Analysis of xx-top500-455-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....94.3.51................6.3..8......7..9........1.....5...2....6....84...1.... initial

Autosolve

position: ....9453151.376.94....51.76693128745...7.59.....4.91.....58.429...64.3184..91.657 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C7: 6,7 => CTR => C7: 1
* PRF # C7: 1 => SOL
* PRF # C8: 5,7 => SOL
* DIS # C8: 9 => CTR => C8: 5,7
* PRF # B9: 3 => SOL
* PRF # A7: 3,7 => SOL
* DIS # A7: 1 => CTR => A7: 3,7
* DIS # B7: 3,7 => CTR => B7: 6
* DIS # A8: 2,7 => CTR => A8: 9
* PRF # A8: 9 => SOL
* PRF # B8: 2,7 => SOL
* CNT  11 HDP CHAINS /  24 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 # C7: 6,7 => CTR => C7: 1
* PRF C7: 1 => SOL
* STA C7: 1
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

....94.3.51................6.3..8......7..9........1.....5...2....6....84...1.... initial
....9453151.376.94....51.76693128745...7.59.....4.91.....58.429...64.3184..91.657 autosolve
876294531512376894349851276693128745184735962257469183761583429925647318438912657 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (21)
C1: 6,7
C2: 2,8
A3: 3,9
B3: 3,4
C3: 4,9
D1: 2,8
D3: 2,8
G2: 2,8
G3: 2,8
C5: 1,4
C6: 5,7
E5: 3,6
E6: 3,6
H5: 6,8
I5: 2,3
H6: 6,8
I6: 2,3
C9: 2,8
F7: 3,7
F8: 2,7
F9: 2,3

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A5,C5: 1.. / A5 = 1  =>  0 pairs (*) / C5 = 1  =>  0 pairs (X)
A7,C7: 1.. / A7 = 1  =>  0 pairs (X) / C7 = 1  =>  0 pairs (_)
A5,A7: 1.. / A5 = 1  =>  0 pairs (*) / A7 = 1  =>  0 pairs (X)
C5,C7: 1.. / C5 = 1  =>  0 pairs (X) / C7 = 1  =>  0 pairs (_)
D1,D3: 2.. / D1 = 2  => 17 pairs (_) / D3 = 2  => 19 pairs (_)
G2,G3: 2.. / G2 = 2  => 19 pairs (_) / G3 = 2  => 17 pairs (_)
I5,I6: 2.. / I5 = 2  => 18 pairs (_) / I6 = 2  => 18 pairs (_)
F8,F9: 2.. / F8 = 2  => 24 pairs (_) / F9 = 2  =>  0 pairs (*)
C2,G2: 2.. / C2 = 2  => 17 pairs (_) / G2 = 2  => 19 pairs (_)
D3,G3: 2.. / D3 = 2  => 19 pairs (_) / G3 = 2  => 17 pairs (_)
C2,C9: 2.. / C2 = 2  => 17 pairs (_) / C9 = 2  => 19 pairs (_)
A3,B3: 3.. / A3 = 3  =>  0 pairs (*) / B3 = 3  =>  0 pairs (X)
E5,E6: 3.. / E5 = 3  => 18 pairs (_) / E6 = 3  => 18 pairs (_)
I5,I6: 3.. / I5 = 3  => 18 pairs (_) / I6 = 3  => 18 pairs (_)
F7,F9: 3.. / F7 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
E5,I5: 3.. / E5 = 3  => 18 pairs (_) / I5 = 3  => 18 pairs (_)
E6,I6: 3.. / E6 = 3  => 18 pairs (_) / I6 = 3  => 18 pairs (_)
B9,F9: 3.. / B9 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
A3,A7: 3.. / A3 = 3  =>  0 pairs (*) / A7 = 3  =>  0 pairs (X)
B3,C3: 4.. / B3 = 4  =>  0 pairs (*) / C3 = 4  =>  0 pairs (X)
B5,C5: 4.. / B5 = 4  =>  0 pairs (X) / C5 = 4  =>  0 pairs (_)
B3,B5: 4.. / B3 = 4  =>  0 pairs (*) / B5 = 4  =>  0 pairs (X)
C3,C5: 4.. / C3 = 4  =>  0 pairs (X) / C5 = 4  =>  0 pairs (_)
B6,C6: 5.. / B6 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
B8,C8: 5.. / B8 = 5  => 21 pairs (_) / C8 = 5  =>  0 pairs (*)
B6,B8: 5.. / B6 = 5  =>  0 pairs (*) / B8 = 5  =>  0 pairs (X)
C6,C8: 5.. / C6 = 5  => 21 pairs (_) / C8 = 5  =>  0 pairs (*)
B1,C1: 6.. / B1 = 6  =>  0 pairs (X) / C1 = 6  => 21 pairs (_)
E5,E6: 6.. / E5 = 6  => 18 pairs (_) / E6 = 6  => 18 pairs (_)
H5,H6: 6.. / H5 = 6  => 18 pairs (_) / H6 = 6  => 18 pairs (_)
B7,C7: 6.. / B7 = 6  => 21 pairs (_) / C7 = 6  =>  0 pairs (X)
E5,H5: 6.. / E5 = 6  => 18 pairs (_) / H5 = 6  => 18 pairs (_)
E6,H6: 6.. / E6 = 6  => 18 pairs (_) / H6 = 6  => 18 pairs (_)
B1,B7: 6.. / B1 = 6  =>  0 pairs (X) / B7 = 6  => 21 pairs (_)
C1,C7: 6.. / C1 = 6  => 21 pairs (_) / C7 = 6  =>  0 pairs (X)
F7,F8: 7.. / F7 = 7  => 24 pairs (_) / F8 = 7  =>  0 pairs (*)
D1,D3: 8.. / D1 = 8  => 19 pairs (_) / D3 = 8  => 17 pairs (_)
G2,G3: 8.. / G2 = 8  => 17 pairs (_) / G3 = 8  => 19 pairs (_)
H5,H6: 8.. / H5 = 8  => 18 pairs (_) / H6 = 8  => 18 pairs (_)
B9,C9: 8.. / B9 = 8  => 19 pairs (_) / C9 = 8  => 17 pairs (_)
C2,G2: 8.. / C2 = 8  => 19 pairs (_) / G2 = 8  => 17 pairs (_)
D3,G3: 8.. / D3 = 8  => 17 pairs (_) / G3 = 8  => 19 pairs (_)
C2,C9: 8.. / C2 = 8  => 19 pairs (_) / C9 = 8  => 17 pairs (_)
A3,C3: 9.. / A3 = 9  =>  0 pairs (X) / C3 = 9  =>  0 pairs (_)
A8,C8: 9.. / A8 = 9  =>  0 pairs (*) / C8 = 9  =>  0 pairs (X)
A3,A8: 9.. / A3 = 9  =>  0 pairs (X) / A8 = 9  =>  0 pairs (_)
C3,C8: 9.. / C3 = 9  =>  0 pairs (*) / C8 = 9  =>  0 pairs (X)
* DURATION: 0:01:42.138601  START: 18:16:50.892134  END: 18:18:33.030735 2017-05-04
* CP COUNT: (47)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B3,C1,C2,C3,C5,C6,C9,D1,D3,E5,E6,F7,F8,F9,G2,G3,H5,H6,I5,I6)
* ....9453151.376.94....51.76693128745...7.59.....4.91.....58.429...64.3184..91.657
* PAIR C1: 6,7 BLK 1
B1: 6,7,2,8                              # reduction candidate for 6,7
B1: 2,8                                  # 28 pairs
B1: 6,7                                  # 23 pairs
* PAIR C1: 6,7 COL C
C7: 6,7,1                                # reduction candidate for 6,7
C7: 6,7 => CTR
* ....9453151.376.9434..51.76693128745..17.59.....4.91..1..58.429...64.3184..91.657
C7: 1 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
* PAIR C2: 2,8 BLK 1
A1: 2,8,7                                # reduction candidate for 2,8
A1: 2,8                                  # 23 pairs
B1: 2,8,6,7                              # reduction candidate for 2,8
B1: 2,8                                  # 28 pairs
* PAIR D1: 2,8 ROW 1
A1: 2,8,7                                # reduction candidate for 2,8
A1: 2,8                                  # 23 pairs
B1: 2,8,6,7                              # reduction candidate for 2,8
B1: 2,8                                  # 28 pairs
* PAIR C6: 5,7 BLK 4
B6: 5,7,2,8                              # reduction candidate for 5,7
B6: 2,8                                  # 27 pairs
B6: 5,7                                  # 23 pairs
* PAIR C6: 5,7 COL C
C8: 5,7,9                                # reduction candidate for 5,7
C8: 5,7 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
C8: 9 => CTR
* ....9453151.376.94934.51.76693128745.417.59....54.91.....58.429.5964.3184..91.657
* PAIR C9: 2,8 BLK 7
B9: 2,8,3                                # reduction candidate for 2,8
B9: 3 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
B9: 2,8                                  # 24 pairs
* PAIR F7: 3,7 ROW 7
A7: 3,7,1                                # reduction candidate for 3,7
A7: 3,7 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
A7: 1 => CTR
* ....9453151.376.94349.51.76693128745..47.59.....4.91..1..58.4299..64.3184..91.657
B7: 3,7,6                                # reduction candidate for 3,7
B7: 3,7 => CTR
* .67.9453151.376.94934.51.76693128745.417.59....54.91....658.429.5964.3184..91.657
B7: 6                                    # 21 pairs
* PAIR F8: 2,7 ROW 8
A8: 2,7,9                                # reduction candidate for 2,7
A8: 2,7 => CTR
* ....9453151.376.94934.51.76693128745.417.59.....4.91.....58.429...64.3184..91.657
A8: 9 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
B8: 2,7,5                                # reduction candidate for 2,7
B8: 2,7 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
B8: 5                                    # 21 pairs
* PAIR F9: 2,3 ROW 9
B9: 2,3,8                                # reduction candidate for 2,3
B9: 8                                    # 19 pairs
B9: 2,3                                  # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-455-base-pr-000.dot
* REASONING
* DIS # C7: 6,7 => CTR => C7: 1
* PRF # C7: 1 => SOL
* PRF # C8: 5,7 => SOL
* DIS # C8: 9 => CTR => C8: 5,7
* PRF # B9: 3 => SOL
* PRF # A7: 3,7 => SOL
* DIS # A7: 1 => CTR => A7: 3,7
* DIS # B7: 3,7 => CTR => B7: 6
* DIS # A8: 2,7 => CTR => A8: 9
* PRF # A8: 9 => SOL
* PRF # B8: 2,7 => SOL
* CNT  11 HDP CHAINS /  24 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B3,C1,C2,C3,C5,C6,C9,D1,D3,E5,E6,F7,F8,F9,G2,G3,H5,H6,I5,I6)
* ....9453151.376.94....51.76693128745...7.59.....4.91.....58.429...64.3184..91.657
* PAIR C1: 6,7 BLK 1
B1: 6,7,2,8                              # reduction candidate for 6,7
B1: 2,8                                  # 28 pairs
B1: 6,7                                  # 23 pairs
* PAIR C1: 6,7 COL C
C7: 6,7,1                                # reduction candidate for 6,7
C7: 6,7 => CTR
* ....9453151.376.9434..51.76693128745..17.59.....4.91..1..58.429...64.3184..91.657
C7: 1 => SOLVED
* 876294531512376894349851276693128745184735962257469183761583429925647318438912657
* DURATION: 0:00:05.867499  START: 18:19:04.824991  END: 18:19:10.692490 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-455-base-pr-001.dot
* REASONING
* DIS # C7: 6,7 => CTR => C7: 1
* PRF C7: 1 => SOL
* STA C7: 1
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 455

solution: 876294531512376894349851276693128745184735962257469183761583429925647318438912657
info: 95498    FNBTK    S8.f     6702

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

Solution

position: 876294531512376894349851276693128745184735962257469183761583429925647318438912657 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 # B1: 6,7 => UNS
* INC # B1: 2,8 => UNS
* DIS # C7: 6,7 => CTR => C7: 1
* PRF # C7: 1 => SOL
* INC # A1: 2,8 => UNS
* INC # B1: 2,8 => UNS
* INC # A1: 2,8 => UNS
* INC # B1: 2,8 => UNS
* INC # B6: 5,7 => UNS
* INC # B6: 2,8 => UNS
* PRF # C8: 5,7 => SOL
* DIS # C8: 9 => CTR => C8: 5,7
* INC # B9: 2,8 => UNS
* PRF # B9: 3 => SOL
* PRF # A7: 3,7 => SOL
* DIS # A7: 1 => CTR => A7: 3,7
* DIS # B7: 3,7 => CTR => B7: 6
* INC # B7: 6 => UNS
* DIS # A8: 2,7 => CTR => A8: 9
* PRF # A8: 9 => SOL
* PRF # B8: 2,7 => SOL
* INC # B8: 5 => UNS
* INC # B9: 2,3 => UNS
* INC # B9: 8 => UNS
* CNT  24 HDP CHAINS /  24 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B1: 6,7 => UNS
* INC # B1: 2,8 => UNS
* DIS # C7: 6,7 => CTR => C7: 1
* PRF C7: 1 => SOL
* STA C7: 1
* CNT   4 HDP CHAINS /   3 HYP OPENED