Analysis of xx-top500-385-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .1...46......9...3..........2.8..7.....35....4..............21...35.....9.....4.. initial

Autosolve

position: 519.346.....19.5.3.3...59.1325841796.9.35.1.44.19..35..5.4.32191435298679.2.1.435 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D3: 6 => CTR => D3: 2,7
* PRF # E3: 6,7 => SOL
* PRF # F9: 6,7 => SOL
* PRF # B9: 8 => SOL
* CNT   4 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:

* DIS # D3: 6 => CTR => D3: 2,7
* DIS D3: 2,7 # H1: 2,7 => CTR => H1: 8
* PRF D3: 2,7 + H1: 8 # C2: 6,8 => SOL
* STA D3: 2,7 + H1: 8 + C2: 6,8
* CNT   3 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

.1...46......9...3..........2.8..7.....35....4..............21...35.....9.....4.. initial
519.346.....19.5.3.3...59.1325841796.9.35.1.44.19..35..5.4.32191435298679.2.1.435 autosolve
519734682276198543834265971325841796798356124461972358657483219143529867982617435 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (6)
D1: 2,7
I1: 2,8
E6: 6,7
H5: 2,8
I6: 2,8
D9: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,A3: 2.. / A2 = 2  =>  7 pairs (_) / A3 = 2  => 12 pairs (_)
D1,D3: 2.. / D1 = 2  => 14 pairs (_) / D3 = 2  => 12 pairs (_)
F5,F6: 2.. / F5 = 2  => 14 pairs (_) / F6 = 2  => 10 pairs (_)
H5,I6: 2.. / H5 = 2  => 10 pairs (_) / I6 = 2  => 14 pairs (_)
A2,H2: 2.. / A2 = 2  =>  7 pairs (_) / H2 = 2  => 12 pairs (_)
F5,H5: 2.. / F5 = 2  => 14 pairs (_) / H5 = 2  => 10 pairs (_)
F6,I6: 2.. / F6 = 2  => 10 pairs (_) / I6 = 2  => 14 pairs (_)
I1,I6: 2.. / I1 = 2  => 10 pairs (_) / I6 = 2  => 14 pairs (_)
C2,C3: 4.. / C2 = 4  =>  7 pairs (_) / C3 = 4  =>  7 pairs (_)
H2,H3: 4.. / H2 = 4  =>  7 pairs (_) / H3 = 4  =>  7 pairs (_)
C2,H2: 4.. / C2 = 4  =>  7 pairs (_) / H2 = 4  =>  7 pairs (_)
C3,H3: 4.. / C3 = 4  =>  7 pairs (_) / H3 = 4  =>  7 pairs (_)
D3,D9: 6.. / D3 = 6  =>  0 pairs (X) / D9 = 6  => 11 pairs (_)
D1,H1: 7.. / D1 = 7  => 12 pairs (_) / H1 = 7  => 14 pairs (_)
F2,E3: 8.. / F2 = 8  =>  0 pairs (*) / E3 = 8  =>  0 pairs (X)
H1,I1: 8.. / H1 = 8  => 10 pairs (_) / I1 = 8  => 14 pairs (_)
H5,I6: 8.. / H5 = 8  => 14 pairs (_) / I6 = 8  => 10 pairs (_)
E7,F9: 8.. / E7 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
B6,I6: 8.. / B6 = 8  => 14 pairs (_) / I6 = 8  => 10 pairs (_)
B9,F9: 8.. / B9 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
E3,E7: 8.. / E3 = 8  =>  9 pairs (_) / E7 = 8  =>  0 pairs (*)
F2,F9: 8.. / F2 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
H1,H5: 8.. / H1 = 8  => 10 pairs (_) / H5 = 8  => 14 pairs (_)
I1,I6: 8.. / I1 = 8  => 14 pairs (_) / I6 = 8  => 10 pairs (_)
* DURATION: 0:00:41.600000  START: 16:00:35.116133  END: 16:01:16.716133 2017-05-04
* CP COUNT: (24)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,D9,E6,H5,I1,I6)
* 519.346.....19.5.3.3...59.1325841796.9.35.1.44.19..35..5.4.32191435298679.2.1.435
* PAIR D1: 2,7 BLK 2
D3: 2,7,6                                # reduction candidate for 2,7
D3: 6 => CTR
* 519234678.7.19.5.3.3.6.59.1325841796.9.35.1844819..352.5.4.32191435298679.2718435
D3: 2,7                                  # 11 pairs
* PAIR D1: 2,7 ROW 1
H1: 2,7,8                                # reduction candidate for 2,7
H1: 2,7                                  # 14 pairs
H1: 8                                    # 10 pairs
* PAIR I1: 2,8 BLK 3
H1: 2,8,7                                # reduction candidate for 2,8
H1: 7                                    # 14 pairs
H1: 2,8                                  # 12 pairs
* PAIR E6: 6,7 BLK 5
F5: 6,7,2                                # reduction candidate for 6,7
F5: 6,7                                  # 10 pairs
F6: 6,7,2                                # reduction candidate for 6,7
F6: 6,7                                  # 14 pairs
* PAIR E6: 6,7 ROW 6
B6: 6,7,8                                # reduction candidate for 6,7
B6: 8                                    # 14 pairs
B6: 6,7                                  # 10 pairs
* PAIR E6: 6,7 COL E
E3: 6,7,8                                # reduction candidate for 6,7
E3: 6,7 => SOLVED
* 519734682276198543834265971325841796798356124461972358657483219143529867982617435
E3: 8                                    #  9 pairs
E7: 6,7,8                                # reduction candidate for 6,7
E7: 6,7                                  #  9 pairs
* PAIR H5: 2,8 COL H
H1: 2,8,7                                # reduction candidate for 2,8
H1: 7                                    # 14 pairs
H1: 2,8                                  # 12 pairs
* PAIR D9: 6,7 BLK 8
E7: 6,7,8                                # reduction candidate for 6,7
E7: 6,7                                  #  9 pairs
F9: 6,7,8                                # reduction candidate for 6,7
F9: 6,7 => SOLVED
* 519734682276198543834265971325841796798356124461972358657483219143529867982617435
F9: 8                                    #  9 pairs
* PAIR D9: 6,7 ROW 9
B9: 6,7,8                                # reduction candidate for 6,7
B9: 8 => SOLVED
* 519734682276198543834265971325841796798356124461972358657483219143529867982617435
B9: 6,7                                  #  9 pairs
* PAIR D9: 6,7 COL D
D3: 6,7,2                                # reduction candidate for 6,7
D3: 6,7                                  # 14 pairs
D3: 2                                    # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-385-base-pr-000.dot
* REASONING
* DIS # D3: 6 => CTR => D3: 2,7
* PRF # E3: 6,7 => SOL
* PRF # F9: 6,7 => SOL
* PRF # B9: 8 => SOL
* CNT   4 HDP CHAINS /  22 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,D9,E6,H5,I1,I6)
* 519.346.....19.5.3.3...59.1325841796.9.35.1.44.19..35..5.4.32191435298679.2.1.435
* PAIR D1: 2,7 BLK 2
D3: 2,7,6                                # reduction candidate for 2,7
D3: 6 => CTR
* 519234678.7.19.5.3.3.6.59.1325841796.9.35.1844819..352.5.4.32191435298679.2718435
* PAIR D1: 2,7 ROW 1
H1: 2,7,8                                # reduction candidate for 2,7
H1: 2,7 => CTR
* 519.346.8...19.5.3.3...59.1325841796.9.35.1844819..352.5.4.3219143529867972618435
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (B6,B9,E3,E6,E7,F2,F5,F9,H2,H3)
* 5197346822..19.5.3.3.2.59.1325841796.9.35.1244.19.2358.5.4.32191435298679.261.435
* PAIR F2: 6,8 ROW 2
B2: 6,8,7                                # reduction candidate for 6,8
B2: 6,8                                  # 12 pairs
C2: 6,8,4,7                              # reduction candidate for 6,8
C2: 6,8 => SOLVED
* 519734682276198543834265971325841796798356124461972358657483219143529867982617435
* DURATION: 0:00:07.359717  START: 16:01:39.375297  END: 16:01:46.735014 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-385-base-pr-001.dot
* REASONING
* DIS # D3: 6 => CTR => D3: 2,7
* DIS D3: 2,7 # H1: 2,7 => CTR => H1: 8
* PRF D3: 2,7 + H1: 8 # C2: 6,8 => SOL
* STA D3: 2,7 + H1: 8 + C2: 6,8
* CNT   3 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 385

solution: 519734682276198543834265971325841796798356124461972358657483219143529867982617435
info: 34331    FNBXYK   S8.f     15172

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

Solution

position: 519734682276198543834265971325841796798356124461972358657483219143529867982617435 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 # D3: 2,7 => UNS
* DIS # D3: 6 => CTR => D3: 2,7
* INC # H1: 2,7 => UNS
* INC # H1: 8 => UNS
* INC # H1: 2,8 => UNS
* INC # H1: 7 => UNS
* INC # F5: 6,7 => UNS
* INC # F6: 6,7 => UNS
* INC # B6: 6,7 => UNS
* INC # B6: 8 => UNS
* PRF # E3: 6,7 => SOL
* INC # E3: 8 => UNS
* INC # E7: 6,7 => UNS
* INC # H1: 2,8 => UNS
* INC # H1: 7 => UNS
* INC # E7: 6,7 => UNS
* PRF # F9: 6,7 => SOL
* INC # F9: 8 => UNS
* INC # B9: 6,7 => UNS
* PRF # B9: 8 => SOL
* INC # D3: 6,7 => UNS
* INC # D3: 2 => UNS
* CNT  22 HDP CHAINS /  22 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D3: 2,7 => UNS
* DIS # D3: 6 => CTR => D3: 2,7
* DIS D3: 2,7 # H1: 2,7 => CTR => H1: 8
* INC D3: 2,7 + H1: 8 # B2: 6,8 => UNS
* PRF D3: 2,7 + H1: 8 # C2: 6,8 => SOL
* STA D3: 2,7 + H1: 8 + C2: 6,8
* CNT   5 HDP CHAINS /   5 HYP OPENED