Analysis of xx-top95-047-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..9.....3.....9...7.....5.6..65..4.....3......28......3..75.6..6...........12.3.8 initial

Autosolve

position: ..9.75..3....39...7432815969365124871..34896242896713538.7546.96..893.5.59.1263.8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B2: 1,6 => SOL
* DIS # B2: 5 => CTR => B2: 1,6
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* DIS # B2: 1,5 => CTR => B2: 6
* PRF # B2: 6 => SOL
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,2 => SOL
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,7 => SOL
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,2 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* PRF # C8: 1,4 => SOL
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,4 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* CNT  19 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:

* PRF # B2: 1,6 => SOL
* STA B2: 1,6
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

..9.....3.....9...7.....5.6..65..4.....3......28......3..75.6..6...........12.3.8 initial
..9.75..3....39...7432815969365124871..34896242896713538.7546.96..893.5.59.1263.8 autosolve
219675843865439721743281596936512487157348962428967135382754619671893254594126378 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
A1: 2,8
B1: 1,6
A2: 2,8
C2: 1,5
D1: 4,6
D2: 4,6
G1: 2,8
H1: 1,4
H2: 2,7
I2: 1,4
B5: 5,7
C5: 5,7
C7: 1,2
B8: 1,7
C9: 4,7
H7: 1,2
G8: 2,7
I8: 1,4
H9: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H1,I2: 1.. / H1 = 1  =>  0 pairs (X) / I2 = 1  =>  0 pairs (_)
H7,I8: 1.. / H7 = 1  =>  0 pairs (*) / I8 = 1  =>  0 pairs (X)
B1,H1: 1.. / B1 = 1  =>  0 pairs (*) / H1 = 1  =>  0 pairs (X)
C7,H7: 1.. / C7 = 1  =>  0 pairs (X) / H7 = 1  =>  0 pairs (_)
H1,H7: 1.. / H1 = 1  =>  0 pairs (X) / H7 = 1  =>  0 pairs (_)
I2,I8: 1.. / I2 = 1  =>  0 pairs (*) / I8 = 1  =>  0 pairs (X)
A1,A2: 2.. / A1 = 2  => 17 pairs (_) / A2 = 2  =>  0 pairs (X)
C7,C8: 2.. / C7 = 2  =>  0 pairs (*) / C8 = 2  =>  0 pairs (X)
H7,G8: 2.. / H7 = 2  =>  0 pairs (X) / G8 = 2  =>  0 pairs (_)
A1,G1: 2.. / A1 = 2  => 17 pairs (_) / G1 = 2  =>  0 pairs (X)
C7,H7: 2.. / C7 = 2  =>  0 pairs (*) / H7 = 2  =>  0 pairs (X)
C8,G8: 2.. / C8 = 2  =>  0 pairs (X) / G8 = 2  =>  0 pairs (_)
H2,H7: 2.. / H2 = 2  =>  0 pairs (*) / H7 = 2  =>  0 pairs (X)
D1,D2: 4.. / D1 = 4  =>  0 pairs (X) / D2 = 4  =>  0 pairs (_)
H1,I2: 4.. / H1 = 4  =>  0 pairs (*) / I2 = 4  =>  0 pairs (X)
C8,C9: 4.. / C8 = 4  =>  0 pairs (X) / C9 = 4  =>  0 pairs (_)
I8,H9: 4.. / I8 = 4  =>  0 pairs (*) / H9 = 4  =>  0 pairs (X)
D1,H1: 4.. / D1 = 4  =>  0 pairs (X) / H1 = 4  =>  0 pairs (_)
D2,I2: 4.. / D2 = 4  =>  0 pairs (*) / I2 = 4  =>  0 pairs (X)
C8,I8: 4.. / C8 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
C9,H9: 4.. / C9 = 4  =>  0 pairs (*) / H9 = 4  =>  0 pairs (X)
H1,H9: 4.. / H1 = 4  =>  0 pairs (*) / H9 = 4  =>  0 pairs (X)
I2,I8: 4.. / I2 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
B2,C2: 5.. / B2 = 5  =>  0 pairs (X) / C2 = 5  =>  0 pairs (_)
B5,C5: 5.. / B5 = 5  =>  0 pairs (*) / C5 = 5  =>  0 pairs (X)
B2,B5: 5.. / B2 = 5  =>  0 pairs (X) / B5 = 5  =>  0 pairs (_)
C2,C5: 5.. / C2 = 5  =>  0 pairs (*) / C5 = 5  =>  0 pairs (X)
B1,B2: 6.. / B1 = 6  =>  0 pairs (X) / B2 = 6  =>  0 pairs (_)
D1,D2: 6.. / D1 = 6  =>  0 pairs (*) / D2 = 6  =>  0 pairs (X)
B1,D1: 6.. / B1 = 6  =>  0 pairs (X) / D1 = 6  =>  0 pairs (_)
B2,D2: 6.. / B2 = 6  =>  0 pairs (*) / D2 = 6  =>  0 pairs (X)
G2,H2: 7.. / G2 = 7  =>  0 pairs (*) / H2 = 7  =>  0 pairs (X)
B5,C5: 7.. / B5 = 7  =>  0 pairs (X) / C5 = 7  =>  0 pairs (_)
G8,H9: 7.. / G8 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
C9,H9: 7.. / C9 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
B5,B8: 7.. / B5 = 7  =>  0 pairs (X) / B8 = 7  =>  0 pairs (_)
G2,G8: 7.. / G2 = 7  =>  0 pairs (*) / G8 = 7  =>  0 pairs (X)
H2,H9: 7.. / H2 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
A1,A2: 8.. / A1 = 8  =>  0 pairs (X) / A2 = 8  => 17 pairs (_)
G1,G2: 8.. / G1 = 8  => 17 pairs (_) / G2 = 8  =>  0 pairs (X)
A1,G1: 8.. / A1 = 8  =>  0 pairs (X) / G1 = 8  => 17 pairs (_)
A2,G2: 8.. / A2 = 8  => 17 pairs (_) / G2 = 8  =>  0 pairs (X)
* DURATION: 0:01:30.274061  START: 23:47:25.925235  END: 23:48:56.199296 2017-05-03
* CP COUNT: (42)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,B1,B5,B8,C2,C5,C7,C9,D1,D2,G1,G8,H1,H2,H7,H9,I2,I8)
* ..9.75..3....39...7432815969365124871..34896242896713538.7546.96..893.5.59.1263.8
* PAIR B1: 1,6 BLK 1
B2: 1,6,5                                # reduction candidate for 1,6
B2: 1,6 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
B2: 5 => CTR
* .69475.13.51639..47432815969365124871753489624289671353827546.96..893.5.59.1263.8
* PAIR A2: 2,8 ROW 2
G2: 2,8,7                                # reduction candidate for 2,8
G2: 2,8 => CTR
* ..9.75..3....39.7.7432815969365124871..34896242896713538.7546296.289375.59.1263.8
G2: 7 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* PAIR C2: 1,5 BLK 1
B2: 1,5,6                                # reduction candidate for 1,5
B2: 1,5 => CTR
* .69475.13...639..47432815969365124871..34896242896713538175462967.893.5.59.1263.8
B2: 6 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* PAIR G1: 2,8 BLK 3
G2: 2,8,7                                # reduction candidate for 2,8
G2: 2,8 => CTR
* ..9.75..3....39.7.7432815969365124871..34896242896713538.7546296.289375.59.1263.8
G2: 7 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* PAIR H2: 2,7 BLK 3
G2: 2,7,8                                # reduction candidate for 2,7
G2: 8 => CTR
* ..9.75..3....3987.7432815969365124871..34896242896713538.7546296.289375.59.1263.8
G2: 2,7                                  # 17 pairs
* PAIR C7: 1,2 BLK 7
C8: 1,2,4,7                              # reduction candidate for 1,2
C8: 1,2 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
C8: 4,7 => CTR
* ..9.75..3....39...7432815969365124871..34896242896713538275461961.893254594126378
* PAIR B8: 1,7 BLK 7
C8: 1,7,2,4                              # reduction candidate for 1,7
C8: 1,7 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
C8: 2,4                                  # 20 pairs
* PAIR C9: 4,7 BLK 7
C8: 4,7,1,2                              # reduction candidate for 4,7
C8: 4,7 => CTR
* ..9.75..3....39...7432815969365124871..34896242896713538275461961.893254594126378
C8: 1,2 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* PAIR G8: 2,7 ROW 8
C8: 2,7,1,4                              # reduction candidate for 2,7
C8: 2,7 => CTR
* ..9.75.43...4397217432815969365124871..34896242896713538.7546.96..893.54594126378
C8: 1,4 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* PAIR G8: 2,7 COL G
G2: 2,7,8                                # reduction candidate for 2,7
G2: 8 => CTR
* ..9.75..3....3987.7432815969365124871..34896242896713538.7546296.289375.59.1263.8
G2: 2,7                                  # 17 pairs
* PAIR I8: 1,4 ROW 8
C8: 1,4,2,7                              # reduction candidate for 1,4
C8: 1,4 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
C8: 2,7 => CTR
* ..9.75.43...4397217432815969365124871..34896242896713538.7546.96..893.54594126378
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-047-base-pr-000.dot
* REASONING
* PRF # B2: 1,6 => SOL
* DIS # B2: 5 => CTR => B2: 1,6
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* DIS # B2: 1,5 => CTR => B2: 6
* PRF # B2: 6 => SOL
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,2 => SOL
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,7 => SOL
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,2 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* PRF # C8: 1,4 => SOL
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,4 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* CNT  19 HDP CHAINS /  22 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,B1,B5,B8,C2,C5,C7,C9,D1,D2,G1,G8,H1,H2,H7,H9,I2,I8)
* ..9.75..3....39...7432815969365124871..34896242896713538.7546.96..893.5.59.1263.8
* PAIR B1: 1,6 BLK 1
B2: 1,6,5                                # reduction candidate for 1,6
B2: 1,6 => SOLVED
* 219675843865439721743281596936512487157348962428967135382754619671893254594126378
* DURATION: 0:00:02.242593  START: 23:49:27.539355  END: 23:49:29.781948 2017-05-03
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-047-base-pr-001.dot
* REASONING
* PRF # B2: 1,6 => SOL
* STA B2: 1,6
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 95 Sudokus 047
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 219675843865439721743281596936512487157348962428967135382754619671893254594126378 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:

* PRF # B2: 1,6 => SOL
* DIS # B2: 5 => CTR => B2: 1,6
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* DIS # B2: 1,5 => CTR => B2: 6
* PRF # B2: 6 => SOL
* DIS # G2: 2,8 => CTR => G2: 7
* PRF # G2: 7 => SOL
* INC # G2: 2,7 => UNS
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,2 => SOL
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,7 => SOL
* INC # C8: 2,4 => UNS
* DIS # C8: 4,7 => CTR => C8: 1,2
* PRF # C8: 1,2 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* PRF # C8: 1,4 => SOL
* INC # G2: 2,7 => UNS
* DIS # G2: 8 => CTR => G2: 2,7
* PRF # C8: 1,4 => SOL
* DIS # C8: 2,7 => CTR => C8: 1,4
* CNT  22 HDP CHAINS /  22 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # B2: 1,6 => SOL
* STA B2: 1,6
* CNT   1 HDP CHAINS /   1 HYP OPENED