(25) N-Queens - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (25) N-Queens (/thread-18092.html) (25) N-Queens - Thomas Klemm - 03-02-2022 01:20 AM References The program is based on the flowcharts that are linked in Dave Britten's solution. But I had to make some changes: the number format is \(0.a_1 a_2 \cdots a_8\) the indexes \(m_0\) and \(m_1\) are decremented so we can use comparison with \(0\) the number \(10\) is kept as a constant in register \(m_6\) storage arithmetic helped to save some steps Registers 0: # of old queens 1: New queen 2: Old queens 3: Chopping block 4: i counter 5: n size of board 6: 10 as constant Initialization and Run CLEAR REG FIX 8 8 STO 0 STO 5 10 STO 6 GTO 13 R/S Solution After about 40 minutes this result is shown: 0.57263148 This corresponds to the following setup:     5 7 2 6 3 1 4 8 8: | | | | | | | |#| 7: | |#| | | | | | | 6: | | | |#| | | | | 5: |#| | | | | | | | 4: | | | | | | |#| | 3: | | | | |#| | | | 2: | | |#| | | | | | 1: | | | | | |#| | | The next solutions will be shown after starting the program again with R/S. However for now it will not detect the end. There simply was no memory left to do so. Program The program can be used in this HP-25C emulator. Code: ```01: 24 01    : RCL 1 02: 23 51 02 : STO + 2 03: 24 06    : RCL 6 04: 23 71 02 : STO / 2 05: 01       : 1 06: 23 41 00 : STO - 0 07: 24 00    : RCL 0 08: 15 61    : g x<>0 09: 13 13    : GTO 13 10: 24 02    : RCL 2 11: 74       : R/S 12: 13 36    : GTO 36 13: 24 05    : RCL 5 14: 23 01    : STO 1 15: 24 02    : RCL 2 16: 23 03    : STO 3 17: 34       : CLx 18: 23 04    : STO 4 19: 01       : 1 20: 23 51 04 : STO + 4 21: 24 06    : RCL 6 22: 23 61 03 : STO * 3 23: 24 03    : RCL 3 24: 15 71    : g x=0 25: 13 01    : GTO 01 26: 14 01    : f INT 27: 23 41 03 : STO - 3 28: 24 01    : RCL 1 29: 14 71    : f x=y 30: 13 36    : GTO 36 31: 41       : - 32: 15 03    : g ABS 33: 24 04    : RCL 4 34: 14 61    : f x<>y 35: 13 19    : GTO 19 36: 01       : 1 37: 23 41 01 : STO - 1 38: 24 01    : RCL 1 39: 15 61    : g x<>0 40: 13 15    : GTO 15 41: 01       : 1 42: 23 51 00 : STO + 0 43: 24 06    : RCL 6 44: 23 61 02 : STO * 2 45: 24 02    : RCL 2 46: 14 01    : f INT 47: 23 41 02 : STO - 2 48: 23 01    : STO 1 49: 13 36    : GTO 36``` RE: (25) N-Queens - Dave Britten - 03-02-2022 01:31 AM Wow, impressive! I took a very brief stab at doing this, but I was about 20 steps over the limit, with no obvious way to trim any more fat.