in proper form for display
035    LBL 02        subroutine to display prime date(s)
036    RCL X         duplicate X value
037    SDR 004       divide year by 10000
038    IP            take integer portion to get year value YYY?
039    x=/=? 03      compare YYY? to input year
040    SKIP 002      if not equal, do not display prime date, it is in wrong year
041    VIEW Y        display date
042    PSE 25        pause to display prime date
043    RTN

**edit 2** I ultimately got around to analyzing Paul's and Eric's versions to see what tips and tricks they used that I likely missed. I discovered similarities, of course. Eric’s posted version, at 50 steps, is a bit longer than the best version I came up with before checking others, but as he noted, it can be easily shortened. A few simple changes (e.g. changing the direct entry of 8800 to CONST #088 SDL 002 and changing the multiplications and divisions by 10000 to SDL 004 and SDR 004) and removing the labels and replacing the GTOs with SKIPs and BACKs reduces it to only 38 steps.

After seeing Eric's program, I first applied his technique of adding 100 to the date instead of dividing by 100 and adding 1 to increment the month. That got my program down to 42 steps. I then applied his technique of using flags to handle dates outside of the test year, and came up with what I believe to be the best I can do, 39 steps, with initialization of date mode and finishing with display of the input year. I prefer this to having the program finish with display of first of the following year, because that looks like an output and could confuse the judges :-) Anyhow, here is that version.

Code:

001    LBL 'PPD'     Label "Prime Pair Dates"
002    Y.MD          Set y.md mode to allow date arithmetic
003    CF ALL        clear all flags to initialize Flag 1 and Flag 2
004    STO 01        Store input year in register 1
005    SDL 004       multiply by 10000
006    INC X         add 1 to YYYY0000, now have YYYY0001
007    STO 02        store YYYY0001 in reg 2
008    #11           enter constant 11
009    STO 03        store 11 in loop counter
010    XEQ 01        check YYYx.1231/YYYY0101, YYYY0131/0201…YYYY1031/1101
011    DSE 03        decrement counter
012    BACK 002      go back to check next date pair
013    SF 02         Set flag 2 to not display YYYz0101
014    #89           when done checking through 1031/1101, 
015    SDL 002       ...enter constant 8900
016    STO+ 02       add 8900 to YYYY1101 to get YYYz0001
017    LBL 01        subroutine to check date pairs for prime
018    # 100         enter constant 100
019    STO+ 02       increment month
020    RCL 02        recall first of month date
021    PRIME?        is first of month date prime?
022    SKIP 003      if prime, skip to check last of previous month
023    SF 01         set flag 1 to display last of prior month if prime after YYYx1231
024    RCL 01        recall input year to display when complete
025    RTN           return for next month or stop.
026    SDR 004       divide prime date by 10,000 to allow date arithmetic
027    1             enter 1
028    +/-           enter -1
029    DAYS+         subtract 1 day from 1st of month to get last of previous month
030    SDL 004       multiply by 10000 to get in proper form
031    PRIME?        is last of prior month date prime?
032    SKIP 001      if prime, we have a prime pair, skip to display prime date(s)
033    BACK 010      if not prime, loop back for next month or to exit
034    FS? 01        Flag 1 clear first to skip display of YYYx1231, set after that
035    PSE 10        pause to display prime date
036    RCL 02        recall first of month date
037    FC? 02        Flag 2 set last iteration to skip display of YYYz0101
038    PSE 10        pause to display prime date
039    BACK 016      loop back to return

**edit 3** A couple more improvements gets it down to 38 steps if the final END is included, while still displaying the input year when the program is done. This could drop to 37 steps if I was satisfied with displaying a zero when done, or 36 steps if the judges were told to ignore the value in the display when the program stops running. This value will either be YYYY1231 or YYYz0101, either of which gives the appearance of an output, so I would prefer to suppress.

Code:

001    LBL 'PPD'     Label "Prime Pair Dates"
002    Y.MD          Set y.md mode to allow date arithmetic
003    CF ALL        clear all flags to initialize Flag 1 and Flag 2
004    STO 00        Store input year in register 0 to display when done.  This step
                     could be eliminated, see comments regarding display at completion
005    SDL 004       multiply by 10000
006    INC X         add 1 to YYYY0000, now have YYYY0001
007    #11           enter constant 11
008    C-STO J       store 11 for loop counter in J and YYYY0001 in K using complex store
009    XEQ 01        check YYYx.1231/YYYY0101, YYYY0131/0201…YYYY1031/1101
010    DSE J         decrement counter
011    BACK 002      go back to check next date pair
012    SF 02         Set flag 2 to not display YYYz0101
013    #89           when done checking through 1031/1101, 
014    SDL 002       ...enter constant 8900
015    STO+ K        add 8900 to YYYY1101 to get YYYz0001
016    LBL 01        subroutine to check date pairs for prime
017    # 100         enter constant 100
018    STO+ K        increment month
019    RCL K         recall first of month date
020    PRIME?        is first of month date prime?
021    SKIP 001      if prime, skip to check last of previous month
022    SKIP 013      if not prime, skip to common loop-back/end point
023    SDR 004       divide prime date by 10,000 to allow date arithmetic
024    1             enter 1
025    +/-           enter -1
026    DAYS+         subtract 1 day from 1st of month to get last of previous month
027    SDL 004       multiply by 10000 to get in proper form
028    PRIME?        is last of prior month date prime?
029    SKIP 001      if prime, we have a prime pair, skip to display prime date(s)
030    SKIP 005      if not prime, skip to common loop-back/end point
031    FS? 01        Flag 1 clear first to skip display of YYYx1231, set after that
032    PSE 10        pause to display prime date
033    RCL K         recall first of month date
034    FC? 02        Flag 2 set last iteration to skip display of YYYz0101
035    PSE 10        pause to display prime date
036    SF 01         set flag 1 to display last of prior month if prime after YYYx1231
037    RCL 00        recall input year to display when complete.  This step could be
                     a CLx or eliminated, see comments regarding display at completion
038    END           loop back or stop when done

[Paul Dale]

(10-06-2014 05:01 PM)Jeff O. Wrote:  I was able to develop a 44 step program that seems as fast as my 83 step version. There may be opportunities to shave a few steps off of that, but I think I'm pretty satisfied at this point.

Interesting program and great use of the 34S features.

One immediate step can be saved -- you don't need the final RTN. A second by omitting the initial label, although that might make reruns harder.


- Pauli

[Jeff O.]

(10-06-2014 09:34 PM)Paul Dale Wrote:  Interesting program and great use of the 34S features.

I kept discovering features that helped. Very early versions had a Leap year determination routine. At one point I wondered if wp34s had a leap year function, that saved a ton of steps. Then discovered the Date arithmetic, which eliminates the need for leap year determination altogether as wp34s knows that the day before 01 March is 29 February in leap years. (I knew it had Prime? all along, I never tried to build a prime checking routine.)

(10-06-2014 09:34 PM)Paul Dale Wrote:  One immediate step can be saved -- you don't need the final RTN. A second by omitting the initial label, although that might make reruns harder.

Never thought to check if END works like RTN, just figured it is the separator for alpha labelled programs. Of course, the manual clearly states “Works like RTN in all other aspects.” So I will accept that reduction, although then it seems like we should count the final END statement, so maybe no reduction. I think the label is needed to make it easy on the judges to run multiple test cases.

Thanks again for your comments.

Jeff