Analysis of zz-www.sudokuwiki.org-0062-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=62

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=62

position: .3...8....6.....272.4...9.......3.4...6.9.1...5.71......2...3.554.....1....8...9. initial

Autosolve

position: .3...8....6.....272.4...9......83.4...6.9.1...5.71......2...3.554.....1....8...9. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # H3: 5,6 => CTR => H3: 3,8
* DIS # A7: 1,7 => CTR => A7: 6,8,9
* DIS # B7: 1,7 => CTR => B7: 8,9
* PRF # A9: 1,7 => SOL
* CNT   4 HDP CHAINS /  16 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 # H3: 5,6 => CTR => H3: 3,8
* DIS H3: 3,8 # A7: 1,7 => CTR => A7: 6,8,9
* DIS H3: 3,8 + A7: 6,8,9 # B7: 1,7 => CTR => B7: 8,9
* PRF H3: 3,8 + A7: 6,8,9 + B7: 8,9 # A9: 1,7 => SOL
* STA H3: 3,8 + A7: 6,8,9 + B7: 8,9 + A9: 1,7
* CNT   4 HDP CHAINS /   7 HYP OPENED

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

Details

Positions

.3...8....6.....272.4...9.......3.4...6.9.1...5.71......2...3.554.....1....8...9. initial
.3...8....6.....272.4...9......83.4...6.9.1...5.71......2...3.554.....1....8...9. autosolve
937248651865931427214567938721683549386495172459712863692174385548329716173856294 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
H1: 5,6
G4: 5,7
H5: 5,7
B9: 1,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I1,I3: 1.. / I1 = 1  =>  5 pairs (_) / I3 = 1  =>  0 pairs (X)
D1,E1: 2.. / D1 = 2  =>  7 pairs (_) / E1 = 2  =>  5 pairs (_)
B4,B5: 2.. / B4 = 2  =>  7 pairs (_) / B5 = 2  => 13 pairs (_)
D2,E2: 3.. / D2 = 3  =>  5 pairs (_) / E2 = 3  =>  4 pairs (_)
H3,I3: 3.. / H3 = 3  =>  6 pairs (_) / I3 = 3  =>  8 pairs (_)
A5,I5: 3.. / A5 = 3  =>  7 pairs (_) / I5 = 3  =>  7 pairs (_)
D2,D8: 3.. / D2 = 3  =>  5 pairs (_) / D8 = 3  =>  4 pairs (_)
H3,H6: 3.. / H3 = 3  =>  6 pairs (_) / H6 = 3  =>  8 pairs (_)
A5,A6: 4.. / A5 = 4  =>  0 pairs (X) / A6 = 4  =>  5 pairs (_)
G9,I9: 4.. / G9 = 4  =>  0 pairs (X) / I9 = 4  =>  5 pairs (_)
A6,F6: 4.. / A6 = 4  =>  5 pairs (_) / F6 = 4  =>  0 pairs (X)
I1,I9: 4.. / I1 = 4  =>  0 pairs (X) / I9 = 4  =>  5 pairs (_)
C1,C2: 5.. / C1 = 5  => 10 pairs (_) / C2 = 5  =>  6 pairs (_)
G4,H5: 5.. / G4 = 5  =>  7 pairs (_) / H5 = 5  =>  0 pairs (X)
E9,F9: 5.. / E9 = 5  =>  6 pairs (_) / F9 = 5  =>  6 pairs (_)
D4,G4: 5.. / D4 = 5  =>  0 pairs (X) / G4 = 5  =>  7 pairs (_)
D4,F6: 6.. / D4 = 6  =>  9 pairs (_) / F6 = 6  => 11 pairs (_)
A7,A9: 6.. / A7 = 6  =>  8 pairs (_) / A9 = 6  =>  8 pairs (_)
D4,I4: 6.. / D4 = 6  =>  9 pairs (_) / I4 = 6  => 11 pairs (_)
G4,H5: 7.. / G4 = 7  =>  0 pairs (X) / H5 = 7  =>  7 pairs (_)
H5,H7: 7.. / H5 = 7  =>  7 pairs (_) / H7 = 7  =>  0 pairs (X)
I4,I6: 9.. / I4 = 9  =>  0 pairs (*) / I6 = 9  =>  0 pairs (X)
B4,B7: 9.. / B4 = 9  => 15 pairs (_) / B7 = 9  =>  4 pairs (_)
* DURATION: 0:00:25.874391  START: 04:32:24.364989  END: 04:32:50.239380 2017-05-01
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,G4,H1,H5)
* .3...8....6.....272.4...9......83.4...6.9.1...5.71......2...3.554.....1....8...9.
* PAIR H1: 5,6 BLK 3
G1: 5,6,4                                # reduction candidate for 5,6
G1: 5,6                                  #  9 pairs
H3: 5,6,3,8                              # reduction candidate for 5,6
H3: 5,6 => CTR
* .3...8..186.....272.4...9.3....83.4.386.9.172459712836..2...385548....1...38...9.
H3: 3,8                                  #  6 pairs
* PAIR H1: 5,6 ROW 1
D1: 5,6,1,2,4,9                          # reduction candidate for 5,6
D1: 5,6                                  # 23 pairs
E1: 5,6,2,4,7                            # reduction candidate for 5,6
E1: 5,6                                  # 24 pairs
* PAIR B9: 1,7 BLK 7
A7: 1,7,6,8,9                            # reduction candidate for 1,7
A7: 1,7 => CTR
* 937..8651865139427214...9..7.1.8354...6.9.17..5.71.8..1.2...3.5548....1.6738.1294
A7: 6,8,9                                #  4 pairs
B7: 1,7,8,9                              # reduction candidate for 1,7
B7: 1,7 => CTR
* .3...8....6....827284...9...9..83.4..26.9.1...5871...98.2...3.5549....186.38...9.
B7: 8,9                                  #  5 pairs
A9: 1,7,3,6                              # reduction candidate for 1,7
A9: 1,7 => SOLVED
* 937248651865931427214567938721683549386495172459712863692174385548329716173856294
A9: 3,6                                  #  5 pairs
C9: 1,7,3                                # reduction candidate for 1,7
C9: 1,7                                  #  7 pairs
* PAIR B9: 1,7 ROW 9
F9: 1,7,2,5,6                            # reduction candidate for 1,7
F9: 1,7                                  # 13 pairs
F9: 2,5,6                                #  4 pairs
* PAIR B9: 1,7 COL B
B3: 1,7,8                                # reduction candidate for 1,7
B3: 1,7                                  # 13 pairs
B4: 1,7,2,9                              # reduction candidate for 1,7
B4: 1,7                                  # 20 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0062-base-pr-000.dot
* REASONING
* DIS # H3: 5,6 => CTR => H3: 3,8
* DIS # A7: 1,7 => CTR => A7: 6,8,9
* DIS # B7: 1,7 => CTR => B7: 8,9
* PRF # A9: 1,7 => SOL
* CNT   4 HDP CHAINS /  16 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,G4,H1,H5)
* .3...8....6.....272.4...9......83.4...6.9.1...5.71......2...3.554.....1....8...9.
* PAIR H1: 5,6 BLK 3
G1: 5,6,4                                # reduction candidate for 5,6
G1: 5,6                                  #  9 pairs
H3: 5,6,3,8                              # reduction candidate for 5,6
H3: 5,6 => CTR
* .3...8..186.....272.4...9.3....83.4.386.9.172459712836..2...385548....1...38...9.
* RESTART
* PAIR H1: 5,6 BLK 3
G1: 5,6,4                                # reduction candidate for 5,6
G1: 5,6                                  #  9 pairs
G1: 4                                    #  8 pairs
* PAIR B9: 1,7 BLK 7
A7: 1,7,6,8,9                            # reduction candidate for 1,7
A7: 1,7 => CTR
* 937..8651865139427214...9..7.1.8354...6.9.17..5.71.8..1.2...3.5548....1.6738.1294
B7: 1,7,8,9                              # reduction candidate for 1,7
B7: 1,7 => CTR
* .3...8....6....827284...93..9..83.4.826.9.17345371..89..2...36554.....18...8...9.
A9: 1,7,3,6                              # reduction candidate for 1,7
A9: 1,7 => SOLVED
* 937248651865931427214567938721683549386495172459712863692174385548329716173856294
* DURATION: 0:00:07.360732  START: 04:33:02.162046  END: 04:33:09.522778 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0062-base-pr-001.dot
* REASONING
* DIS # H3: 5,6 => CTR => H3: 3,8
* DIS H3: 3,8 # A7: 1,7 => CTR => A7: 6,8,9
* DIS H3: 3,8 + A7: 6,8,9 # B7: 1,7 => CTR => B7: 8,9
* PRF H3: 3,8 + A7: 6,8,9 + B7: 8,9 # A9: 1,7 => SOL
* STA H3: 3,8 + A7: 6,8,9 + B7: 8,9 + A9: 1,7
* CNT   4 HDP CHAINS /   7 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=62

Solution

position: 937248651865931427214567938721683549386495172459712863692174385548329716173856294 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 # G1: 5,6 => UNS
* DIS # H3: 5,6 => CTR => H3: 3,8
* INC # H3: 3,8 => UNS
* INC # D1: 5,6 => UNS
* INC # E1: 5,6 => UNS
* DIS # A7: 1,7 => CTR => A7: 6,8,9
* INC # A7: 6,8,9 => UNS
* DIS # B7: 1,7 => CTR => B7: 8,9
* INC # B7: 8,9 => UNS
* PRF # A9: 1,7 => SOL
* INC # A9: 3,6 => UNS
* INC # C9: 1,7 => UNS
* INC # F9: 1,7 => UNS
* INC # F9: 2,5,6 => UNS
* INC # B3: 1,7 => UNS
* INC # B4: 1,7 => UNS
* CNT  16 HDP CHAINS /  16 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # G1: 5,6 => UNS
* DIS # H3: 5,6 => CTR => H3: 3,8
* INC H3: 3,8 # G1: 5,6 => UNS
* INC H3: 3,8 # G1: 4 => UNS
* DIS H3: 3,8 # A7: 1,7 => CTR => A7: 6,8,9
* DIS H3: 3,8 + A7: 6,8,9 # B7: 1,7 => CTR => B7: 8,9
* PRF H3: 3,8 + A7: 6,8,9 + B7: 8,9 # A9: 1,7 => SOL
* STA H3: 3,8 + A7: 6,8,9 + B7: 8,9 + A9: 1,7
* CNT   7 HDP CHAINS /   7 HYP OPENED