Analysis of xx-top95-053-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2....5938..5..46.94..6...8..2.3.....6..8.73.7..2.........4.38..7....6..........5 initial

Autosolve

position: .2....5938..5..46.945.6...8..2.3.....6..8.7327..2.........4.38..7....6..........5 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C1: 7 => CTR => C1: 1,6
* DIS # C2: 1,3 => CTR => C2: 7
* PRF # C1: 6 => SOL
* DIS # H3: 2 => CTR => H3: 1,7
* DIS # C2: 3 => CTR => C2: 1,7
* DIS # I7: 9 => CTR => I7: 1,7
* DIS # H3: 1,2 => CTR => H3: 7
* CNT   7 HDP CHAINS /  29 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: 7 => CTR => C1: 1,6
* PRF C1: 1,6 # D8: 8 => SOL
* STA C1: 1,6 + D8: 8
* CNT   2 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.2....5938..5..46.94..6...8..2.3.....6..8.73.7..2.........4.38..7....6..........5 initial
.2....5938..5..46.945.6...8..2.3.....6..8.7327..2.........4.38..7....6..........5 autosolve
126478593837592461945361278412937856569184732783256914251649387374815629698723145 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
A1: 1,6
B2: 1,3
D1: 4,8
E1: 1,7
F1: 4,8
E2: 2,9
F2: 2,9
I2: 1,7
G3: 1,2

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,F2: 2.. / E2 = 2  =>  7 pairs (_) / F2 = 2  =>  8 pairs (_)
G3,H3: 2.. / G3 = 2  => 10 pairs (_) / H3 = 2  =>  0 pairs (X)
A7,F7: 2.. / A7 = 2  =>  9 pairs (_) / F7 = 2  => 10 pairs (_)
G3,G9: 2.. / G3 = 2  => 10 pairs (_) / G9 = 2  =>  0 pairs (X)
B2,C2: 3.. / B2 = 3  => 10 pairs (_) / C2 = 3  =>  0 pairs (X)
D3,F3: 3.. / D3 = 3  => 10 pairs (_) / F3 = 3  => 10 pairs (_)
B6,C6: 3.. / B6 = 3  =>  0 pairs (X) / C6 = 3  => 10 pairs (_)
A8,A9: 3.. / A8 = 3  =>  9 pairs (_) / A9 = 3  =>  9 pairs (_)
B2,B6: 3.. / B2 = 3  => 10 pairs (_) / B6 = 3  =>  0 pairs (X)
C2,C6: 3.. / C2 = 3  =>  0 pairs (X) / C6 = 3  => 10 pairs (_)
D1,F1: 4.. / D1 = 4  =>  8 pairs (_) / F1 = 4  =>  7 pairs (_)
H4,H6: 5.. / H4 = 5  => 11 pairs (_) / H6 = 5  => 11 pairs (_)
A5,F5: 5.. / A5 = 5  => 10 pairs (_) / F5 = 5  => 11 pairs (_)
E6,E8: 5.. / E6 = 5  => 11 pairs (_) / E8 = 5  => 10 pairs (_)
A1,C1: 6.. / A1 = 6  =>  9 pairs (_) / C1 = 6  =>  0 pairs (*)
I4,I6: 6.. / I4 = 6  =>  9 pairs (_) / I6 = 6  => 11 pairs (_)
F6,I6: 6.. / F6 = 6  =>  9 pairs (_) / I6 = 6  => 11 pairs (_)
C1,C2: 7.. / C1 = 7  =>  0 pairs (X) / C2 = 7  => 21 pairs (_)
I2,H3: 7.. / I2 = 7  =>  0 pairs (X) / H3 = 7  => 21 pairs (_)
D4,F4: 7.. / D4 = 7  => 10 pairs (_) / F4 = 7  => 10 pairs (_)
I7,H9: 7.. / I7 = 7  => 21 pairs (_) / H9 = 7  =>  0 pairs (X)
C1,E1: 7.. / C1 = 7  =>  0 pairs (X) / E1 = 7  => 21 pairs (_)
C2,I2: 7.. / C2 = 7  => 21 pairs (_) / I2 = 7  =>  0 pairs (X)
E1,E9: 7.. / E1 = 7  => 21 pairs (_) / E9 = 7  =>  0 pairs (X)
H3,H9: 7.. / H3 = 7  => 21 pairs (_) / H9 = 7  =>  0 pairs (X)
I2,I7: 7.. / I2 = 7  =>  0 pairs (X) / I7 = 7  => 21 pairs (_)
D1,F1: 8.. / D1 = 8  =>  7 pairs (_) / F1 = 8  =>  8 pairs (_)
G4,G6: 8.. / G4 = 8  => 12 pairs (_) / G6 = 8  => 11 pairs (_)
B4,G4: 8.. / B4 = 8  => 11 pairs (_) / G4 = 8  => 12 pairs (_)
E2,F2: 9.. / E2 = 9  =>  8 pairs (_) / F2 = 9  =>  7 pairs (_)
* DURATION: 0:00:38.952729  START: 23:57:40.444244  END: 23:58:19.396973 2017-05-03
* CP COUNT: (30)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B2,D1,E1,E2,F1,F2,G3,I2)
* .2....5938..5..46.945.6...8..2.3.....6..8.7327..2.........4.38..7....6..........5
* PAIR A1: 1,6 BLK 1
C1: 1,6,7                                # reduction candidate for 1,6
C1: 7 => CTR
* 627.1.5938..5..467945.6...8..2.3.....6..8.7327..2.........4.38..7....6......7...5
C1: 1,6                                  # 21 pairs
* PAIR A1: 1,6 COL A
A7: 1,6,2,5                              # reduction candidate for 1,6
A7: 1,6                                  # 13 pairs
A9: 1,6,2,3,4                            # reduction candidate for 1,6
A9: 1,6                                  # 13 pairs
* PAIR B2: 1,3 BLK 1
C2: 1,3,7                                # reduction candidate for 1,3
C2: 1,3 => CTR
* .27.1.5938..5..467945.6...8..2.3.....6..8.7327..2.........4.38..7....6......7...5
C2: 7                                    # 21 pairs
* PAIR B2: 1,3 COL B
B6: 1,3,5,8,9                            # reduction candidate for 1,3
B6: 1,3                                  # 12 pairs
B6: 5,8,9                                # 10 pairs
* PAIR E1: 1,7 BLK 2
D3: 1,7,3                                # reduction candidate for 1,7
D3: 1,7                                  # 10 pairs
F3: 1,7,3                                # reduction candidate for 1,7
F3: 1,7                                  # 10 pairs
* PAIR E1: 1,7 ROW 1
C1: 1,7,6                                # reduction candidate for 1,7
C1: 6 => SOLVED
* 126478593837592461945361278412937856569184732783256914251649387374815629698723145
C1: 1,7                                  #  9 pairs
* PAIR E1: 1,7 COL E
E9: 1,7,2,9                              # reduction candidate for 1,7
E9: 2,9                                  # 21 pairs
E9: 1,7                                  # 11 pairs
* PAIR E2: 2,9 COL E
E8: 2,9,1,5                              # reduction candidate for 2,9
E8: 2,9                                  # 13 pairs
E9: 2,9,1,7                              # reduction candidate for 2,9
E9: 2,9                                  # 21 pairs
* PAIR F2: 2,9 COL F
F7: 2,9,1,5,6,7                          # reduction candidate for 2,9
F7: 2,9                                  # 10 pairs
F8: 2,9,1,3,5,8                          # reduction candidate for 2,9
F8: 2,9                                  # 10 pairs
F9: 2,9,1,3,6,7,8                        # reduction candidate for 2,9
F9: 2,9                                  # 10 pairs
* PAIR I2: 1,7 BLK 3
H3: 1,7,2                                # reduction candidate for 1,7
H3: 2 => CTR
* .2....5938..5..467945.6.128..2.3.....6..8.7327..2.........4.38..7....6........275
H3: 1,7                                  # 10 pairs
* PAIR I2: 1,7 ROW 2
C2: 1,7,3                                # reduction candidate for 1,7
C2: 3 => CTR
* .27.1.5938135..467945.6...8..2.3.....6..8.73273.2.........4.38..7....6......7...5
C2: 1,7                                  # 10 pairs
* PAIR I2: 1,7 COL I
I7: 1,7,9                                # reduction candidate for 1,7
I7: 9 => CTR
* .27.1.5938..5..467945.6...8..2.3.....6..8.7327..2.........4.389.7....6.........75
I7: 1,7                                  # 11 pairs
* PAIR G3: 1,2 BLK 3
H3: 1,2,7                                # reduction candidate for 1,2
H3: 1,2 => CTR
* .27.1.5938..5..467945.6...8..2.3.....6..8.7327..2.........4.38..7....6.........75
H3: 7                                    # 21 pairs
* PAIR G3: 1,2 COL G
G9: 1,2,9                                # reduction candidate for 1,2
G9: 9                                    # 18 pairs
G9: 1,2                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-053-base-pr-000.dot
* REASONING
* DIS # C1: 7 => CTR => C1: 1,6
* DIS # C2: 1,3 => CTR => C2: 7
* PRF # C1: 6 => SOL
* DIS # H3: 2 => CTR => H3: 1,7
* DIS # C2: 3 => CTR => C2: 1,7
* DIS # I7: 9 => CTR => I7: 1,7
* DIS # H3: 1,2 => CTR => H3: 7
* CNT   7 HDP CHAINS /  29 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B2,D1,E1,E2,F1,F2,G3,I2)
* .2....5938..5..46.945.6...8..2.3.....6..8.7327..2.........4.38..7....6..........5
* PAIR A1: 1,6 BLK 1
C1: 1,6,7                                # reduction candidate for 1,6
C1: 7 => CTR
* 627.1.5938..5..467945.6...8..2.3.....6..8.7327..2.........4.38..7....6......7...5

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A1,A5,A9,B4,B7,C1,C7,D1,D3,D4,D5,D7,D9,E6,E8,F1,F3,F4,F9,H4,H6)
* .2..7.593837592461945.6.2784.2.3.8.6.69.8.7327832.69.42...4.387.74...629.98.2.145
* PAIR D3: 1,3 COL D
D8: 1,3,8                                # reduction candidate for 1,3
D8: 8 => SOLVED
* 126478593837592461945361278412937856569184732783256914251649387374815629698723145
* DURATION: 0:00:06.488794  START: 23:58:41.983021  END: 23:58:48.471815 2017-05-03
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-053-base-pr-001.dot
* REASONING
* DIS # C1: 7 => CTR => C1: 1,6
* PRF C1: 1,6 # D8: 8 => SOL
* STA C1: 1,6 + D8: 8
* CNT   2 HDP CHAINS /   4 HYP OPENED

Header Info

Top 95 Sudokus 053
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 126478593837592461945361278412937856569184732783256914251649387374815629698723145 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 # C1: 1,6 => UNS
* DIS # C1: 7 => CTR => C1: 1,6
* INC # A7: 1,6 => UNS
* INC # A9: 1,6 => UNS
* DIS # C2: 1,3 => CTR => C2: 7
* INC # C2: 7 => UNS
* INC # B6: 1,3 => UNS
* INC # B6: 5,8,9 => UNS
* INC # D3: 1,7 => UNS
* INC # F3: 1,7 => UNS
* INC # C1: 1,7 => UNS
* PRF # C1: 6 => SOL
* INC # E9: 1,7 => UNS
* INC # E9: 2,9 => UNS
* INC # E8: 2,9 => UNS
* INC # E9: 2,9 => UNS
* INC # F7: 2,9 => UNS
* INC # F8: 2,9 => UNS
* INC # F9: 2,9 => UNS
* INC # H3: 1,7 => UNS
* DIS # H3: 2 => CTR => H3: 1,7
* INC # C2: 1,7 => UNS
* DIS # C2: 3 => CTR => C2: 1,7
* INC # I7: 1,7 => UNS
* DIS # I7: 9 => CTR => I7: 1,7
* DIS # H3: 1,2 => CTR => H3: 7
* INC # H3: 7 => UNS
* INC # G9: 1,2 => UNS
* INC # G9: 9 => UNS
* CNT  29 HDP CHAINS /  29 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C1: 1,6 => UNS
* DIS # C1: 7 => CTR => C1: 1,6
* INC C1: 1,6 # D8: 1,3 => UNS
* PRF C1: 1,6 # D8: 8 => SOL
* STA C1: 1,6 + D8: 8
* CNT   4 HDP CHAINS /   4 HYP OPENED