Analysis of zz-www.sudokuwiki.org-0110-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=110

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=110

position: 4..3.......8.4.7...3......1.5...1.968...9....96.5...1.7......4...1.8.5.......3..2 initial

Autosolve

position: 47.31....1.8.4.7...3....4.1.5...1.9681..9....96.5...1.7......4...1.8.5.......3..2 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C1: 2,9 => CTR => C1: 5,6
* DIS # B7: 2,9 => CTR => B7: 8
* DIS # F1: 6,9 => CTR => F1: 2,5,8
* DIS # G9: 6,9 => CTR => G9: 1
* DIS # C4: 2,3 => CTR => C4: 4,7
* DIS # C6: 2,3 => CTR => C6: 4,7
* DIS # G4: 2,3 => CTR => G4: 8
* DIS # G4: 2,3 => CTR => G4: 8
* DIS # C5: 4,7 => CTR => C5: 2,3
* DIS # F6: 4,7 => CTR => F6: 2,8
* DIS # C7: 5,6 => CTR => C7: 2,3,9
* DIS # C9: 5,6 => CTR => C9: 9
* DIS # E9: 7 => CTR => E9: 5,6
* CNT  13 HDP CHAINS /  44 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 # C1: 2,9 => CTR => C1: 5,6
* DIS C1: 5,6 # B7: 2,9 => CTR => B7: 8
* DIS C1: 5,6 + B7: 8 # B8: 4 => CTR => B8: 2,9
* PRF C1: 5,6 + B7: 8 + B8: 2,9 # C3: 5,6 => SOL
* STA C1: 5,6 + B7: 8 + B8: 2,9 + C3: 5,6
* CNT   4 HDP CHAINS /  12 HYP OPENED

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

Details

Positions

4..3.......8.4.7...3......1.5...1.968...9....96.5...1.7......4...1.8.5.......3..2 initial
47.31....1.8.4.7...3....4.1.5...1.9681..9....96.5...1.7......4...1.8.5.......3..2 autosolve
476315928198246735235879461357421896812697354964538217783152649621984573549763182 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
B2: 2,9
G1: 6,9
A4: 2,3
G5: 2,3
H5: 5,7
I6: 4,7
A9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D7,D9: 1.. / D7 = 1  =>  8 pairs (_) / D9 = 1  =>  0 pairs (X)
G7,G9: 1.. / G7 = 1  =>  0 pairs (X) / G9 = 1  =>  8 pairs (_)
D7,G7: 1.. / D7 = 1  =>  8 pairs (_) / G7 = 1  =>  0 pairs (X)
D9,G9: 1.. / D9 = 1  =>  0 pairs (X) / G9 = 1  =>  8 pairs (_)
H2,I2: 3.. / H2 = 3  =>  9 pairs (_) / I2 = 3  => 13 pairs (_)
E4,E6: 3.. / E4 = 3  =>  0 pairs (X) / E6 = 3  =>  9 pairs (_)
C7,A8: 3.. / C7 = 3  => 11 pairs (_) / A8 = 3  =>  0 pairs (X)
C5,G5: 3.. / C5 = 3  =>  0 pairs (X) / G5 = 3  =>  8 pairs (_)
C7,I7: 3.. / C7 = 3  => 11 pairs (_) / I7 = 3  =>  0 pairs (X)
A4,A8: 3.. / A4 = 3  => 11 pairs (_) / A8 = 3  =>  0 pairs (X)
H2,H8: 3.. / H2 = 3  =>  9 pairs (_) / H8 = 3  => 13 pairs (_)
I5,I6: 4.. / I5 = 4  =>  9 pairs (_) / I6 = 4  =>  7 pairs (_)
B8,B9: 4.. / B8 = 4  => 12 pairs (_) / B9 = 4  =>  9 pairs (_)
C4,D4: 4.. / C4 = 4  =>  8 pairs (_) / D4 = 4  => 10 pairs (_)
B9,D9: 4.. / B9 = 4  =>  9 pairs (_) / D9 = 4  => 12 pairs (_)
H5,I5: 5.. / H5 = 5  =>  8 pairs (_) / I5 = 5  =>  9 pairs (_)
A3,A9: 5.. / A3 = 5  => 11 pairs (_) / A9 = 5  =>  9 pairs (_)
D5,F5: 6.. / D5 = 6  => 10 pairs (_) / F5 = 6  =>  7 pairs (_)
D4,F6: 8.. / D4 = 8  =>  0 pairs (X) / F6 = 8  =>  8 pairs (_)
G4,G6: 8.. / G4 = 8  =>  8 pairs (_) / G6 = 8  =>  0 pairs (X)
B7,B9: 8.. / B7 = 8  =>  9 pairs (_) / B9 = 8  =>  0 pairs (X)
I7,H9: 8.. / I7 = 8  =>  0 pairs (X) / H9 = 8  =>  9 pairs (_)
D4,G4: 8.. / D4 = 8  =>  0 pairs (X) / G4 = 8  =>  8 pairs (_)
F6,G6: 8.. / F6 = 8  =>  8 pairs (_) / G6 = 8  =>  0 pairs (X)
B7,I7: 8.. / B7 = 8  =>  9 pairs (_) / I7 = 8  =>  0 pairs (X)
B9,H9: 8.. / B9 = 8  =>  0 pairs (X) / H9 = 8  =>  9 pairs (_)
D3,D4: 8.. / D3 = 8  =>  8 pairs (_) / D4 = 8  =>  0 pairs (X)
I1,I7: 8.. / I1 = 8  =>  9 pairs (_) / I7 = 8  =>  0 pairs (X)
* DURATION: 0:00:39.371081  START: 05:28:18.395074  END: 05:28:57.766155 2017-05-01
* CP COUNT: (28)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B2,G1,G5,H5,I6)
* 47.31....1.8.4.7...3....4.1.5...1.9681..9....96.5...1.7......4...1.8.5.......3..2
* PAIR B2: 2,9 BLK 1
C1: 2,9,5,6                              # reduction candidate for 2,9
C1: 2,9 => CTR
* 47231.658198.4.7...3....4.1.5...1.9681..9....96.5...1.7..1...433.1.8.56...9..3182
C1: 5,6                                  #  8 pairs
C3: 2,9,5,6                              # reduction candidate for 2,9
C3: 2,9                                  # 11 pairs
* PAIR B2: 2,9 ROW 2
D2: 2,9,6                                # reduction candidate for 2,9
D2: 2,9                                  # 10 pairs
F2: 2,9,5,6                              # reduction candidate for 2,9
F2: 2,9                                  # 11 pairs
* PAIR B2: 2,9 COL B
B7: 2,9,8                                # reduction candidate for 2,9
B7: 2,9 => CTR
* 47.31..8.198.4.72323.8.94.1354721896812.9.3..9675382147231...48641.8.5..5894.31.2
B7: 8                                    #  9 pairs
B8: 2,9,4                                # reduction candidate for 2,9
B8: 2,9                                  #  9 pairs
* PAIR G1: 6,9 ROW 1
C1: 6,9,2,5                              # reduction candidate for 6,9
C1: 6,9                                  #  9 pairs
F1: 6,9,2,5,8                            # reduction candidate for 6,9
F1: 6,9 => CTR
* 47.3169..198245763236.7.45135..2189681.69.37596.5382147.315.64.6.1.875395.94631.2
F1: 2,5,8                                #  7 pairs
* PAIR G1: 6,9 COL G
G7: 6,9,1                                # reduction candidate for 6,9
G7: 6,9                                  #  8 pairs
G9: 6,9,1                                # reduction candidate for 6,9
G9: 6,9 => CTR
* 47.3196.81286457...398.74.1.5...189681..9....96.5.8.1.78....14..91.8.5...4.173982
G9: 1                                    #  8 pairs
* PAIR A4: 2,3 BLK 4
C4: 2,3,4,7                              # reduction candidate for 2,3
C4: 2,3 => CTR
* 47.31...81.8.4.7...398.74.1.5.47189681..9.3..96.53821.78.1...4..91.845...4.7.3182
C4: 4,7                                  #  8 pairs
C5: 2,3,4,7                              # reduction candidate for 2,3
C5: 2,3                                  # 12 pairs
C6: 2,3,4,7                              # reduction candidate for 2,3
C6: 2,3 => CTR
* 47.318.2.198.4.763236.5.4813548712968176923..9625348177.31...486.1.8.5..589463172
C6: 4,7                                  # 10 pairs
* PAIR A4: 2,3 ROW 4
E4: 2,3,7                                # reduction candidate for 2,3
E4: 2,3                                  # 11 pairs
G4: 2,3,8                                # reduction candidate for 2,3
G4: 2,3 => CTR
* 47.3189.5198.457.323....481.54871.9681..9..5.96.53.81.7231...48641.8.539589463172
G4: 8                                    #  8 pairs
* PAIR A4: 2,3 COL A
A8: 2,3,6                                # reduction candidate for 2,3
A8: 6                                    # 17 pairs
A8: 2,3                                  #  9 pairs
* PAIR G5: 2,3 BLK 6
G4: 2,3,8                                # reduction candidate for 2,3
G4: 2,3 => CTR
* 47.3189.5198.457.323....481.54871.9681..9..5.96.53.81.7231...48641.8.539589463172
G4: 8                                    #  8 pairs
G6: 2,3,8                                # reduction candidate for 2,3
G6: 2,3                                  #  8 pairs
* PAIR G5: 2,3 ROW 5
C5: 2,3,4,7                              # reduction candidate for 2,3
C5: 4,7 => CTR
* 47.318.2.198.4.7..23....481354871296817.9.3549625348177231...48641.82539589463172
C5: 2,3                                  # 12 pairs
* PAIR H5: 5,7 BLK 6
I5: 5,7,4                                # reduction candidate for 5,7
I5: 4                                    #  9 pairs
I5: 5,7                                  #  7 pairs
* PAIR I6: 4,7 BLK 6
I5: 4,7,5                                # reduction candidate for 4,7
I5: 5                                    #  9 pairs
I5: 4,7                                  #  8 pairs
* PAIR I6: 4,7 ROW 6
C6: 4,7,2,3                              # reduction candidate for 4,7
C6: 4,7                                  # 10 pairs
F6: 4,7,2,8                              # reduction candidate for 4,7
F6: 4,7 => CTR
* 47.31.9..198.4.7..23..5.4.1354871296817.9.3549625348177.3125649621489573549763182
F6: 2,8                                  #  8 pairs
* PAIR A9: 5,6 BLK 7
C7: 5,6,2,3,9                            # reduction candidate for 5,6
C7: 5,6 => CTR
* 47.31.9.8198.4.735.3....4.125...1.9681..9..5.96.5...1.78.....43321.8.579.49..3.82
C7: 2,3,9                                #  8 pairs
C9: 5,6,9                                # reduction candidate for 5,6
C9: 5,6 => CTR
* 47.3129.8128.4.7...39867421.5...189681..9....96.5.8.1.78.1596433.128657.....73182
C9: 9                                    # 13 pairs
* PAIR A9: 5,6 ROW 9
E9: 5,6,7                                # reduction candidate for 5,6
E9: 7 => CTR
* 47.3129.8128.4.7...39867421.5...189681..9....96.5.8.1.78.1596433.128657.....73182
E9: 5,6                                  # 16 pairs
* PAIR A9: 5,6 COL A
A3: 5,6,2                                # reduction candidate for 5,6
A3: 2                                    # 17 pairs
A3: 5,6                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0110-base-pr-000.dot
* REASONING
* DIS # C1: 2,9 => CTR => C1: 5,6
* DIS # B7: 2,9 => CTR => B7: 8
* DIS # F1: 6,9 => CTR => F1: 2,5,8
* DIS # G9: 6,9 => CTR => G9: 1
* DIS # C4: 2,3 => CTR => C4: 4,7
* DIS # C6: 2,3 => CTR => C6: 4,7
* DIS # G4: 2,3 => CTR => G4: 8
* DIS # G4: 2,3 => CTR => G4: 8
* DIS # C5: 4,7 => CTR => C5: 2,3
* DIS # F6: 4,7 => CTR => F6: 2,8
* DIS # C7: 5,6 => CTR => C7: 2,3,9
* DIS # C9: 5,6 => CTR => C9: 9
* DIS # E9: 7 => CTR => E9: 5,6
* CNT  13 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B2,G1,G5,H5,I6)
* 47.31....1.8.4.7...3....4.1.5...1.9681..9....96.5...1.7......4...1.8.5.......3..2
* PAIR B2: 2,9 BLK 1
C1: 2,9,5,6                              # reduction candidate for 2,9
C1: 2,9 => CTR
* 47231.658198.4.7...3....4.1.5...1.9681..9....96.5...1.7..1...433.1.8.56...9..3182
C3: 2,9,5,6                              # reduction candidate for 2,9
C3: 2,9                                  # 11 pairs
* RESTART
* PAIR B2: 2,9 BLK 1
C3: 2,9,5,6                              # reduction candidate for 2,9
C3: 5,6                                  # 17 pairs
C3: 2,9                                  # 11 pairs
* PAIR B2: 2,9 ROW 2
D2: 2,9,6                                # reduction candidate for 2,9
D2: 2,9                                  # 11 pairs
F2: 2,9,5,6                              # reduction candidate for 2,9
F2: 2,9                                  # 12 pairs
* PAIR B2: 2,9 COL B
B7: 2,9,8                                # reduction candidate for 2,9
B7: 2,9 => CTR
* 47.31..8.198.4.72323.8.94.1354721896812.9.3..9675382147231...48641.8.5..5894.31.2
B8: 2,9,4                                # reduction candidate for 2,9
B8: 2,9                                  # 10 pairs
* RESTART
* PAIR B2: 2,9 COL B
B8: 2,9,4                                # reduction candidate for 2,9
B8: 4 => CTR
* 47.3129.812894.7...398.74212547318968136942..9675283147821..64334128657..9.473182
* PAIR RESTART
* PAIR B2: 2,9 BLK 1
C3: 2,9,5,6                              # reduction candidate for 2,9
C3: 5,6 => SOLVED
* 476315928198246735235879461357421896812697354964538217783152649621984573549763182
* DURATION: 0:00:11.445944  START: 05:29:32.469681  END: 05:29:43.915625 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0110-base-pr-001.dot
* REASONING
* DIS # C1: 2,9 => CTR => C1: 5,6
* DIS C1: 5,6 # B7: 2,9 => CTR => B7: 8
* DIS C1: 5,6 + B7: 8 # B8: 4 => CTR => B8: 2,9
* PRF C1: 5,6 + B7: 8 + B8: 2,9 # C3: 5,6 => SOL
* STA C1: 5,6 + B7: 8 + B8: 2,9 + C3: 5,6
* CNT   4 HDP CHAINS /  12 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=110

Solution

position: 476315928198246735235879461357421896812697354964538217783152649621984573549763182 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:

* DIS # C1: 2,9 => CTR => C1: 5,6
* INC # C1: 5,6 => UNS
* INC # C3: 2,9 => UNS
* INC # D2: 2,9 => UNS
* INC # F2: 2,9 => UNS
* DIS # B7: 2,9 => CTR => B7: 8
* INC # B7: 8 => UNS
* INC # B8: 2,9 => UNS
* INC # C1: 6,9 => UNS
* DIS # F1: 6,9 => CTR => F1: 2,5,8
* INC # F1: 2,5,8 => UNS
* INC # G7: 6,9 => UNS
* DIS # G9: 6,9 => CTR => G9: 1
* INC # G9: 1 => UNS
* DIS # C4: 2,3 => CTR => C4: 4,7
* INC # C4: 4,7 => UNS
* INC # C5: 2,3 => UNS
* DIS # C6: 2,3 => CTR => C6: 4,7
* INC # C6: 4,7 => UNS
* INC # E4: 2,3 => UNS
* DIS # G4: 2,3 => CTR => G4: 8
* INC # G4: 8 => UNS
* INC # A8: 2,3 => UNS
* INC # A8: 6 => UNS
* DIS # G4: 2,3 => CTR => G4: 8
* INC # G4: 8 => UNS
* INC # G6: 2,3 => UNS
* INC # C5: 2,3 => UNS
* DIS # C5: 4,7 => CTR => C5: 2,3
* INC # I5: 5,7 => UNS
* INC # I5: 4 => UNS
* INC # I5: 4,7 => UNS
* INC # I5: 5 => UNS
* INC # C6: 4,7 => UNS
* DIS # F6: 4,7 => CTR => F6: 2,8
* INC # F6: 2,8 => UNS
* DIS # C7: 5,6 => CTR => C7: 2,3,9
* INC # C7: 2,3,9 => UNS
* DIS # C9: 5,6 => CTR => C9: 9
* INC # C9: 9 => UNS
* INC # E9: 5,6 => UNS
* DIS # E9: 7 => CTR => E9: 5,6
* INC # A3: 5,6 => UNS
* INC # A3: 2 => UNS
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # C1: 2,9 => CTR => C1: 5,6
* INC C1: 5,6 # C3: 2,9 => UNS
* INC C1: 5,6 # C3: 2,9 => UNS
* INC C1: 5,6 # C3: 5,6 => UNS
* INC C1: 5,6 # D2: 2,9 => UNS
* INC C1: 5,6 # F2: 2,9 => UNS
* DIS C1: 5,6 # B7: 2,9 => CTR => B7: 8
* INC C1: 5,6 + B7: 8 # B8: 2,9 => UNS
* INC C1: 5,6 + B7: 8 # B8: 2,9 => UNS
* DIS C1: 5,6 + B7: 8 # B8: 4 => CTR => B8: 2,9
* INC C1: 5,6 + B7: 8 + B8: 2,9 # C3: 2,9 => UNS
* PRF C1: 5,6 + B7: 8 + B8: 2,9 # C3: 5,6 => SOL
* STA C1: 5,6 + B7: 8 + B8: 2,9 + C3: 5,6
* CNT  12 HDP CHAINS /  12 HYP OPENED