Analysis of zz-www.sudokuoftheday.co.uk-20190220-absurd-base.sdk
Contents
Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019
level: medium
position: 38.....6.5..41.....7...3.......3....6..2...787..6..5......2..5...9.51..7...7.41.6 initial
Autosolve
position: 38..7..6.5.641.7...7..63......1376..6..2.5.787..6..5....7.26.5..69.51..7...7.41.6 autosolve
Pair Reduction Variants
Pair Reduction Analysis
The following important HDP chains were detected:
* DIS # A3: 2,9 => CTR => A3: 1,4 * DIS # F2: 2,9 => CTR => F2: 8 * DIS # B4: 2,9 => CTR => B4: 4,5 * DIS # D3: 8 => CTR => D3: 5,9 * DIS # F2: 2,9 => CTR => F2: 8 * DIS # E6: 4,9 => CTR => E6: 8 * DIS # B5: 4,9 => CTR => B5: 1 * PRF # G5: 4,9 => SOL * DIS # G5: 3 => CTR => G5: 4,9 * DIS # E6: 4 => CTR => E6: 8,9 * DIS # F2: 2 => CTR => F2: 8,9 * DIS # A4: 2,8 => CTR => A4: 4,9 * DIS # D7: 9 => CTR => D7: 3,8 * DIS # E6: 4 => CTR => E6: 8,9 * CNT 14 HDP CHAINS / 43 HYP OPENED
See Appendix: Full HDP Chains for full list of HDP chains.
Pair Reduction
The following important HDP chains were detected:
* DIS # A3: 2,9 => CTR => A3: 1,4 * PRF A3: 1,4 # D3: 5,9 => SOL * STA A3: 1,4 + D3: 5,9 * CNT 2 HDP CHAINS / 2 HYP OPENED
See Appendix: Full HDP Chains for full list of HDP chains.
Details
Positions
| 38.....6.5..41.....7...3.......3....6..2...787..6..5......2..5...9.51..7...7.41.6 | initial |
| 38..7..6.5.641.7...7..63......1376..6..2.5.787..6..5....7.26.5..69.51..7...7.41.6 | autosolve |
| 381972465596418732472563891958137624613245978724689513147826359869351247235794186 | solved |
Classification
level: medium
Pairing Analysis
-------------------------------------------------- * PAIRS (10) B2: 2,9 D1: 5,9 F1: 2,9 C4: 5,8 E5: 4,9 F6: 8,9 A9: 2,8 C9: 5,8 D8: 3,8 E9: 8,9 -------------------------------------------------- * CONSTRAINT PAIRS (AUTO SOLVE) B5,C5: 1.. / B5 = 1 => 12 pairs (_) / C5 = 1 => 0 pairs (X) H6,I6: 1.. / H6 = 1 => 12 pairs (_) / I6 = 1 => 13 pairs (_) A7,B7: 1.. / A7 = 1 => 12 pairs (_) / B7 = 1 => 0 pairs (X) C1,I1: 1.. / C1 = 1 => 13 pairs (_) / I1 = 1 => 11 pairs (_) A3,A7: 1.. / A3 = 1 => 0 pairs (X) / A7 = 1 => 12 pairs (_) B5,B7: 1.. / B5 = 1 => 12 pairs (_) / B7 = 1 => 0 pairs (X) H3,H6: 1.. / H3 = 1 => 13 pairs (_) / H6 = 1 => 12 pairs (_) F1,F2: 2.. / F1 = 2 => 12 pairs (_) / F2 = 2 => 0 pairs (X) H2,I2: 3.. / H2 = 3 => 17 pairs (_) / I2 = 3 => 11 pairs (_) C5,C6: 3.. / C5 = 3 => 0 pairs (*) / C6 = 3 => 0 pairs (X) B7,B9: 3.. / B7 = 3 => 0 pairs (X) / B9 = 3 => 10 pairs (_) D7,D8: 3.. / D7 = 3 => 15 pairs (_) / D8 = 3 => 10 pairs (_) C5,G5: 3.. / C5 = 3 => 0 pairs (*) / G5 = 3 => 0 pairs (X) B9,H9: 3.. / B9 = 3 => 10 pairs (_) / H9 = 3 => 0 pairs (X) E5,E6: 4.. / E5 = 4 => 14 pairs (_) / E6 = 4 => 0 pairs (X) D1,D3: 5.. / D1 = 5 => 10 pairs (_) / D3 = 5 => 0 pairs (*) I1,I3: 5.. / I1 = 5 => 0 pairs (*) / I3 = 5 => 0 pairs (X) B4,C4: 5.. / B4 = 5 => 9 pairs (_) / C4 = 5 => 0 pairs (X) B9,C9: 5.. / B9 = 5 => 0 pairs (X) / C9 = 5 => 9 pairs (_) D1,I1: 5.. / D1 = 5 => 10 pairs (_) / I1 = 5 => 0 pairs (*) D3,I3: 5.. / D3 = 5 => 0 pairs (*) / I3 = 5 => 0 pairs (X) B4,B9: 5.. / B4 = 5 => 9 pairs (_) / B9 = 5 => 0 pairs (X) C4,C9: 5.. / C4 = 5 => 0 pairs (X) / C9 = 5 => 9 pairs (_) F2,D3: 8.. / F2 = 8 => 14 pairs (_) / D3 = 8 => 0 pairs (X) A4,C4: 8.. / A4 = 8 => 0 pairs (X) / C4 = 8 => 9 pairs (_) E6,F6: 8.. / E6 = 8 => 14 pairs (_) / F6 = 8 => 0 pairs (X) F2,H2: 8.. / F2 = 8 => 14 pairs (_) / H2 = 8 => 0 pairs (X) C4,C9: 8.. / C4 = 8 => 9 pairs (_) / C9 = 8 => 0 pairs (X) E6,E9: 8.. / E6 = 8 => 14 pairs (_) / E9 = 8 => 0 pairs (X) F2,F6: 8.. / F2 = 8 => 14 pairs (_) / F6 = 8 => 0 pairs (X) B2,A3: 9.. / B2 = 9 => 15 pairs (_) / A3 = 9 => 0 pairs (X) D7,E9: 9.. / D7 = 9 => 0 pairs (X) / E9 = 9 => 14 pairs (_) E9,H9: 9.. / E9 = 9 => 14 pairs (_) / H9 = 9 => 0 pairs (X) A3,A4: 9.. / A3 = 9 => 0 pairs (X) / A4 = 9 => 15 pairs (_) * DURATION: 0:00:45.118837 START: 03:52:12.645800 END: 03:52:57.764637 2019-05-01 * CP COUNT: (34) * SOLUTION FOUND -------------------------------------------------- * PREPARE PR GRAPH * PAIR REDUCTION .. * LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B2,C4,C9,D1,D8,E5,E9,F1,F6) * 38..7..6.5.641.7...7..63......1376..6..2.5.787..6..5....7.26.5..69.51..7...7.41.6 * PAIR B2: 2,9 BLK 1 A3: 2,9,1,4 # reduction candidate for 2,9 A3: 2,9 => CTR * 38..7..6.52641.7..97..63....581376..6132.5.787926.85..147.26.59.69.51..7.357.41.6 A3: 1,4 # 16 pairs * PAIR B2: 2,9 ROW 2 F2: 2,9,8 # reduction candidate for 2,9 F2: 2,9 => CTR * 38157.46.5.641.78397.863..5..81376..6..2.5.787..6.8531..7926354469351827235784196 F2: 8 # 14 pairs H2: 2,9,3,8 # reduction candidate for 2,9 H2: 2,9 # 16 pairs I2: 2,9,3 # reduction candidate for 2,9 I2: 2,9 # 17 pairs * PAIR B2: 2,9 COL B B4: 2,9,4,5 # reduction candidate for 2,9 B4: 2,9 => CTR * 38..7..6.5.641.7.3.7..63...8.51376..6..2453787.36895...37826.5..69351..7258794136 B4: 4,5 # 11 pairs B6: 2,9,4 # reduction candidate for 2,9 B6: 2,9 # 14 pairs * PAIR D1: 5,9 BLK 2 D3: 5,9,8 # reduction candidate for 5,9 D3: 8 => CTR * 38157.46.5.641.78397.863..5..81376..6..2.5.787..6.8531..7926354469351827235784196 D3: 5,9 # 14 pairs * PAIR D1: 5,9 ROW 1 I1: 5,9,1,2,4 # reduction candidate for 5,9 I1: 5,9 # 15 pairs I1: 1,2,4 # 10 pairs * PAIR F1: 2,9 BLK 2 F2: 2,9,8 # reduction candidate for 2,9 F2: 2,9 => CTR * 38157.46.5.641.78397.863..5..81376..6..2.5.787..6.8531..7926354469351827235784196 F2: 8 # 14 pairs * PAIR F1: 2,9 ROW 1 G1: 2,9,4 # reduction candidate for 2,9 G1: 2,9 # 13 pairs I1: 2,9,1,4,5 # reduction candidate for 2,9 I1: 2,9 # 15 pairs * PAIR E5: 4,9 BLK 5 E6: 4,9,8 # reduction candidate for 4,9 E6: 4,9 => CTR * 38.57..6.5.641.783.7.863..59581376426..2.5.787..6.8531817926354469351827235784196 E6: 8 # 14 pairs * PAIR E5: 4,9 ROW 5 B5: 4,9,1 # reduction candidate for 4,9 B5: 4,9 => CTR * 38..7..615.641.7..17..63..59581376..641295378723648519.17926.53.69351..7.35784196 B5: 1 # 12 pairs G5: 4,9,3 # reduction candidate for 4,9 G5: 4,9 => SOLVED * 381972465596418732472563891958137624613245978724689513147826359869351247235794186 G5: 3 => CTR * 38..7..6.59641.7...7..63...9.81376..6..2953787.36485....7926.5..69351..7..5784196 * PAIR F6: 8,9 BLK 5 E6: 8,9,4 # reduction candidate for 8,9 E6: 4 => CTR * 38.57..6.5.641.783.7.863..59581376426412953787..6485....7926.54469351827235784196 E6: 8,9 # 14 pairs * PAIR F6: 8,9 COL F F2: 8,9,2 # reduction candidate for 8,9 F2: 2 => CTR * 38.579.6.596412783.7.8639.59.81376..6..295.787..64853...7.26.5..69351..7...784196 F2: 8,9 # 12 pairs * PAIR A9: 2,8 BLK 7 A8: 2,8,4 # reduction candidate for 2,8 A8: 4 # 14 pairs A8: 2,8 # 13 pairs * PAIR A9: 2,8 ROW 9 H9: 2,8,3,9 # reduction candidate for 2,8 H9: 2,8 # 15 pairs H9: 3,9 # 12 pairs * PAIR A9: 2,8 COL A A4: 2,8,4,9 # reduction candidate for 2,8 A4: 2,8 => CTR * 38..7..6.52641.7..97..63......1376..61.2.5.787.26..5..137.26.5.469351..7258794136 A4: 4,9 # 10 pairs * PAIR D8: 3,8 BLK 8 D7: 3,8,9 # reduction candidate for 3,8 D7: 9 => CTR * 38157.46.5.641.78397.863..5.581376..6..2.5.787..6.8531..7926354469351827235784196 D7: 3,8 # 14 pairs * PAIR D8: 3,8 ROW 8 G8: 3,8,2,4 # reduction candidate for 3,8 G8: 3,8 # 15 pairs H8: 3,8,2,4 # reduction candidate for 3,8 H8: 3,8 # 13 pairs * PAIR E9: 8,9 BLK 8 D7: 8,9,3 # reduction candidate for 8,9 D7: 3 # 15 pairs D7: 8,9 # 10 pairs * PAIR E9: 8,9 ROW 9 H9: 8,9,2,3 # reduction candidate for 8,9 H9: 2,3 # 17 pairs H9: 8,9 # 11 pairs * PAIR E9: 8,9 COL E E6: 8,9,4 # reduction candidate for 8,9 E6: 4 => CTR * 38.57..6.5.641.783.7.863..59581376426412953787..6485....7926.54469351827235784196 E6: 8,9 # 14 pairs * INCONCLUSIVE * SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190220-absurd-base-pr-000.dot * REASONING * DIS # A3: 2,9 => CTR => A3: 1,4 * DIS # F2: 2,9 => CTR => F2: 8 * DIS # B4: 2,9 => CTR => B4: 4,5 * DIS # D3: 8 => CTR => D3: 5,9 * DIS # F2: 2,9 => CTR => F2: 8 * DIS # E6: 4,9 => CTR => E6: 8 * DIS # B5: 4,9 => CTR => B5: 1 * PRF # G5: 4,9 => SOL * DIS # G5: 3 => CTR => G5: 4,9 * DIS # E6: 4 => CTR => E6: 8,9 * DIS # F2: 2 => CTR => F2: 8,9 * DIS # A4: 2,8 => CTR => A4: 4,9 * DIS # D7: 9 => CTR => D7: 3,8 * DIS # E6: 4 => CTR => E6: 8,9 * CNT 14 HDP CHAINS / 43 HYP OPENED -------------------------------------------------- * PREPARE PR GRAPH * PAIR REDUCTION .. * LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B2,C4,C9,D1,D8,E5,E9,F1,F6) * 38..7..6.5.641.7...7..63......1376..6..2.5.787..6..5....7.26.5..69.51..7...7.41.6 * PAIR B2: 2,9 BLK 1 A3: 2,9,1,4 # reduction candidate for 2,9 A3: 2,9 => CTR * 38..7..6.52641.7..97..63....581376..6132.5.787926.85..147.26.59.69.51..7.357.41.6 * PAIR D1: 5,9 BLK 2 D3: 5,9,8 # reduction candidate for 5,9 D3: 5,9 => SOLVED * 381972465596418732472563891958137624613245978724689513147826359869351247235794186 * DURATION: 0:00:03.410558 START: 03:53:29.441004 END: 03:53:32.851562 2019-05-01 * SOLUTION FOUND * SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190220-absurd-base-pr-001.dot * REASONING * DIS # A3: 2,9 => CTR => A3: 1,4 * PRF A3: 1,4 # D3: 5,9 => SOL * STA A3: 1,4 + D3: 5,9 * CNT 2 HDP CHAINS / 2 HYP OPENED
Header Info
http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019, 20190220, absurd
Solution
position: 381972465596418732472563891958137624613245978724689513147826359869351247235794186 solved
See section Pair Reduction for the HDP chains leading to this result.
Appendix: Full HDP Chains
A1. Pair Reduction Analysis
Full list of HDP chains traversed:
* DIS # A3: 2,9 => CTR => A3: 1,4 * INC # A3: 1,4 => UNS * DIS # F2: 2,9 => CTR => F2: 8 * INC # F2: 8 => UNS * INC # H2: 2,9 => UNS * INC # I2: 2,9 => UNS * DIS # B4: 2,9 => CTR => B4: 4,5 * INC # B4: 4,5 => UNS * INC # B6: 2,9 => UNS * INC # D3: 5,9 => UNS * DIS # D3: 8 => CTR => D3: 5,9 * INC # I1: 5,9 => UNS * INC # I1: 1,2,4 => UNS * DIS # F2: 2,9 => CTR => F2: 8 * INC # F2: 8 => UNS * INC # G1: 2,9 => UNS * INC # I1: 2,9 => UNS * DIS # E6: 4,9 => CTR => E6: 8 * INC # E6: 8 => UNS * DIS # B5: 4,9 => CTR => B5: 1 * INC # B5: 1 => UNS * PRF # G5: 4,9 => SOL * DIS # G5: 3 => CTR => G5: 4,9 * INC # E6: 8,9 => UNS * DIS # E6: 4 => CTR => E6: 8,9 * INC # F2: 8,9 => UNS * DIS # F2: 2 => CTR => F2: 8,9 * INC # A8: 2,8 => UNS * INC # A8: 4 => UNS * INC # H9: 2,8 => UNS * INC # H9: 3,9 => UNS * DIS # A4: 2,8 => CTR => A4: 4,9 * INC # A4: 4,9 => UNS * INC # D7: 3,8 => UNS * DIS # D7: 9 => CTR => D7: 3,8 * INC # G8: 3,8 => UNS * INC # H8: 3,8 => UNS * INC # D7: 8,9 => UNS * INC # D7: 3 => UNS * INC # H9: 8,9 => UNS * INC # H9: 2,3 => UNS * INC # E6: 8,9 => UNS * DIS # E6: 4 => CTR => E6: 8,9 * CNT 43 HDP CHAINS / 43 HYP OPENED
A2. Pair Reduction
Full list of HDP chains traversed:
* DIS # A3: 2,9 => CTR => A3: 1,4 * PRF A3: 1,4 # D3: 5,9 => SOL * STA A3: 1,4 + D3: 5,9 * CNT 2 HDP CHAINS / 2 HYP OPENED