[VA] Short & Sweet Math Challenge #25 "San Valentin's Special: Weird Math"

[Gerson W. Barbosa]

#6

Longer, but faster: 17.547 seconds on the HP 50g (previously 29.952 seconds for argument = 5000)

« DUPDUP 4 * SWAP LN SQ / 3 XROOT 3 * CEIL { } 1 DUP2 ROT 5 ROLL
START NEXTPRIME + LASTARG NIP
NEXT DROP SQ DUP SIZE 2 SWAP
FOR i 1 OVER SIZE 1 + i -
FOR j DUP j DUP i + 1 - SUB ∑LIST 4 PICK OVER ≥ { ROT + SWAP } { DROP } IFTE
NEXT
NEXT + SORT REVLIST
WHILE DUP HEAD PICK3 >
REPEAT TAIL
END REVLIST NIP
»

Checksum: # 5E22h
Bytes: 238.5 bytes


This is closer to the HP-75C version, except for the prime list:

« DUPDUP 4 * SWAP LN SQ / 3 XROOT 3 * CEIL { } 1 DUP2 ROT 5 ROLL
START NEXTPRIME + LASTARG NIP
NEXT DROP SQ DUP SIZE 1 SWAP
FOR i 1 OVER SIZE 1 + i -
FOR j DUP j DUP i + 1 - SUB DUP SIZE 1 - NOT { 0 + } IFT ∑LIST 4 PICK OVER ≥ { ROT + SWAP } { DROP } IFTE
NEXT
NEXT ROT DROP2 SORT
»

Checksum: # A346h
Bytes: 226.5 bytes
21.510 seconds

As a comparison, the BASIC program takes about 96 seconds on the HP-75C. Also, the BASIC program is limited to arguments up to 5492, unless of course the prime list is extended.