Analysis of xx-top500-349-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .7....2.3...1...........4.....5..61...32......4.......6...37...1......8.....4.... initial

Autosolve

position: .714..2.343.1.....26.3..4.17..5.3614.13264....4671..326...3714.1946..3873.7.41.26 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # C3: 5 => SOL
* DIS # F1: 8,9 => CTR => F1: 5,6
* PRF # C3: 5,9 => SOL
* DIS # C3: 8 => CTR => C3: 5,9
* DIS # G2: 5,9 => CTR => G2: 7,8
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* DIS # C4: 2 => CTR => C4: 8,9
* PRF # E3: 8,9 => SOL
* DIS # F1: 8,9 => CTR => F1: 5,6
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* DIS # B7: 2 => CTR => B7: 5,8
* DIS # G2: 5,9 => CTR => G2: 7,8
* DIS # G5: 5,9 => CTR => G5: 7,8
* CNT  15 HDP CHAINS /  46 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 # C3: 5 => SOL
* STA C3: 5
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.7....2.3...1...........4.....5..61...32......4.......6...37...1......8.....4.... initial
.714..2.343.1.....26.3..4.17..5.3614.13264....4671..326...3714.1946..3873.7.41.26 autosolve
871456293439172865265389471728593614913264758546718932652837149194625387387941526 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
A1: 8,9
C2: 5,9
B4: 2,8
E4: 8,9
F6: 8,9
C7: 2,8
B9: 5,8
D7: 8,9
E8: 2,5
F8: 2,5
D9: 8,9
I7: 5,9
G9: 5,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,F2: 2.. / E2 = 2  => 15 pairs (_) / F2 = 2  => 13 pairs (_)
B4,C4: 2.. / B4 = 2  => 13 pairs (_) / C4 = 2  =>  0 pairs (X)
B7,C7: 2.. / B7 = 2  =>  0 pairs (X) / C7 = 2  => 13 pairs (_)
E8,F8: 2.. / E8 = 2  => 13 pairs (_) / F8 = 2  => 15 pairs (_)
B4,B7: 2.. / B4 = 2  => 13 pairs (_) / B7 = 2  =>  0 pairs (X)
C4,C7: 2.. / C4 = 2  =>  0 pairs (X) / C7 = 2  => 13 pairs (_)
E2,E8: 2.. / E2 = 2  => 15 pairs (_) / E8 = 2  => 13 pairs (_)
F2,F8: 2.. / F2 = 2  => 13 pairs (_) / F8 = 2  => 15 pairs (_)
C2,C3: 5.. / C2 = 5  => 15 pairs (_) / C3 = 5  =>  0 pairs (*)
A5,A6: 5.. / A5 = 5  => 15 pairs (_) / A6 = 5  => 15 pairs (_)
B7,B9: 5.. / B7 = 5  => 11 pairs (_) / B9 = 5  => 13 pairs (_)
E8,F8: 5.. / E8 = 5  => 15 pairs (_) / F8 = 5  => 13 pairs (_)
I7,G9: 5.. / I7 = 5  => 13 pairs (_) / G9 = 5  => 11 pairs (_)
A6,G6: 5.. / A6 = 5  => 15 pairs (_) / G6 = 5  => 15 pairs (_)
B7,I7: 5.. / B7 = 5  => 11 pairs (_) / I7 = 5  => 13 pairs (_)
B9,G9: 5.. / B9 = 5  => 13 pairs (_) / G9 = 5  => 11 pairs (_)
F1,F2: 6.. / F1 = 6  => 14 pairs (_) / F2 = 6  => 14 pairs (_)
H1,H2: 6.. / H1 = 6  => 14 pairs (_) / H2 = 6  => 14 pairs (_)
F1,H1: 6.. / F1 = 6  => 14 pairs (_) / H1 = 6  => 14 pairs (_)
F2,H2: 6.. / F2 = 6  => 14 pairs (_) / H2 = 6  => 14 pairs (_)
E2,E3: 7.. / E2 = 7  => 14 pairs (_) / E3 = 7  => 14 pairs (_)
G5,H5: 7.. / G5 = 7  => 17 pairs (_) / H5 = 7  => 15 pairs (_)
E3,H3: 7.. / E3 = 7  => 14 pairs (_) / H3 = 7  => 14 pairs (_)
G2,G5: 7.. / G2 = 7  => 15 pairs (_) / G5 = 7  => 17 pairs (_)
A1,C3: 8.. / A1 = 8  =>  0 pairs (*) / C3 = 8  =>  0 pairs (X)
G2,I2: 8.. / G2 = 8  => 20 pairs (_) / I2 = 8  => 14 pairs (_)
E4,F6: 8.. / E4 = 8  =>  0 pairs (X) / F6 = 8  =>  0 pairs (_)
D7,D9: 8.. / D7 = 8  => 11 pairs (_) / D9 = 8  => 13 pairs (_)
B9,D9: 8.. / B9 = 8  => 11 pairs (_) / D9 = 8  => 13 pairs (_)
I2,I5: 8.. / I2 = 8  => 14 pairs (_) / I5 = 8  => 20 pairs (_)
E4,F6: 9.. / E4 = 9  =>  0 pairs (*) / F6 = 9  =>  0 pairs (X)
D7,D9: 9.. / D7 = 9  => 13 pairs (_) / D9 = 9  => 11 pairs (_)
I7,G9: 9.. / I7 = 9  => 11 pairs (_) / G9 = 9  => 13 pairs (_)
C4,E4: 9.. / C4 = 9  =>  0 pairs (X) / E4 = 9  =>  0 pairs (_)
D7,I7: 9.. / D7 = 9  => 13 pairs (_) / I7 = 9  => 11 pairs (_)
D9,G9: 9.. / D9 = 9  => 11 pairs (_) / G9 = 9  => 13 pairs (_)
* DURATION: 0:01:06.221584  START: 14:39:49.700608  END: 14:40:55.922192 2017-05-04
* CP COUNT: (36)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B4,B9,C2,C7,D7,D9,E4,E8,F6,F8,G9,I7)
* .714..2.343.1.....26.3..4.17..5.3614.13264....4671..326...3714.1946..3873.7.41.26
* PAIR A1: 8,9 BLK 1
C3: 8,9,5                                # reduction candidate for 8,9
C3: 5 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
C3: 8,9                                  # 15 pairs
* PAIR A1: 8,9 ROW 1
E1: 8,9,5                                # reduction candidate for 8,9
E1: 8,9                                  # 17 pairs
F1: 8,9,5,6                              # reduction candidate for 8,9
F1: 8,9 => CTR
* .7145.26343.1.6...26.3..4.17..5.3614.13264....4671..326...3714.1946.23873.7.41.26
F1: 5,6                                  # 14 pairs
* PAIR A1: 8,9 COL A
A5: 8,9,5                                # reduction candidate for 8,9
A5: 8,9                                  # 15 pairs
A6: 8,9,5                                # reduction candidate for 8,9
A6: 8,9                                  # 15 pairs
* PAIR C2: 5,9 BLK 1
C3: 5,9,8                                # reduction candidate for 5,9
C3: 5,9 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
C3: 8 => CTR
* 97145.2.34351.....2683..4.17.9583614.13264....46719.326.2.3714.1946..3873.7.41.26
* PAIR C2: 5,9 ROW 2
E2: 5,9,2,7                              # reduction candidate for 5,9
E2: 5,9                                  # 16 pairs
F2: 5,9,2,6                              # reduction candidate for 5,9
F2: 5,9                                  # 16 pairs
G2: 5,9,7,8                              # reduction candidate for 5,9
G2: 5,9 => CTR
* 9714582.343.1....826.3..4.17..5836148132647..5467198326...3714.1946..3873.7.41.26
G2: 7,8                                  # 14 pairs
H2: 5,9,6,7                              # reduction candidate for 5,9
H2: 5,9                                  # 16 pairs
I2: 5,9,8                                # reduction candidate for 5,9
I2: 5,9                                  # 20 pairs
* PAIR B4: 2,8 BLK 4
C4: 2,8,9                                # reduction candidate for 2,8
C4: 2,8 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
C4: 9 => CTR
* 9714582.343.1.....26.3..4.1729583614.13264....46719.326.2.3714.1946..3873.7.41.26
* PAIR B4: 2,8 COL B
B7: 2,8,5                                # reduction candidate for 2,8
B7: 2,8                                  # 13 pairs
B7: 5                                    # 11 pairs
* PAIR E4: 8,9 ROW 4
C4: 8,9,2                                # reduction candidate for 8,9
C4: 2 => CTR
* 87145629343.1.....26.389471782593614.132647.8946718532628937145194625387357841926
C4: 8,9                                  # 13 pairs
* PAIR E4: 8,9 COL E
E1: 8,9,5                                # reduction candidate for 8,9
E1: 8,9                                  # 17 pairs
E3: 8,9,5,7                              # reduction candidate for 8,9
E3: 8,9 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
E3: 5,7                                  # 14 pairs
* PAIR F6: 8,9 ROW 6
A6: 8,9,5                                # reduction candidate for 8,9
A6: 8,9                                  # 15 pairs
G6: 8,9,5                                # reduction candidate for 8,9
G6: 8,9                                  # 15 pairs
* PAIR F6: 8,9 COL F
F1: 8,9,5,6                              # reduction candidate for 8,9
F1: 8,9 => CTR
* .7145.26343.1.6...26.3..4.17..5.3614.13264....4671..326...3714.1946.23873.7.41.26
F1: 5,6                                  # 14 pairs
F3: 8,9,5                                # reduction candidate for 8,9
F3: 8,9                                  # 15 pairs
* PAIR C7: 2,8 BLK 7
B7: 2,8,5                                # reduction candidate for 2,8
B7: 2,8                                  # 13 pairs
B7: 5                                    # 11 pairs
* PAIR C7: 2,8 COL C
C4: 2,8,9                                # reduction candidate for 2,8
C4: 2,8 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
C4: 9 => CTR
* 9714582.343.1.....26.3..4.1729583614.13264....46719.326.2.3714.1946..3873.7.41.26
* PAIR B9: 5,8 BLK 7
B7: 5,8,2                                # reduction candidate for 5,8
B7: 2 => CTR
* 87145.2.343.1.....26.389471782593614513264798946718532628937145194625387357841926
B7: 5,8                                  # 13 pairs
* PAIR E8: 2,5 COL E
E2: 2,5,7,9                              # reduction candidate for 2,5
E2: 2,5                                  # 18 pairs
E2: 7,9                                  # 14 pairs
* PAIR F8: 2,5 COL F
F2: 2,5,6,9                              # reduction candidate for 2,5
F2: 6,9                                  # 16 pairs
F2: 2,5                                  # 16 pairs
* PAIR I7: 5,9 COL I
I2: 5,9,8                                # reduction candidate for 5,9
I2: 5,9                                  # 20 pairs
I5: 5,9,8                                # reduction candidate for 5,9
I5: 5,9                                  # 14 pairs
* PAIR G9: 5,9 COL G
G2: 5,9,7,8                              # reduction candidate for 5,9
G2: 5,9 => CTR
* 9714582.343.1....826.3..4.17..5836148132647..5467198326...3714.1946..3873.7.41.26
G2: 7,8                                  # 14 pairs
G5: 5,9,7,8                              # reduction candidate for 5,9
G5: 5,9 => CTR
* 9714..2.34351..7.826837.4.1729583614813264.7.5467198326.2.3714.1946..3873.7.41.26
G5: 7,8                                  # 14 pairs
G6: 5,9,8                                # reduction candidate for 5,9
G6: 5,9                                  # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-349-base-pr-000.dot
* REASONING
* PRF # C3: 5 => SOL
* DIS # F1: 8,9 => CTR => F1: 5,6
* PRF # C3: 5,9 => SOL
* DIS # C3: 8 => CTR => C3: 5,9
* DIS # G2: 5,9 => CTR => G2: 7,8
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* DIS # C4: 2 => CTR => C4: 8,9
* PRF # E3: 8,9 => SOL
* DIS # F1: 8,9 => CTR => F1: 5,6
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* DIS # B7: 2 => CTR => B7: 5,8
* DIS # G2: 5,9 => CTR => G2: 7,8
* DIS # G5: 5,9 => CTR => G5: 7,8
* CNT  15 HDP CHAINS /  46 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B4,B9,C2,C7,D7,D9,E4,E8,F6,F8,G9,I7)
* .714..2.343.1.....26.3..4.17..5.3614.13264....4671..326...3714.1946..3873.7.41.26
* PAIR A1: 8,9 BLK 1
C3: 8,9,5                                # reduction candidate for 8,9
C3: 5 => SOLVED
* 871456293439172865265389471728593614913264758546718932652837149194625387387941526
* DURATION: 0:00:03.067461  START: 14:41:41.660710  END: 14:41:44.728171 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-349-base-pr-001.dot
* REASONING
* PRF # C3: 5 => SOL
* STA C3: 5
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 349

solution: 871456293439172865265389471728593614913264758546718932652837149194625387387941526
info: 4882     FNBWX    S8.f     22179

http://www.sfsudoku.com/su17ExtremeDiff500.txt from http://www.minimumsudoku.com/

Solution

position: 871456293439172865265389471728593614913264758546718932652837149194625387387941526 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 # C3: 8,9 => UNS
* PRF # C3: 5 => SOL
* INC # E1: 8,9 => UNS
* DIS # F1: 8,9 => CTR => F1: 5,6
* INC # F1: 5,6 => UNS
* INC # A5: 8,9 => UNS
* INC # A6: 8,9 => UNS
* PRF # C3: 5,9 => SOL
* DIS # C3: 8 => CTR => C3: 5,9
* INC # E2: 5,9 => UNS
* INC # F2: 5,9 => UNS
* DIS # G2: 5,9 => CTR => G2: 7,8
* INC # G2: 7,8 => UNS
* INC # H2: 5,9 => UNS
* INC # I2: 5,9 => UNS
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* INC # B7: 2,8 => UNS
* INC # B7: 5 => UNS
* INC # C4: 8,9 => UNS
* DIS # C4: 2 => CTR => C4: 8,9
* INC # E1: 8,9 => UNS
* PRF # E3: 8,9 => SOL
* INC # E3: 5,7 => UNS
* INC # A6: 8,9 => UNS
* INC # G6: 8,9 => UNS
* DIS # F1: 8,9 => CTR => F1: 5,6
* INC # F1: 5,6 => UNS
* INC # F3: 8,9 => UNS
* INC # B7: 2,8 => UNS
* INC # B7: 5 => UNS
* PRF # C4: 2,8 => SOL
* DIS # C4: 9 => CTR => C4: 2,8
* INC # B7: 5,8 => UNS
* DIS # B7: 2 => CTR => B7: 5,8
* INC # E2: 2,5 => UNS
* INC # E2: 7,9 => UNS
* INC # F2: 2,5 => UNS
* INC # F2: 6,9 => UNS
* INC # I2: 5,9 => UNS
* INC # I5: 5,9 => UNS
* DIS # G2: 5,9 => CTR => G2: 7,8
* INC # G2: 7,8 => UNS
* DIS # G5: 5,9 => CTR => G5: 7,8
* INC # G5: 7,8 => UNS
* INC # G6: 5,9 => UNS
* CNT  46 HDP CHAINS /  46 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C3: 8,9 => UNS
* PRF # C3: 5 => SOL
* STA C3: 5
* CNT   2 HDP CHAINS /   2 HYP OPENED