Analysis of zz-www.sudokuwiki.org-0013-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=13

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=13

position: 9...4......61..2...2.9.7.311.3...58....8.1....87...1.271.6.8.2...8..43......1...8 initial

Autosolve

position: 9.1.4.8....61..2...2.9.7.311.3...58....8.1..3.87...1.271.638.2...8..431.....1...8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B2: 4,5 => CTR => B2: 3,7
* PRF # C5: 4,5 => SOL
* DIS # C9: 4,5 => CTR => C9: 2,9
* DIS # E3: 6 => CTR => E3: 5,8
* DIS # D1: 3,5 => CTR => D1: 2
* DIS # F1: 3,5 => CTR => F1: 2,6
* DIS # B2: 3,5 => CTR => B2: 4,7
* DIS # F6: 6,9 => CTR => F6: 3,5
* DIS # I7: 4,9 => CTR => I7: 5
* DIS # G9: 4,9 => CTR => G9: 6,7
* DIS # H9: 4,9 => CTR => H9: 5,6,7
* DIS # C7: 5 => CTR => C7: 4,9
* CNT  12 HDP CHAINS /  34 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 # B2: 4,5 => CTR => B2: 3,7
* PRF B2: 3,7 # C5: 4,5 => SOL
* STA B2: 3,7 + C5: 4,5
* CNT   2 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

9...4......61..2...2.9.7.311.3...58....8.1....87...1.271.6.8.2...8..43......1...8 initial
9.1.4.8....61..2...2.9.7.311.3...58....8.1..3.87...1.271.638.2...8..431.....1...8 autosolve
931246857876153294425987631193472586254861973687395142719638425568724319342519768 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (5)
C3: 4,5
E2: 5,8
F2: 3,5
G3: 4,6
G7: 4,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D1,F1: 2.. / D1 = 2  => 10 pairs (_) / F1 = 2  =>  0 pairs (X)
A5,C5: 2.. / A5 = 2  =>  8 pairs (_) / C5 = 2  =>  6 pairs (_)
C5,C9: 2.. / C5 = 2  =>  6 pairs (_) / C9 = 2  =>  8 pairs (_)
E4,E8: 2.. / E4 = 2  =>  7 pairs (_) / E8 = 2  => 12 pairs (_)
D6,F6: 3.. / D6 = 3  =>  7 pairs (_) / F6 = 3  =>  0 pairs (X)
A9,B9: 3.. / A9 = 3  =>  7 pairs (_) / B9 = 3  =>  0 pairs (X)
A2,A9: 3.. / A2 = 3  =>  0 pairs (X) / A9 = 3  =>  7 pairs (_)
D1,D6: 3.. / D1 = 3  =>  0 pairs (X) / D6 = 3  =>  7 pairs (_)
D4,D6: 4.. / D4 = 4  =>  7 pairs (_) / D6 = 4  =>  0 pairs (X)
C7,I7: 5.. / C7 = 5  =>  0 pairs (X) / I7 = 5  =>  7 pairs (_)
F1,E3: 6.. / F1 = 6  => 17 pairs (_) / E3 = 6  =>  0 pairs (X)
E3,G3: 6.. / E3 = 6  =>  0 pairs (X) / G3 = 6  => 17 pairs (_)
B1,B2: 7.. / B1 = 7  =>  0 pairs (X) / B2 = 7  =>  6 pairs (_)
G5,G9: 7.. / G5 = 7  => 20 pairs (_) / G9 = 7  =>  6 pairs (_)
A2,A3: 8.. / A2 = 8  => 15 pairs (_) / A3 = 8  =>  5 pairs (_)
E2,E3: 8.. / E2 = 8  =>  5 pairs (_) / E3 = 8  => 15 pairs (_)
A2,E2: 8.. / A2 = 8  => 15 pairs (_) / E2 = 8  =>  5 pairs (_)
A3,E3: 8.. / A3 = 8  =>  5 pairs (_) / E3 = 8  => 15 pairs (_)
H2,I2: 9.. / H2 = 9  =>  7 pairs (_) / I2 = 9  =>  6 pairs (_)
E8,F9: 9.. / E8 = 9  =>  0 pairs (X) / F9 = 9  =>  6 pairs (_)
* DURATION: 0:00:27.854682  START: 03:37:07.506670  END: 03:37:35.361352 2017-05-01
* CP COUNT: (20)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C3,E2,F2,G3,G7)
* 9.1.4.8....61..2...2.9.7.311.3...58....8.1..3.87...1.271.638.2...8..431.....1...8
* PAIR C3: 4,5 BLK 1
A2: 4,5,3,8                              # reduction candidate for 4,5
A2: 4,5                                  #  8 pairs
B2: 4,5,3,7                              # reduction candidate for 4,5
B2: 4,5 => CTR
* 9713428563461852798259674311.32765844.28.17.3.874.31.2714638925..8524317.3.71.648
B2: 3,7                                  #  6 pairs
A3: 4,5,8                                # reduction candidate for 4,5
A3: 4,5                                  # 15 pairs
* PAIR C3: 4,5 COL C
C5: 4,5,2,9                              # reduction candidate for 4,5
C5: 4,5 => SOLVED
* 931246857876153294425987631193472586254861973687395142719638425568724319342519768
C5: 2,9                                  #  6 pairs
C7: 4,5,9                                # reduction candidate for 4,5
C7: 4,5                                  #  8 pairs
C9: 4,5,2,9                              # reduction candidate for 4,5
C9: 4,5 => CTR
* 931246857.761.32...2.9.76311.34..58...28.1..3.873..1.2719638425..8..431.3...12..8
C9: 2,9                                  #  6 pairs
* PAIR E2: 5,8 BLK 2
E3: 5,8,6                                # reduction candidate for 5,8
E3: 6 => CTR
* 971342856..6185279825967431193276584..28.1..3.874.31.2714638925..8..4317...719648
E3: 5,8                                  # 17 pairs
* PAIR E2: 5,8 ROW 2
A2: 5,8,3,4                              # reduction candidate for 5,8
A2: 5,8                                  # 17 pairs
A2: 3,4                                  #  6 pairs
* PAIR F2: 3,5 BLK 2
D1: 3,5,2                                # reduction candidate for 3,5
D1: 3,5 => CTR
* 971342856..6185279825967431193276584..28.1..3.874.31.2714638925..8..4317...719648
D1: 2                                    # 10 pairs
F1: 3,5,2,6                              # reduction candidate for 3,5
F1: 3,5 => CTR
* 9.124.8....618.2..8259674311.34..58....8.1..3.873..1.271463892...8..431.....1...8
F1: 2,6                                  #  6 pairs
* PAIR F2: 3,5 ROW 2
A2: 3,5,4,8                              # reduction candidate for 3,5
A2: 3,5                                  #  9 pairs
B2: 3,5,4,7                              # reduction candidate for 3,5
B2: 3,5 => CTR
* 9713428564361852798259674311.3276584.4.8.17.3.874.31.2714638925.685.43173..71.648
B2: 4,7                                  #  6 pairs
* PAIR F2: 3,5 COL F
F6: 3,5,6,9                              # reduction candidate for 3,5
F6: 6,9 => CTR
* 9.1.4.8....618.2..8259674311.34..58....8.1..3.873..1.271.63892...8..431.....1...8
F6: 3,5                                  #  8 pairs
* PAIR G3: 4,6 COL G
G5: 4,6,7,9                              # reduction candidate for 4,6
G5: 4,6                                  # 14 pairs
G9: 4,6,7,9                              # reduction candidate for 4,6
G9: 4,6                                  # 20 pairs
* PAIR G7: 4,9 BLK 9
I7: 4,9,5                                # reduction candidate for 4,9
I7: 4,9 => CTR
* 9312468...761.32...249.76311.34..586.5.8.1..3.873..1.2715638.2..68..4315349512768
I7: 5                                    #  7 pairs
G9: 4,9,6,7                              # reduction candidate for 4,9
G9: 4,9 => CTR
* 9312468...761.32.4.2.9.76311.347258.24.8.17.3.873.5142714638925.98.2431.352719468
G9: 6,7                                  #  6 pairs
H9: 4,9,5,6,7                            # reduction candidate for 4,9
H9: 4,9 => CTR
* 9.1.4.857.761..294425987631143..6589269851473.87.9.162714638925.98..431...2.19748
H9: 5,6,7                                #  5 pairs
* PAIR G7: 4,9 ROW 7
C7: 4,9,5                                # reduction candidate for 4,9
C7: 5 => CTR
* 9312468...761.32...249.76311.34..586.5.8.1..3.873..1.2715638.2..68..4315349512768
C7: 4,9                                  #  7 pairs
* PAIR G7: 4,9 COL G
G5: 4,9,6,7                              # reduction candidate for 4,9
G5: 4,9                                  # 16 pairs
G5: 6,7                                  #  7 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0013-base-pr-000.dot
* REASONING
* DIS # B2: 4,5 => CTR => B2: 3,7
* PRF # C5: 4,5 => SOL
* DIS # C9: 4,5 => CTR => C9: 2,9
* DIS # E3: 6 => CTR => E3: 5,8
* DIS # D1: 3,5 => CTR => D1: 2
* DIS # F1: 3,5 => CTR => F1: 2,6
* DIS # B2: 3,5 => CTR => B2: 4,7
* DIS # F6: 6,9 => CTR => F6: 3,5
* DIS # I7: 4,9 => CTR => I7: 5
* DIS # G9: 4,9 => CTR => G9: 6,7
* DIS # H9: 4,9 => CTR => H9: 5,6,7
* DIS # C7: 5 => CTR => C7: 4,9
* CNT  12 HDP CHAINS /  34 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C3,E2,F2,G3,G7)
* 9.1.4.8....61..2...2.9.7.311.3...58....8.1..3.87...1.271.638.2...8..431.....1...8
* PAIR C3: 4,5 BLK 1
A2: 4,5,3,8                              # reduction candidate for 4,5
A2: 4,5                                  #  8 pairs
B2: 4,5,3,7                              # reduction candidate for 4,5
B2: 4,5 => CTR
* 9713428563461852798259674311.32765844.28.17.3.874.31.2714638925..8524317.3.71.648
A3: 4,5,8                                # reduction candidate for 4,5
A3: 4,5                                  # 15 pairs
* PAIR C3: 4,5 COL C
C5: 4,5,2,9                              # reduction candidate for 4,5
C5: 4,5 => SOLVED
* 931246857876153294425987631193472586254861973687395142719638425568724319342519768
* DURATION: 0:00:05.198945  START: 03:38:02.440483  END: 03:38:07.639428 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0013-base-pr-001.dot
* REASONING
* DIS # B2: 4,5 => CTR => B2: 3,7
* PRF B2: 3,7 # C5: 4,5 => SOL
* STA B2: 3,7 + C5: 4,5
* CNT   2 HDP CHAINS /   4 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=13

Solution

position: 931246857876153294425987631193472586254861973687395142719638425568724319342519768 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 # A2: 4,5 => UNS
* DIS # B2: 4,5 => CTR => B2: 3,7
* INC # B2: 3,7 => UNS
* INC # A3: 4,5 => UNS
* PRF # C5: 4,5 => SOL
* INC # C5: 2,9 => UNS
* INC # C7: 4,5 => UNS
* DIS # C9: 4,5 => CTR => C9: 2,9
* INC # C9: 2,9 => UNS
* INC # E3: 5,8 => UNS
* DIS # E3: 6 => CTR => E3: 5,8
* INC # A2: 5,8 => UNS
* INC # A2: 3,4 => UNS
* DIS # D1: 3,5 => CTR => D1: 2
* INC # D1: 2 => UNS
* DIS # F1: 3,5 => CTR => F1: 2,6
* INC # F1: 2,6 => UNS
* INC # A2: 3,5 => UNS
* DIS # B2: 3,5 => CTR => B2: 4,7
* INC # B2: 4,7 => UNS
* INC # F6: 3,5 => UNS
* DIS # F6: 6,9 => CTR => F6: 3,5
* INC # G5: 4,6 => UNS
* INC # G9: 4,6 => UNS
* DIS # I7: 4,9 => CTR => I7: 5
* INC # I7: 5 => UNS
* DIS # G9: 4,9 => CTR => G9: 6,7
* INC # G9: 6,7 => UNS
* DIS # H9: 4,9 => CTR => H9: 5,6,7
* INC # H9: 5,6,7 => UNS
* INC # C7: 4,9 => UNS
* DIS # C7: 5 => CTR => C7: 4,9
* INC # G5: 4,9 => UNS
* INC # G5: 6,7 => UNS
* CNT  34 HDP CHAINS /  34 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A2: 4,5 => UNS
* DIS # B2: 4,5 => CTR => B2: 3,7
* INC B2: 3,7 # A3: 4,5 => UNS
* PRF B2: 3,7 # C5: 4,5 => SOL
* STA B2: 3,7 + C5: 4,5
* CNT   4 HDP CHAINS /   4 HYP OPENED