Analysis of xx-top95-082-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..........5724...98....947...9..3...5..9..12...3.1.9...6....25....56.....7......6 initial

Autosolve

position: ..........5724...98....947...9..3...5..9..123..3.1.9...6....25....56.....75.....6 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B4: 4,8 => CTR => B4: 1,2
* DIS # B6: 4,8 => CTR => B6: 2
* DIS # F5: 4,8 => CTR => F5: 6,7
* DIS # F5: 7,8 => CTR => F5: 4,6
* CNT   4 HDP CHAINS /  22 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* DIS # B4: 4,8 => CTR => B4: 1,2
* DIS B4: 1,2 # B6: 4,8 => CTR => B6: 2
* DIS B4: 1,2 + B6: 2 # C5: 6 => CTR => C5: 4,8
* PRF B4: 1,2 + B6: 2 + C5: 4,8 # B8: 9 => SOL
* STA B4: 1,2 + B6: 2 + C5: 4,8 + B8: 9
* CNT   4 HDP CHAINS /   9 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Details

Positions

..........5724...98....947...9..3...5..9..12...3.1.9...6....25....56.....7......6 initial
..........5724...98....947...9..3...5..9..123..3.1.9...6....25....56.....75.....6 autosolve
946731582157248639832659471719423865584976123623815947461397258398562714275184396 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (6)
E3: 3,5
B5: 4,8
E4: 2,5
E5: 7,8
F6: 2,5
G9: 3,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A4,B4: 1.. / A4 = 1  =>  0 pairs (X) / B4 = 1  =>  7 pairs (_)
I1,I3: 2.. / I1 = 2  =>  7 pairs (_) / I3 = 2  =>  6 pairs (_)
E4,F6: 2.. / E4 = 2  =>  4 pairs (_) / F6 = 2  =>  0 pairs (X)
E4,E9: 2.. / E4 = 2  =>  4 pairs (_) / E9 = 2  =>  0 pairs (X)
E4,F6: 5.. / E4 = 5  =>  0 pairs (X) / F6 = 5  =>  4 pairs (_)
E3,I3: 5.. / E3 = 5  =>  4 pairs (_) / I3 = 5  =>  0 pairs (X)
F6,I6: 5.. / F6 = 5  =>  4 pairs (_) / I6 = 5  =>  0 pairs (X)
F1,F6: 5.. / F1 = 5  =>  0 pairs (X) / F6 = 5  =>  4 pairs (_)
G1,G4: 5.. / G1 = 5  =>  4 pairs (_) / G4 = 5  =>  6 pairs (_)
C3,D3: 6.. / C3 = 6  =>  0 pairs (X) / D3 = 6  => 22 pairs (_)
C5,F5: 6.. / C5 = 6  =>  0 pairs (X) / F5 = 6  => 19 pairs (_)
A4,A6: 7.. / A4 = 7  =>  5 pairs (_) / A6 = 7  =>  6 pairs (_)
E5,F5: 7.. / E5 = 7  =>  5 pairs (_) / F5 = 7  =>  0 pairs (X)
A6,I6: 7.. / A6 = 7  =>  6 pairs (_) / I6 = 7  =>  5 pairs (_)
D1,D7: 7.. / D1 = 7  =>  6 pairs (_) / D7 = 7  =>  8 pairs (_)
G4,G8: 7.. / G4 = 7  => 11 pairs (_) / G8 = 7  =>  6 pairs (_)
A1,B1: 9.. / A1 = 9  =>  8 pairs (_) / B1 = 9  =>  6 pairs (_)
E7,E9: 9.. / E7 = 9  =>  6 pairs (_) / E9 = 9  =>  4 pairs (_)
H8,H9: 9.. / H8 = 9  =>  6 pairs (_) / H9 = 9  =>  6 pairs (_)
A7,E7: 9.. / A7 = 9  =>  4 pairs (_) / E7 = 9  =>  6 pairs (_)
B1,B8: 9.. / B1 = 9  =>  6 pairs (_) / B8 = 9  =>  8 pairs (_)
* DURATION: 0:00:23.353043  START: 00:50:14.756468  END: 00:50:38.109511 2017-05-04
* CP COUNT: (21)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B5,E3,E4,E5,F6,G9)
* ..........5724...98....947...9..3...5..9..123..3.1.9...6....25....56.....75.....6
* PAIR E3: 3,5 BLK 2
E1: 3,5,7,8                              # reduction candidate for 3,5
E1: 7,8                                  #  8 pairs
E1: 3,5                                  #  7 pairs
* PAIR B5: 4,8 BLK 4
B4: 4,8,1,2                              # reduction candidate for 4,8
B4: 4,8 => CTR
* ..........5724...98..6.947.1.9.23...5.69..123723.1596..6....25....56.....75.....6
B4: 1,2                                  #  7 pairs
C5: 4,8,6                                # reduction candidate for 4,8
C5: 4,8                                  # 19 pairs
B6: 4,8,2                                # reduction candidate for 4,8
B6: 4,8 => CTR
* ..........5724...98..6.947...9..3...5.69..123..3.1.96..6....25....56.....75.....6
B6: 2                                    #  5 pairs
* PAIR B5: 4,8 ROW 5
F5: 4,8,6,7                              # reduction candidate for 4,8
F5: 4,8 => CTR
* ..........5724...98..6.947...9..3...5.697.123..3.1.96..6....25....56.....75.....6
F5: 6,7                                  #  8 pairs
* PAIR B5: 4,8 COL B
B8: 4,8,1,2,3,9                          # reduction candidate for 4,8
B8: 4,8                                  #  8 pairs
B8: 1,2,3,9                              #  7 pairs
* PAIR E5: 7,8 BLK 5
F5: 7,8,4,6                              # reduction candidate for 7,8
F5: 7,8 => CTR
* ..........5724...98..6.947...9..3...5469..123..3.1.96..6....25....56.....75.....6
F5: 4,6                                  #  7 pairs
* PAIR E5: 7,8 COL E
E1: 7,8,3,5                              # reduction candidate for 7,8
E1: 7,8                                  #  8 pairs
E7: 7,8,3,9                              # reduction candidate for 7,8
E7: 7,8                                  #  7 pairs
* PAIR G9: 3,8 BLK 9
G8: 3,8,7                                # reduction candidate for 3,8
G8: 3,8                                  # 11 pairs
H8: 3,8,1,4,9                            # reduction candidate for 3,8
H8: 3,8                                  # 10 pairs
H9: 3,8,1,4,9                            # reduction candidate for 3,8
H9: 3,8                                  # 12 pairs
* PAIR G9: 3,8 ROW 9
D9: 3,8,1,4                              # reduction candidate for 3,8
D9: 3,8                                  #  8 pairs
E9: 3,8,2,9                              # reduction candidate for 3,8
E9: 3,8                                  #  6 pairs
* PAIR G9: 3,8 COL G
G1: 3,8,5,6                              # reduction candidate for 3,8
G1: 3,8                                  #  9 pairs
G2: 3,8,6                                # reduction candidate for 3,8
G2: 3,8                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-082-base-pr-000.dot
* REASONING
* DIS # B4: 4,8 => CTR => B4: 1,2
* DIS # B6: 4,8 => CTR => B6: 2
* DIS # F5: 4,8 => CTR => F5: 6,7
* DIS # F5: 7,8 => CTR => F5: 4,6
* CNT   4 HDP CHAINS /  22 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B5,E3,E4,E5,F6,G9)
* ..........5724...98....947...9..3...5..9..123..3.1.9...6....25....56.....75.....6
* PAIR E3: 3,5 BLK 2
E1: 3,5,7,8                              # reduction candidate for 3,5
E1: 7,8                                  #  8 pairs
E1: 3,5                                  #  7 pairs
* PAIR B5: 4,8 BLK 4
B4: 4,8,1,2                              # reduction candidate for 4,8
B4: 4,8 => CTR
* ..........5724...98..6.947.1.9.23...5.69..123723.1596..6....25....56.....75.....6
C5: 4,8,6                                # reduction candidate for 4,8
C5: 4,8                                  # 19 pairs
B6: 4,8,2                                # reduction candidate for 4,8
B6: 4,8 => CTR
* ..........5724...98..6.947...9..3...5.69..123..3.1.96..6....25....56.....75.....6
* RESTART
* PAIR B5: 4,8 BLK 4
C5: 4,8,6                                # reduction candidate for 4,8
C5: 6 => CTR
* ..........5724...983.65947..19823...586974123.23.159...6....25....56.....75.....6
* PAIR B5: 4,8 COL B
B8: 4,8,9                                # reduction candidate for 4,8
B8: 9 => SOLVED
* 946731582157248639832659471719423865584976123623815947461397258398562714275184396
* DURATION: 0:00:08.585383  START: 00:50:52.297213  END: 00:51:00.882596 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-082-base-pr-001.dot
* REASONING
* DIS # B4: 4,8 => CTR => B4: 1,2
* DIS B4: 1,2 # B6: 4,8 => CTR => B6: 2
* DIS B4: 1,2 + B6: 2 # C5: 6 => CTR => C5: 4,8
* PRF B4: 1,2 + B6: 2 + C5: 4,8 # B8: 9 => SOL
* STA B4: 1,2 + B6: 2 + C5: 4,8 + B8: 9
* CNT   4 HDP CHAINS /   9 HYP OPENED

Header Info

Top 95 Sudokus 082
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 946731582157248639832659471719423865584976123623815947461397258398562714275184396 solved
Solution

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 # E1: 3,5 => UNS
* INC # E1: 7,8 => UNS
* DIS # B4: 4,8 => CTR => B4: 1,2
* INC # B4: 1,2 => UNS
* INC # C5: 4,8 => UNS
* DIS # B6: 4,8 => CTR => B6: 2
* INC # B6: 2 => UNS
* DIS # F5: 4,8 => CTR => F5: 6,7
* INC # F5: 6,7 => UNS
* INC # B8: 4,8 => UNS
* INC # B8: 1,2,3,9 => UNS
* DIS # F5: 7,8 => CTR => F5: 4,6
* INC # F5: 4,6 => UNS
* INC # E1: 7,8 => UNS
* INC # E7: 7,8 => UNS
* INC # G8: 3,8 => UNS
* INC # H8: 3,8 => UNS
* INC # H9: 3,8 => UNS
* INC # D9: 3,8 => UNS
* INC # E9: 3,8 => UNS
* INC # G1: 3,8 => UNS
* INC # G2: 3,8 => UNS
* CNT  22 HDP CHAINS /  22 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # E1: 3,5 => UNS
* INC # E1: 7,8 => UNS
* DIS # B4: 4,8 => CTR => B4: 1,2
* INC B4: 1,2 # C5: 4,8 => UNS
* DIS B4: 1,2 # B6: 4,8 => CTR => B6: 2
* INC B4: 1,2 + B6: 2 # C5: 4,8 => UNS
* DIS B4: 1,2 + B6: 2 # C5: 6 => CTR => C5: 4,8
* INC B4: 1,2 + B6: 2 + C5: 4,8 # B8: 4,8 => UNS
* PRF B4: 1,2 + B6: 2 + C5: 4,8 # B8: 9 => SOL
* STA B4: 1,2 + B6: 2 + C5: 4,8 + B8: 9
* CNT   9 HDP CHAINS /   9 HYP OPENED