Analysis of xx-top500-234-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .41......6...3.......2.....7..5....8.....4......1......2....91.....9.2..8....3... initial

Autosolve

position: 24195.83.69.43.5215.321.4.97325691481..3.4.929.41.23.532.84591.4...91283819.23.54 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # B5: 6,8 => SOL
* PRF # C8: 6,7 => SOL
* PRF # C8: 6,7 => SOL
* CNT  11 HDP CHAINS /  17 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 # F3: 7,8 => SOL
* STA F3: 7,8
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.41......6...3.......2.....7..5....8.....4......1......2....91.....9.2..8....3... initial
24195.83.69.43.5215.321.4.97325691481..3.4.929.41.23.532.84591.4...91283819.23.54 autosolve
241956837698437521573218469732569148185374692964182375327845916456791283819623754 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
C2: 7,8
B3: 7,8
F1: 6,7
F2: 7,8
I1: 6,7
H3: 6,7
B6: 6,8
E5: 7,8
E6: 7,8
G5: 6,7
H6: 6,7
C7: 6,7
D8: 6,7
D9: 6,7
I7: 6,7
G9: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B5,C5: 5.. / B5 = 5  => 18 pairs (_) / C5 = 5  =>  0 pairs (*)
B8,C8: 5.. / B8 = 5  =>  0 pairs (*) / C8 = 5  =>  0 pairs (X)
B5,B8: 5.. / B5 = 5  => 18 pairs (_) / B8 = 5  =>  0 pairs (*)
C5,C8: 5.. / C5 = 5  =>  0 pairs (*) / C8 = 5  =>  0 pairs (X)
F1,F3: 6.. / F1 = 6  =>  0 pairs (*) / F3 = 6  =>  0 pairs (X)
I1,H3: 6.. / I1 = 6  =>  0 pairs (X) / H3 = 6  =>  0 pairs (_)
G5,H6: 6.. / G5 = 6  =>  0 pairs (*) / H6 = 6  =>  0 pairs (X)
D8,D9: 6.. / D8 = 6  =>  0 pairs (X) / D9 = 6  =>  0 pairs (_)
I7,G9: 6.. / I7 = 6  =>  0 pairs (*) / G9 = 6  =>  0 pairs (X)
F1,I1: 6.. / F1 = 6  =>  0 pairs (*) / I1 = 6  =>  0 pairs (X)
F3,H3: 6.. / F3 = 6  =>  0 pairs (X) / H3 = 6  =>  0 pairs (_)
B6,H6: 6.. / B6 = 6  =>  0 pairs (*) / H6 = 6  =>  0 pairs (X)
C7,I7: 6.. / C7 = 6  =>  0 pairs (X) / I7 = 6  =>  0 pairs (_)
D9,G9: 6.. / D9 = 6  =>  0 pairs (*) / G9 = 6  =>  0 pairs (X)
G5,G9: 6.. / G5 = 6  =>  0 pairs (*) / G9 = 6  =>  0 pairs (X)
H3,H6: 6.. / H3 = 6  =>  0 pairs (*) / H6 = 6  =>  0 pairs (X)
I1,I7: 6.. / I1 = 6  =>  0 pairs (X) / I7 = 6  =>  0 pairs (_)
C2,B3: 7.. / C2 = 7  =>  0 pairs (X) / B3 = 7  =>  0 pairs (_)
I1,H3: 7.. / I1 = 7  =>  0 pairs (*) / H3 = 7  =>  0 pairs (X)
E5,E6: 7.. / E5 = 7  =>  0 pairs (*) / E6 = 7  =>  0 pairs (X)
G5,H6: 7.. / G5 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
D8,D9: 7.. / D8 = 7  =>  0 pairs (*) / D9 = 7  =>  0 pairs (X)
I7,G9: 7.. / I7 = 7  =>  0 pairs (X) / G9 = 7  =>  0 pairs (_)
F1,I1: 7.. / F1 = 7  =>  0 pairs (X) / I1 = 7  =>  0 pairs (_)
C2,F2: 7.. / C2 = 7  =>  0 pairs (X) / F2 = 7  =>  0 pairs (_)
E5,G5: 7.. / E5 = 7  =>  0 pairs (*) / G5 = 7  =>  0 pairs (X)
E6,H6: 7.. / E6 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
C7,I7: 7.. / C7 = 7  =>  0 pairs (*) / I7 = 7  =>  0 pairs (X)
D9,G9: 7.. / D9 = 7  =>  0 pairs (X) / G9 = 7  =>  0 pairs (_)
B3,B8: 7.. / B3 = 7  =>  0 pairs (*) / B8 = 7  =>  0 pairs (X)
G5,G9: 7.. / G5 = 7  =>  0 pairs (X) / G9 = 7  =>  0 pairs (_)
H3,H6: 7.. / H3 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
I1,I7: 7.. / I1 = 7  =>  0 pairs (*) / I7 = 7  =>  0 pairs (X)
C2,B3: 8.. / C2 = 8  =>  0 pairs (*) / B3 = 8  =>  0 pairs (X)
F2,F3: 8.. / F2 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
E5,E6: 8.. / E5 = 8  =>  0 pairs (X) / E6 = 8  =>  0 pairs (_)
C2,F2: 8.. / C2 = 8  =>  0 pairs (*) / F2 = 8  =>  0 pairs (X)
B3,F3: 8.. / B3 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
B6,E6: 8.. / B6 = 8  =>  0 pairs (X) / E6 = 8  =>  0 pairs (_)
C2,C5: 8.. / C2 = 8  =>  0 pairs (*) / C5 = 8  =>  0 pairs (X)
* DURATION: 0:01:05.700466  START: 10:49:47.796821  END: 10:50:53.497287 2017-05-04
* CP COUNT: (40)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B3,B6,C2,C7,D8,D9,E5,E6,F1,F2,G5,G9,H3,H6,I1,I7)
* 24195.83.69.43.5215.321.4.97325691481..3.4.929.41.23.532.84591.4...91283819.23.54
* PAIR B3: 7,8 ROW 3
F3: 7,8,6                                # reduction candidate for 7,8
F3: 7,8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
F3: 6 => CTR
* 24195.83.69.4385215832164797325691481.8374.929.41.23.532.84591.4...91283819.23.54
* PAIR F1: 6,7 BLK 2
F3: 6,7,8                                # reduction candidate for 6,7
F3: 6,7 => CTR
* 24195.83.69.43852158321.4.97325691481.837469296418237532.84591647..91283819.23.54
F3: 8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
* PAIR F2: 7,8 BLK 2
F3: 7,8,6                                # reduction candidate for 7,8
F3: 7,8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
F3: 6 => CTR
* 24195.83.69.4385215832164797325691481.8374.929.41.23.532.84591.4...91283819.23.54
* PAIR H3: 6,7 ROW 3
F3: 6,7,8                                # reduction candidate for 6,7
F3: 6,7 => CTR
* 24195.83.69.43852158321.4.97325691481.837469296418237532.84591647..91283819.23.54
F3: 8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
* PAIR B6: 6,8 BLK 4
B5: 6,8,5                                # reduction candidate for 6,8
B5: 6,8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
B5: 5                                    # 18 pairs
C5: 6,8,5                                # reduction candidate for 6,8
C5: 6,8                                  # 18 pairs
* PAIR C7: 6,7 BLK 7
B8: 6,7,5                                # reduction candidate for 6,7
B8: 6,7                                  # 18 pairs
C8: 6,7,5                                # reduction candidate for 6,7
C8: 6,7 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
C8: 5                                    # 18 pairs
* PAIR D8: 6,7 ROW 8
B8: 6,7,5                                # reduction candidate for 6,7
B8: 6,7                                  # 18 pairs
C8: 6,7,5                                # reduction candidate for 6,7
C8: 6,7 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
C8: 5                                    # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-234-base-pr-000.dot
* REASONING
* PRF # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # B5: 6,8 => SOL
* PRF # C8: 6,7 => SOL
* PRF # C8: 6,7 => SOL
* CNT  11 HDP CHAINS /  17 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B3,B6,C2,C7,D8,D9,E5,E6,F1,F2,G5,G9,H3,H6,I1,I7)
* 24195.83.69.43.5215.321.4.97325691481..3.4.929.41.23.532.84591.4...91283819.23.54
* PAIR B3: 7,8 ROW 3
F3: 7,8,6                                # reduction candidate for 7,8
F3: 7,8 => SOLVED
* 241956837698437521573218469732569148185374692964182375327845916456791283819623754
* DURATION: 0:00:01.918812  START: 10:51:12.646726  END: 10:51:14.565538 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-234-base-pr-001.dot
* REASONING
* PRF # F3: 7,8 => SOL
* STA F3: 7,8
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 234

solution: 241956837698437521573218469732569148185374692964182375327845916456791283819623754
info: 2067     FNWXY    S8.f     48635

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

Solution

position: 241956837698437521573218469732569148185374692964182375327845916456791283819623754 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 # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # F3: 7,8 => SOL
* DIS # F3: 6 => CTR => F3: 7,8
* DIS # F3: 6,7 => CTR => F3: 8
* PRF # F3: 8 => SOL
* PRF # B5: 6,8 => SOL
* INC # B5: 5 => UNS
* INC # C5: 6,8 => UNS
* INC # B8: 6,7 => UNS
* PRF # C8: 6,7 => SOL
* INC # C8: 5 => UNS
* INC # B8: 6,7 => UNS
* PRF # C8: 6,7 => SOL
* INC # C8: 5 => UNS
* CNT  17 HDP CHAINS /  17 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # F3: 7,8 => SOL
* STA F3: 7,8
* CNT   1 HDP CHAINS /   1 HYP OPENED