Analysis of xx-top500-166-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ......1.27..4...........8..3.....64.4....9.......1.....126........5...3..9....... initial

Autosolve

position: 9.....1.27.64.13951.59..8.43.12..64945..6921.269.1475.5126934876..5..931893147526 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B1: 4,8 => CTR => B1: 3
* PRF # B1: 3 => SOL
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 3,7 => SOL
* DIS # E1: 5 => CTR => E1: 3,7
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 5,7 => SOL
* DIS # E1: 3 => CTR => E1: 5,7
* PRF # F1: 5,8 => SOL
* DIS # F1: 6 => CTR => F1: 5,8
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* CNT  14 HDP CHAINS /  16 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 # B1: 4,8 => CTR => B1: 3
* PRF B1: 3 => SOL
* STA B1: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

......1.27..4...........8..3.....64.4....9.......1.....126........5...3..9....... initial
9.....1.27.64.13951.59..8.43.12..64945..6921.269.1475.5126934876..5..931893147526 autosolve
934875162786421395125936874371258649458769213269314758512693487647582931893147526 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (20)
C1: 4,8
B2: 2,8
B3: 2,3
D1: 7,8
E2: 2,8
E3: 3,7
F3: 2,6
H1: 6,7
H3: 6,7
B4: 7,8
C5: 7,8
E4: 5,7
F4: 5,8
D6: 3,8
I5: 3,8
I6: 3,8
B8: 4,7
C8: 4,7
E8: 2,8
F8: 2,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,B3: 2.. / B2 = 2  =>  0 pairs (X) / B3 = 2  =>  0 pairs (_)
E2,F3: 2.. / E2 = 2  =>  0 pairs (*) / F3 = 2  =>  0 pairs (X)
E8,F8: 2.. / E8 = 2  =>  0 pairs (X) / F8 = 2  =>  0 pairs (_)
B2,E2: 2.. / B2 = 2  =>  0 pairs (X) / E2 = 2  =>  0 pairs (_)
B3,F3: 2.. / B3 = 2  =>  0 pairs (*) / F3 = 2  =>  0 pairs (X)
E2,E8: 2.. / E2 = 2  =>  0 pairs (*) / E8 = 2  =>  0 pairs (X)
F3,F8: 2.. / F3 = 2  =>  0 pairs (X) / F8 = 2  =>  0 pairs (_)
B1,B3: 3.. / B1 = 3  =>  0 pairs (*) / B3 = 3  =>  0 pairs (X)
E1,E3: 3.. / E1 = 3  =>  0 pairs (X) / E3 = 3  =>  0 pairs (_)
D5,D6: 3.. / D5 = 3  =>  0 pairs (X) / D6 = 3  => 18 pairs (_)
I5,I6: 3.. / I5 = 3  => 18 pairs (_) / I6 = 3  =>  0 pairs (X)
B1,E1: 3.. / B1 = 3  =>  0 pairs (*) / E1 = 3  =>  0 pairs (X)
B3,E3: 3.. / B3 = 3  =>  0 pairs (X) / E3 = 3  =>  0 pairs (_)
D5,I5: 3.. / D5 = 3  =>  0 pairs (X) / I5 = 3  => 18 pairs (_)
D6,I6: 3.. / D6 = 3  => 18 pairs (_) / I6 = 3  =>  0 pairs (X)
B1,C1: 4.. / B1 = 4  =>  0 pairs (X) / C1 = 4  =>  0 pairs (_)
B8,C8: 4.. / B8 = 4  =>  0 pairs (*) / C8 = 4  =>  0 pairs (X)
B1,B8: 4.. / B1 = 4  =>  0 pairs (X) / B8 = 4  =>  0 pairs (_)
C1,C8: 4.. / C1 = 4  =>  0 pairs (*) / C8 = 4  =>  0 pairs (X)
E1,F1: 5.. / E1 = 5  =>  0 pairs (X) / F1 = 5  =>  0 pairs (_)
E4,F4: 5.. / E4 = 5  =>  0 pairs (*) / F4 = 5  =>  0 pairs (X)
E1,E4: 5.. / E1 = 5  =>  0 pairs (X) / E4 = 5  =>  0 pairs (_)
F1,F4: 5.. / F1 = 5  =>  0 pairs (*) / F4 = 5  =>  0 pairs (X)
F1,F3: 6.. / F1 = 6  =>  0 pairs (X) / F3 = 6  =>  0 pairs (_)
H1,H3: 6.. / H1 = 6  =>  0 pairs (*) / H3 = 6  =>  0 pairs (X)
F1,H1: 6.. / F1 = 6  =>  0 pairs (X) / H1 = 6  =>  0 pairs (_)
F3,H3: 6.. / F3 = 6  =>  0 pairs (*) / H3 = 6  =>  0 pairs (X)
H1,H3: 7.. / H1 = 7  =>  0 pairs (X) / H3 = 7  =>  0 pairs (_)
B4,C5: 7.. / B4 = 7  =>  0 pairs (*) / C5 = 7  =>  0 pairs (X)
E4,D5: 7.. / E4 = 7  =>  0 pairs (X) / D5 = 7  =>  0 pairs (_)
B8,C8: 7.. / B8 = 7  =>  0 pairs (X) / C8 = 7  =>  0 pairs (_)
E3,H3: 7.. / E3 = 7  =>  0 pairs (X) / H3 = 7  =>  0 pairs (_)
B4,E4: 7.. / B4 = 7  =>  0 pairs (*) / E4 = 7  =>  0 pairs (X)
C5,D5: 7.. / C5 = 7  =>  0 pairs (X) / D5 = 7  =>  0 pairs (_)
B4,B8: 7.. / B4 = 7  =>  0 pairs (*) / B8 = 7  =>  0 pairs (X)
C5,C8: 7.. / C5 = 7  =>  0 pairs (X) / C8 = 7  =>  0 pairs (_)
D1,D5: 7.. / D1 = 7  =>  0 pairs (X) / D5 = 7  =>  0 pairs (_)
B4,C5: 8.. / B4 = 8  =>  0 pairs (X) / C5 = 8  =>  0 pairs (_)
I5,I6: 8.. / I5 = 8  =>  0 pairs (X) / I6 = 8  => 18 pairs (_)
E8,F8: 8.. / E8 = 8  =>  0 pairs (*) / F8 = 8  =>  0 pairs (X)
B2,E2: 8.. / B2 = 8  =>  0 pairs (*) / E2 = 8  =>  0 pairs (X)
B4,F4: 8.. / B4 = 8  =>  0 pairs (X) / F4 = 8  =>  0 pairs (_)
D6,I6: 8.. / D6 = 8  =>  0 pairs (X) / I6 = 8  => 18 pairs (_)
C1,C5: 8.. / C1 = 8  =>  0 pairs (X) / C5 = 8  =>  0 pairs (_)
E2,E8: 8.. / E2 = 8  =>  0 pairs (X) / E8 = 8  =>  0 pairs (_)
* DURATION: 0:01:31.674275  START: 08:25:14.034728  END: 08:26:45.709003 2017-05-04
* CP COUNT: (45)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B3,B4,B8,C1,C5,C8,D1,D6,E2,E3,E4,E8,F3,F4,F8,H1,H3,I5,I6)
* 9.....1.27.64.13951.59..8.43.12..64945..6921.269.1475.5126934876..5..931893147526
* PAIR C1: 4,8 BLK 1
B1: 4,8,3                                # reduction candidate for 4,8
B1: 4,8 => CTR
* 9...351627.64.139513597.8.43.12..64945..6921.269.1475.5126934876..5..931893147526
B1: 3 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
* PAIR D1: 7,8 COL D
D5: 7,8,3                                # reduction candidate for 7,8
D5: 3 => CTR
* 9..7..1627.64.13951.59368743.12756494573692182698147535126934876745.2931893147526
D5: 7,8                                  # 18 pairs
* PAIR E3: 3,7 BLK 2
E1: 3,7,5                                # reduction candidate for 3,7
E1: 3,7 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
E1: 5 => CTR
* 934.5.1.27864213951259368.43.12..64945..6921.269.1475.5126934876..5..931893147526
* PAIR C5: 7,8 ROW 5
D5: 7,8,3                                # reduction candidate for 7,8
D5: 3 => CTR
* 9..7..1627.64.13951.59368743.12756494573692182698147535126934876745.2931893147526
D5: 7,8                                  # 18 pairs
* PAIR E4: 5,7 COL E
E1: 5,7,3                                # reduction candidate for 5,7
E1: 5,7 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
E1: 3 => CTR
* 9...351627.64.139513597.8.43.12..64945..6921.269.1475.5126934876..5..931893147526
* PAIR F4: 5,8 COL F
F1: 5,8,6                                # reduction candidate for 5,8
F1: 5,8 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
F1: 6 => CTR
* 9...561727.64.13951.59..8.43.12..64945..6921.269.1475.5126934876..5..931893147526
* PAIR D6: 3,8 BLK 5
D5: 3,8,7                                # reduction candidate for 3,8
D5: 3,8 => CTR
* 9..7..1627.64.13951.59368743.1275649457.6921.269.1475.5126934876745.2931893147526
D5: 7 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
* PAIR I5: 3,8 ROW 5
D5: 3,8,7                                # reduction candidate for 3,8
D5: 3,8 => CTR
* 9..7..1627.64.13951.59368743.1275649457.6921.269.1475.5126934876745.2931893147526
D5: 7 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-166-base-pr-000.dot
* REASONING
* DIS # B1: 4,8 => CTR => B1: 3
* PRF # B1: 3 => SOL
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 3,7 => SOL
* DIS # E1: 5 => CTR => E1: 3,7
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 5,7 => SOL
* DIS # E1: 3 => CTR => E1: 5,7
* PRF # F1: 5,8 => SOL
* DIS # F1: 6 => CTR => F1: 5,8
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* CNT  14 HDP CHAINS /  16 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B3,B4,B8,C1,C5,C8,D1,D6,E2,E3,E4,E8,F3,F4,F8,H1,H3,I5,I6)
* 9.....1.27.64.13951.59..8.43.12..64945..6921.269.1475.5126934876..5..931893147526
* PAIR C1: 4,8 BLK 1
B1: 4,8,3                                # reduction candidate for 4,8
B1: 4,8 => CTR
* 9...351627.64.139513597.8.43.12..64945..6921.269.1475.5126934876..5..931893147526
B1: 3 => SOLVED
* 934875162786421395125936874371258649458769213269314758512693487647582931893147526
* DURATION: 0:00:03.172992  START: 08:27:07.362236  END: 08:27:10.535228 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-166-base-pr-001.dot
* REASONING
* DIS # B1: 4,8 => CTR => B1: 3
* PRF B1: 3 => SOL
* STA B1: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 166

solution: 934875162786421395125936874371258649458769213269314758512693487647582931893147526
info: 1824     FNBTWY   S8.f     836

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

Solution

position: 934875162786421395125936874371258649458769213269314758512693487647582931893147526 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:

* DIS # B1: 4,8 => CTR => B1: 3
* PRF # B1: 3 => SOL
* INC # D5: 7,8 => UNS
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 3,7 => SOL
* DIS # E1: 5 => CTR => E1: 3,7
* INC # D5: 7,8 => UNS
* DIS # D5: 3 => CTR => D5: 7,8
* PRF # E1: 5,7 => SOL
* DIS # E1: 3 => CTR => E1: 5,7
* PRF # F1: 5,8 => SOL
* DIS # F1: 6 => CTR => F1: 5,8
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* DIS # D5: 3,8 => CTR => D5: 7
* PRF # D5: 7 => SOL
* CNT  16 HDP CHAINS /  16 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B1: 4,8 => CTR => B1: 3
* PRF B1: 3 => SOL
* STA B1: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED