Analysis of xx-top500-267-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..36..2......9.8...7.......2..5..1......7..4......3...6..2......4.....7....1..... initial

Autosolve

position: 4.36182.7126795834.7.432.1.2.75..1.336..71.42.14.2376.6.12.7....423...717..1...2. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B7: 5,9 => CTR => B7: 3,8
* DIS # B9: 5,9 => CTR => B9: 3,8
* PRF # H7: 5,9 => SOL
* DIS # H7: 8 => CTR => H7: 5,9
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* PRF # B7: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 3,5
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # H7: 8,9 => CTR => H7: 5
* PRF # H7: 5 => SOL
* PRF # I6: 5,9 => SOL
* DIS # I6: 8 => CTR => I6: 5,9
* DIS # C5: 8 => CTR => C5: 5,9
* DIS # G8: 5 => CTR => G8: 6,9
* CNT  24 HDP CHAINS /  42 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 # B7: 5,9 => CTR => B7: 3,8
* DIS B7: 3,8 # B9: 5,9 => CTR => B9: 3,8
* PRF B7: 3,8 + B9: 3,8 => SOL
* STA B7: 3,8 + B9: 3,8
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

..36..2......9.8...7.......2..5..1......7..4......3...6..2......4.....7....1..... initial
4.36182.7126795834.7.432.1.2.75..1.336..71.42.14.2376.6.12.7....423...717..1...2. autosolve
453618297126795834978432516297564183365871942814923765681247359542389671739156428 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (12)
B1: 5,9
H1: 5,9
B4: 8,9
E4: 4,6
F4: 4,6
D5: 8,9
D6: 8,9
H4: 8,9
G5: 5,9
F8: 6,9
G7: 3,4
G9: 3,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B7,B9: 3.. / B7 = 3  => 12 pairs (_) / B9 = 3  => 11 pairs (_)
G7,G9: 3.. / G7 = 3  => 11 pairs (_) / G9 = 3  => 12 pairs (_)
B7,G7: 3.. / B7 = 3  => 12 pairs (_) / G7 = 3  => 11 pairs (_)
B9,G9: 3.. / B9 = 3  => 11 pairs (_) / G9 = 3  => 12 pairs (_)
E4,F4: 4.. / E4 = 4  => 10 pairs (_) / F4 = 4  => 12 pairs (_)
G7,G9: 4.. / G7 = 4  => 12 pairs (_) / G9 = 4  => 11 pairs (_)
E7,G7: 4.. / E7 = 4  => 11 pairs (_) / G7 = 4  => 12 pairs (_)
F4,F9: 4.. / F4 = 4  => 12 pairs (_) / F9 = 4  => 10 pairs (_)
C5,A6: 5.. / C5 = 5  =>  0 pairs (*) / A6 = 5  =>  0 pairs (X)
G5,I6: 5.. / G5 = 5  =>  0 pairs (X) / I6 = 5  =>  0 pairs (_)
B1,H1: 5.. / B1 = 5  =>  0 pairs (*) / H1 = 5  =>  0 pairs (X)
C5,G5: 5.. / C5 = 5  =>  0 pairs (*) / G5 = 5  =>  0 pairs (X)
A6,I6: 5.. / A6 = 5  =>  0 pairs (X) / I6 = 5  =>  0 pairs (_)
H1,H7: 5.. / H1 = 5  =>  0 pairs (X) / H7 = 5  =>  0 pairs (_)
G3,I3: 6.. / G3 = 6  => 16 pairs (_) / I3 = 6  => 15 pairs (_)
E4,F4: 6.. / E4 = 6  => 12 pairs (_) / F4 = 6  => 10 pairs (_)
G8,I9: 6.. / G8 = 6  => 15 pairs (_) / I9 = 6  => 16 pairs (_)
G3,G8: 6.. / G3 = 6  => 16 pairs (_) / G8 = 6  => 15 pairs (_)
I3,I9: 6.. / I3 = 6  => 15 pairs (_) / I9 = 6  => 16 pairs (_)
A3,C3: 8.. / A3 = 8  => 16 pairs (_) / C3 = 8  => 15 pairs (_)
D5,D6: 8.. / D5 = 8  => 13 pairs (_) / D6 = 8  =>  0 pairs (X)
H4,I6: 8.. / H4 = 8  =>  0 pairs (*) / I6 = 8  =>  0 pairs (X)
B4,H4: 8.. / B4 = 8  =>  0 pairs (X) / H4 = 8  =>  0 pairs (_)
C5,D5: 8.. / C5 = 8  =>  0 pairs (X) / D5 = 8  => 13 pairs (_)
A8,E8: 8.. / A8 = 8  =>  0 pairs (X) / E8 = 8  => 14 pairs (_)
H4,H7: 8.. / H4 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
D5,D6: 9.. / D5 = 9  =>  0 pairs (X) / D6 = 9  => 13 pairs (_)
F8,F9: 9.. / F8 = 9  => 14 pairs (_) / F9 = 9  => 14 pairs (_)
B1,H1: 9.. / B1 = 9  =>  0 pairs (X) / H1 = 9  =>  0 pairs (_)
B4,H4: 9.. / B4 = 9  =>  0 pairs (*) / H4 = 9  =>  0 pairs (X)
* DURATION: 0:00:59.217525  START: 12:00:12.032731  END: 12:01:11.250256 2017-05-04
* CP COUNT: (30)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B4,D5,D6,E4,F4,F8,G5,G7,G9,H1,H4)
* 4.36182.7126795834.7.432.1.2.75..1.336..71.42.14.2376.6.12.7....423...717..1...2.
* PAIR B1: 5,9 BLK 1
A3: 5,9,8                                # reduction candidate for 5,9
A3: 5,9                                  # 15 pairs
C3: 5,9,8                                # reduction candidate for 5,9
C3: 5,9                                  # 16 pairs
* PAIR B1: 5,9 COL B
B7: 5,9,3,8                              # reduction candidate for 5,9
B7: 5,9 => CTR
* 49361825712679583487.432.1.2875.419336.8715425149237686.124738..4235..7173.18.42.
B7: 3,8                                  # 14 pairs
B9: 5,9,3,8                              # reduction candidate for 5,9
B9: 5,9 => CTR
* 4.36182.7126795834.7.432.1.2875..19336.8715425149237686312.7489.4235..717..1..32.
B9: 3,8                                  # 13 pairs
* PAIR H1: 5,9 BLK 3
G3: 5,9,6                                # reduction candidate for 5,9
G3: 5,9                                  # 15 pairs
I3: 5,9,6                                # reduction candidate for 5,9
I3: 5,9                                  # 16 pairs
* PAIR H1: 5,9 COL H
H7: 5,9,8                                # reduction candidate for 5,9
H7: 5,9 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
H7: 8 => CTR
* 49361825712679583487.432.1.2.75..19336..715425149237686.12.7.8..4235..717..18..2.
* PAIR B4: 8,9 BLK 4
C5: 8,9,5                                # reduction candidate for 8,9
C5: 8,9 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
C5: 5 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
A6: 8,9,5                                # reduction candidate for 8,9
A6: 8,9 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
A6: 5 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
* PAIR B4: 8,9 COL B
B7: 8,9,3,5                              # reduction candidate for 8,9
B7: 8,9 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
B7: 3,5                                  # 14 pairs
B9: 8,9,3,5                              # reduction candidate for 8,9
B9: 8,9 => CTR
* 453618297126795834.7.432.1.2975..18336..71.42.14.2376.6312.7459.423..67178.1..32.
B9: 3,5                                  # 13 pairs
* PAIR E4: 4,6 COL E
E9: 4,6,5,8                              # reduction candidate for 4,6
E9: 4,6                                  # 14 pairs
E9: 5,8                                  # 13 pairs
* PAIR F4: 4,6 COL F
F9: 4,6,9                                # reduction candidate for 4,6
F9: 9                                    # 14 pairs
F9: 4,6                                  # 14 pairs
* PAIR D5: 8,9 ROW 5
C5: 8,9,5                                # reduction candidate for 8,9
C5: 8,9 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
C5: 5 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
* PAIR D6: 8,9 ROW 6
A6: 8,9,5                                # reduction candidate for 8,9
A6: 8,9 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
A6: 5 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
I6: 8,9,5                                # reduction candidate for 8,9
I6: 8,9 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
I6: 5 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
* PAIR H4: 8,9 BLK 6
I6: 8,9,5                                # reduction candidate for 8,9
I6: 8,9 => CTR
* 4.36182.71267958349784326152875..19336..71542514.2376.6.12.7...84235..717..1...2.
I6: 5 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
* PAIR H4: 8,9 COL H
H7: 8,9,5                                # reduction candidate for 8,9
H7: 8,9 => CTR
* 493618257126795834.7.432.1.2875..19336.8715425149237686.12.7.899423...717..1...2.
H7: 5 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
* PAIR G5: 5,9 BLK 6
I6: 5,9,8                                # reduction candidate for 5,9
I6: 5,9 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
I6: 8 => CTR
* 4.3618257126795834.75432.1.2875..1.336..715425149237686.12.7.8..4235..717..18..2.
* PAIR G5: 5,9 ROW 5
C5: 5,9,8                                # reduction candidate for 5,9
C5: 8 => CTR
* 4.36182.712679583487.432.1.2975..1833689715425148237696.12.7.9.942356.717..1...2.
C5: 5,9                                  # 13 pairs
* PAIR G5: 5,9 COL G
G3: 5,9,6                                # reduction candidate for 5,9
G3: 5,9                                  # 15 pairs
G8: 5,9,6                                # reduction candidate for 5,9
G8: 5,9                                  # 16 pairs
* PAIR F8: 6,9 BLK 8
F9: 6,9,4                                # reduction candidate for 6,9
F9: 6,9                                  # 12 pairs
F9: 4                                    # 10 pairs
* PAIR F8: 6,9 ROW 8
G8: 6,9,5                                # reduction candidate for 6,9
G8: 5 => CTR
* 4.36182571267958345784326192975..1.336..71942.149237656.12.7....423..5717..1...26
G8: 6,9                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-267-base-pr-000.dot
* REASONING
* DIS # B7: 5,9 => CTR => B7: 3,8
* DIS # B9: 5,9 => CTR => B9: 3,8
* PRF # H7: 5,9 => SOL
* DIS # H7: 8 => CTR => H7: 5,9
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* PRF # B7: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 3,5
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # H7: 8,9 => CTR => H7: 5
* PRF # H7: 5 => SOL
* PRF # I6: 5,9 => SOL
* DIS # I6: 8 => CTR => I6: 5,9
* DIS # C5: 8 => CTR => C5: 5,9
* DIS # G8: 5 => CTR => G8: 6,9
* CNT  24 HDP CHAINS /  42 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B4,D5,D6,E4,F4,F8,G5,G7,G9,H1,H4)
* 4.36182.7126795834.7.432.1.2.75..1.336..71.42.14.2376.6.12.7....423...717..1...2.
* PAIR B1: 5,9 BLK 1
A3: 5,9,8                                # reduction candidate for 5,9
A3: 5,9                                  # 15 pairs
C3: 5,9,8                                # reduction candidate for 5,9
C3: 5,9                                  # 16 pairs
* PAIR B1: 5,9 COL B
B7: 5,9,3,8                              # reduction candidate for 5,9
B7: 5,9 => CTR
* 49361825712679583487.432.1.2875.419336.8715425149237686.124738..4235..7173.18.42.
B9: 5,9,3,8                              # reduction candidate for 5,9
B9: 5,9 => CTR
* 4.36182.7126795834.7.432.1.2875..19336.8715425149237686312.7489.4235..717..1..32.
B9: 3,8 => SOLVED
* 453618297126795834978432516297564183365871942814923765681247359542389671739156428
* DURATION: 0:00:05.207242  START: 12:01:59.890644  END: 12:02:05.097886 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-267-base-pr-001.dot
* REASONING
* DIS # B7: 5,9 => CTR => B7: 3,8
* DIS B7: 3,8 # B9: 5,9 => CTR => B9: 3,8
* PRF B7: 3,8 + B9: 3,8 => SOL
* STA B7: 3,8 + B9: 3,8
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 267

solution: 453618297126795834978432516297564183365871942814923765681247359542389671739156428
info: 2139     FNBHWXY  S8.f     13530

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

Solution

position: 453618297126795834978432516297564183365871942814923765681247359542389671739156428 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 # A3: 5,9 => UNS
* INC # C3: 5,9 => UNS
* DIS # B7: 5,9 => CTR => B7: 3,8
* INC # B7: 3,8 => UNS
* DIS # B9: 5,9 => CTR => B9: 3,8
* INC # B9: 3,8 => UNS
* INC # G3: 5,9 => UNS
* INC # I3: 5,9 => UNS
* PRF # H7: 5,9 => SOL
* DIS # H7: 8 => CTR => H7: 5,9
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* PRF # B7: 8,9 => SOL
* INC # B7: 3,5 => UNS
* DIS # B9: 8,9 => CTR => B9: 3,5
* INC # B9: 3,5 => UNS
* INC # E9: 4,6 => UNS
* INC # E9: 5,8 => UNS
* INC # F9: 4,6 => UNS
* INC # F9: 9 => UNS
* DIS # C5: 8,9 => CTR => C5: 5
* PRF # C5: 5 => SOL
* PRF # A6: 8,9 => SOL
* DIS # A6: 5 => CTR => A6: 8,9
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # I6: 8,9 => CTR => I6: 5
* PRF # I6: 5 => SOL
* DIS # H7: 8,9 => CTR => H7: 5
* PRF # H7: 5 => SOL
* PRF # I6: 5,9 => SOL
* DIS # I6: 8 => CTR => I6: 5,9
* INC # C5: 5,9 => UNS
* DIS # C5: 8 => CTR => C5: 5,9
* INC # G3: 5,9 => UNS
* INC # G8: 5,9 => UNS
* INC # F9: 6,9 => UNS
* INC # F9: 4 => UNS
* INC # G8: 6,9 => UNS
* DIS # G8: 5 => CTR => G8: 6,9
* CNT  42 HDP CHAINS /  42 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 5,9 => UNS
* INC # C3: 5,9 => UNS
* DIS # B7: 5,9 => CTR => B7: 3,8
* DIS B7: 3,8 # B9: 5,9 => CTR => B9: 3,8
* PRF B7: 3,8 + B9: 3,8 => SOL
* STA B7: 3,8 + B9: 3,8
* CNT   5 HDP CHAINS /   4 HYP OPENED