Analysis of zz-www.sudokuoftheday.co.uk-20190222-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: .2.....6.61..4......4...1...7..3.64.2....4.7....7.6.3..41..5....8....31....6.9..7 initial
Autosolve
position: 32...1.6461..43...8.4.671.317..386422631.4.7.4.8726.31741385..6986472315532619487 autosolve
Pair Reduction Variants
Pair Reduction Analysis
The following important HDP chains were detected:
* PRF # D1: 5,9 => SOL * PRF # D1: 5,9 => SOL * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G5: 8,9 => CTR => G5: 5 * PRF # G5: 5 => SOL * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G2: 2,9 => CTR => G2: 7,8 * PRF # H2: 2,9 => SOL * CNT 8 HDP CHAINS / 31 HYP OPENED
See Appendix: Full HDP Chains for full list of HDP chains.
Pair Reduction
The following important HDP chains were detected:
* PRF # D1: 5,9 => SOL * STA D1: 5,9 * CNT 1 HDP CHAINS / 5 HYP OPENED
See Appendix: Full HDP Chains for full list of HDP chains.
Details
Positions
| .2.....6.61..4......4...1...7..3.64.2....4.7....7.6.3..41..5....8....31....6.9..7 | initial |
| 32...1.6461..43...8.4.671.317..386422631.4.7.4.8726.31741385..6986472315532619487 | autosolve |
| 327951864615843729894267153179538642263194578458726931741385296986472315532619487 | solved |
Classification
level: medium
Pairing Analysis
-------------------------------------------------- * PAIRS (11) B3: 5,9 E1: 5,9 I2: 8,9 C4: 5,9 B6: 5,9 D4: 5,9 E5: 5,9 I5: 8,9 G6: 5,9 G7: 2,9 H7: 2,9 -------------------------------------------------- * CONSTRAINT PAIRS (AUTO SOLVE) D2,D3: 2.. / D2 = 2 => 12 pairs (_) / D3 = 2 => 12 pairs (_) G7,H7: 2.. / G7 = 2 => 11 pairs (_) / H7 = 2 => 0 pairs (X) D3,H3: 2.. / D3 = 2 => 12 pairs (_) / H3 = 2 => 12 pairs (_) G2,G7: 2.. / G2 = 2 => 0 pairs (X) / G7 = 2 => 11 pairs (_) H2,H3: 5.. / H2 = 5 => 13 pairs (_) / H3 = 5 => 0 pairs (*) C4,B6: 5.. / C4 = 5 => 0 pairs (X) / B6 = 5 => 0 pairs (_) D4,E5: 5.. / D4 = 5 => 0 pairs (*) / E5 = 5 => 0 pairs (X) G5,G6: 5.. / G5 = 5 => 0 pairs (*) / G6 = 5 => 0 pairs (X) C4,D4: 5.. / C4 = 5 => 0 pairs (X) / D4 = 5 => 0 pairs (_) E5,G5: 5.. / E5 = 5 => 0 pairs (X) / G5 = 5 => 0 pairs (_) B6,G6: 5.. / B6 = 5 => 0 pairs (*) / G6 = 5 => 0 pairs (X) B3,B6: 5.. / B3 = 5 => 0 pairs (X) / B6 = 5 => 0 pairs (_) E1,E5: 5.. / E1 = 5 => 0 pairs (*) / E5 = 5 => 0 pairs (X) C1,C2: 7.. / C1 = 7 => 14 pairs (_) / C2 = 7 => 12 pairs (_) G1,G2: 7.. / G1 = 7 => 12 pairs (_) / G2 = 7 => 14 pairs (_) C1,G1: 7.. / C1 = 7 => 14 pairs (_) / G1 = 7 => 12 pairs (_) C2,G2: 7.. / C2 = 7 => 12 pairs (_) / G2 = 7 => 14 pairs (_) D1,D2: 8.. / D1 = 8 => 12 pairs (_) / D2 = 8 => 0 pairs (*) G5,I5: 8.. / G5 = 8 => 0 pairs (X) / I5 = 8 => 13 pairs (_) D1,G1: 8.. / D1 = 8 => 12 pairs (_) / G1 = 8 => 0 pairs (*) I2,I5: 8.. / I2 = 8 => 0 pairs (X) / I5 = 8 => 13 pairs (_) C4,B6: 9.. / C4 = 9 => 0 pairs (*) / B6 = 9 => 0 pairs (X) D4,E5: 9.. / D4 = 9 => 0 pairs (X) / E5 = 9 => 0 pairs (_) G7,H7: 9.. / G7 = 9 => 0 pairs (X) / H7 = 9 => 11 pairs (_) C4,D4: 9.. / C4 = 9 => 0 pairs (*) / D4 = 9 => 0 pairs (X) B6,G6: 9.. / B6 = 9 => 0 pairs (X) / G6 = 9 => 0 pairs (_) B3,B6: 9.. / B3 = 9 => 0 pairs (*) / B6 = 9 => 0 pairs (X) E1,E5: 9.. / E1 = 9 => 0 pairs (X) / E5 = 9 => 0 pairs (_) I2,I5: 9.. / I2 = 9 => 13 pairs (_) / I5 = 9 => 0 pairs (X) * DURATION: 0:00:48.156817 START: 03:55:21.966493 END: 03:56:10.123310 2019-05-01 * CP COUNT: (29) * SOLUTION FOUND -------------------------------------------------- * PREPARE PR GRAPH * PAIR REDUCTION .. * LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B3,B6,C4,D4,E1,E5,G6,G7,H7,I2,I5) * 32...1.6461..43...8.4.671.317..386422631.4.7.4.8726.31741385..6986472315532619487 * PAIR B3: 5,9 BLK 1 C1: 5,9,7 # reduction candidate for 5,9 C1: 5,9 # 12 pairs C2: 5,9,7 # reduction candidate for 5,9 C2: 5,9 # 14 pairs * PAIR B3: 5,9 ROW 3 D3: 5,9,2 # reduction candidate for 5,9 D3: 5,9 # 12 pairs H3: 5,9,2 # reduction candidate for 5,9 H3: 5,9 # 12 pairs * PAIR E1: 5,9 BLK 2 D1: 5,9,8 # reduction candidate for 5,9 D1: 5,9 => SOLVED * 327951864615843729894267153179538642263194578458726931741385296986472315532619487 D1: 8 # 12 pairs D2: 5,9,2,8 # reduction candidate for 5,9 D2: 5,9 # 14 pairs D3: 5,9,2 # reduction candidate for 5,9 D3: 5,9 # 12 pairs * PAIR E1: 5,9 ROW 1 C1: 5,9,7 # reduction candidate for 5,9 C1: 7 # 14 pairs C1: 5,9 # 12 pairs * PAIR I2: 8,9 BLK 3 G1: 8,9,7 # reduction candidate for 8,9 G1: 8,9 # 14 pairs G2: 8,9,2,7 # reduction candidate for 8,9 G2: 8,9 # 14 pairs * PAIR I2: 8,9 ROW 2 D2: 8,9,2,5 # reduction candidate for 8,9 D2: 8,9 # 17 pairs D2: 2,5 # 13 pairs * PAIR C4: 5,9 COL C C1: 5,9,7 # reduction candidate for 5,9 C1: 5,9 # 12 pairs C2: 5,9,7 # reduction candidate for 5,9 C2: 5,9 # 14 pairs * PAIR D4: 5,9 COL D D1: 5,9,8 # reduction candidate for 5,9 D1: 5,9 => SOLVED * 327951864615843729894267153179538642263194578458726931741385296986472315532619487 D1: 8 # 12 pairs D2: 5,9,2,8 # reduction candidate for 5,9 D2: 5,9 # 14 pairs D3: 5,9,2 # reduction candidate for 5,9 D3: 5,9 # 12 pairs * PAIR E5: 5,9 ROW 5 G5: 5,9,8 # reduction candidate for 5,9 G5: 8 => CTR * 32.89176461..43...8.4.671.317..38642263154879498726531741385..6986472315532619487 G5: 5,9 # 13 pairs * PAIR I5: 8,9 BLK 6 G5: 8,9,5 # reduction candidate for 8,9 G5: 8,9 => CTR * 32759186461..43...854267193175938642263154.79498726531741385926986472315532619487 G5: 5 => SOLVED * 327951864615843729894267153179538642263194578458726931741385296986472315532619487 * PAIR G6: 5,9 BLK 6 G5: 5,9,8 # reduction candidate for 5,9 G5: 8 => CTR * 32.89176461..43...8.4.671.317..38642263154879498726531741385..6986472315532619487 G5: 5,9 # 13 pairs * PAIR G7: 2,9 COL G G2: 2,9,7,8 # reduction candidate for 2,9 G2: 2,9 => CTR * 329851764617.43..88.4.671.317..386422631.4879498726531741385..6986472315532619487 G2: 7,8 # 12 pairs * PAIR H7: 2,9 COL H H2: 2,9,5 # reduction candidate for 2,9 H2: 2,9 => SOLVED * 327951864615843729894267153179538642263194578458726931741385296986472315532619487 H2: 5 # 13 pairs H3: 2,9,5 # reduction candidate for 2,9 H3: 2,9 # 13 pairs * INCONCLUSIVE * SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190222-absurd-base-pr-000.dot * REASONING * PRF # D1: 5,9 => SOL * PRF # D1: 5,9 => SOL * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G5: 8,9 => CTR => G5: 5 * PRF # G5: 5 => SOL * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G2: 2,9 => CTR => G2: 7,8 * PRF # H2: 2,9 => SOL * CNT 8 HDP CHAINS / 31 HYP OPENED -------------------------------------------------- * PREPARE PR GRAPH * PAIR REDUCTION .. * LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B3,B6,C4,D4,E1,E5,G6,G7,H7,I2,I5) * 32...1.6461..43...8.4.671.317..386422631.4.7.4.8726.31741385..6986472315532619487 * PAIR B3: 5,9 BLK 1 C1: 5,9,7 # reduction candidate for 5,9 C1: 5,9 # 12 pairs C2: 5,9,7 # reduction candidate for 5,9 C2: 5,9 # 14 pairs * PAIR B3: 5,9 ROW 3 D3: 5,9,2 # reduction candidate for 5,9 D3: 5,9 # 12 pairs H3: 5,9,2 # reduction candidate for 5,9 H3: 5,9 # 12 pairs * PAIR E1: 5,9 BLK 2 D1: 5,9,8 # reduction candidate for 5,9 D1: 5,9 => SOLVED * 327951864615843729894267153179538642263194578458726931741385296986472315532619487 * DURATION: 0:00:05.451757 START: 03:56:39.586245 END: 03:56:45.038002 2019-05-01 * SOLUTION FOUND * SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190222-absurd-base-pr-001.dot * REASONING * PRF # D1: 5,9 => SOL * STA D1: 5,9 * CNT 1 HDP CHAINS / 5 HYP OPENED
Header Info
http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019, 20190222, absurd
Solution
position: 327951864615843729894267153179538642263194578458726931741385296986472315532619487 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:
* INC # C1: 5,9 => UNS * INC # C2: 5,9 => UNS * INC # D3: 5,9 => UNS * INC # H3: 5,9 => UNS * PRF # D1: 5,9 => SOL * INC # D1: 8 => UNS * INC # D2: 5,9 => UNS * INC # D3: 5,9 => UNS * INC # C1: 5,9 => UNS * INC # C1: 7 => UNS * INC # G1: 8,9 => UNS * INC # G2: 8,9 => UNS * INC # D2: 8,9 => UNS * INC # D2: 2,5 => UNS * INC # C1: 5,9 => UNS * INC # C2: 5,9 => UNS * PRF # D1: 5,9 => SOL * INC # D1: 8 => UNS * INC # D2: 5,9 => UNS * INC # D3: 5,9 => UNS * INC # G5: 5,9 => UNS * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G5: 8,9 => CTR => G5: 5 * PRF # G5: 5 => SOL * INC # G5: 5,9 => UNS * DIS # G5: 8 => CTR => G5: 5,9 * DIS # G2: 2,9 => CTR => G2: 7,8 * INC # G2: 7,8 => UNS * PRF # H2: 2,9 => SOL * INC # H2: 5 => UNS * INC # H3: 2,9 => UNS * CNT 31 HDP CHAINS / 31 HYP OPENED
A2. Pair Reduction
Full list of HDP chains traversed:
* INC # C1: 5,9 => UNS * INC # C2: 5,9 => UNS * INC # D3: 5,9 => UNS * INC # H3: 5,9 => UNS * PRF # D1: 5,9 => SOL * STA D1: 5,9 * CNT 5 HDP CHAINS / 5 HYP OPENED