Analysis of xx-top500-434-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ......8.1...6........5........4...5..9.....4..2..7....3...1.7..5.....1..4.6...... initial

Autosolve

position: 657.4.8.1.4.6..5...3.5..4.61634.8.577951...48824.7561.38..1476557.8..1.441675..8. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS # H2: 2,9 => CTR => H2: 3,7
* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS # E8: 2,9 => CTR => E8: 3,6
* PRF # D1: 2 => SOL
* PRF # I9: 3,9 => SOL
* DIS # E8: 2,9 => CTR => E8: 3,6
* DIS # F8: 2,9 => CTR => F8: 3,6
* DIS # E8: 2,9 => CTR => E8: 3,6
* DIS # F8: 2,9 => CTR => F8: 3,6
* DIS # D1: 3 => CTR => D1: 2,9
* PRF # I9: 3,9 => SOL
* PRF # F9: 2 => SOL
* CNT  13 HDP CHAINS /  36 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 # E2: 2,9 => CTR => E2: 3,8
* DIS E2: 3,8 # H2: 2,9 => CTR => H2: 3,7
* PRF E2: 3,8 + H2: 3,7 # H3: 2,9 => SOL
* STA E2: 3,8 + H2: 3,7 + H3: 2,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

......8.1...6........5........4...5..9.....4..2..7....3...1.7..5.....1..4.6...... initial
657.4.8.1.4.6..5...3.5..4.61634.8.577951...48824.7561.38..1476557.8..1.441675..8. autosolve
657249831948631572231587496163498257795126348824375619382914765579863124416752983 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
A2: 2,9
C2: 1,8
A3: 2,9
C3: 1,8
F2: 1,7
F3: 1,7
E4: 2,9
D6: 3,9
G4: 2,9
G5: 2,3
I6: 3,9
C7: 2,9
C8: 2,9
D7: 2,9
G9: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C2,C3: 1.. / C2 = 1  => 15 pairs (_) / C3 = 1  => 12 pairs (_)
F2,F3: 1.. / F2 = 1  => 12 pairs (_) / F3 = 1  => 15 pairs (_)
C2,F2: 1.. / C2 = 1  => 15 pairs (_) / F2 = 1  => 12 pairs (_)
C3,F3: 1.. / C3 = 1  => 12 pairs (_) / F3 = 1  => 15 pairs (_)
A2,A3: 2.. / A2 = 2  => 18 pairs (_) / A3 = 2  => 18 pairs (_)
G4,G5: 2.. / G4 = 2  => 20 pairs (_) / G5 = 2  =>  0 pairs (X)
C7,C8: 2.. / C7 = 2  =>  0 pairs (*) / C8 = 2  =>  0 pairs (X)
H8,I9: 2.. / H8 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
E4,G4: 2.. / E4 = 2  =>  0 pairs (X) / G4 = 2  => 20 pairs (_)
C7,D7: 2.. / C7 = 2  =>  0 pairs (*) / D7 = 2  =>  0 pairs (X)
F9,I9: 2.. / F9 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
D1,D7: 2.. / D1 = 2  =>  0 pairs (*) / D7 = 2  =>  0 pairs (X)
I2,I9: 2.. / I2 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
G5,I6: 3.. / G5 = 3  => 20 pairs (_) / I6 = 3  =>  0 pairs (X)
D6,I6: 3.. / D6 = 3  => 20 pairs (_) / I6 = 3  =>  0 pairs (X)
D1,D6: 3.. / D1 = 3  =>  0 pairs (X) / D6 = 3  => 20 pairs (_)
G5,G9: 3.. / G5 = 3  => 20 pairs (_) / G9 = 3  =>  0 pairs (X)
E5,F5: 6.. / E5 = 6  => 16 pairs (_) / F5 = 6  => 19 pairs (_)
E8,F8: 6.. / E8 = 6  => 19 pairs (_) / F8 = 6  => 16 pairs (_)
E5,E8: 6.. / E5 = 6  => 16 pairs (_) / E8 = 6  => 19 pairs (_)
F5,F8: 6.. / F5 = 6  => 19 pairs (_) / F8 = 6  => 16 pairs (_)
F2,F3: 7.. / F2 = 7  => 15 pairs (_) / F3 = 7  => 12 pairs (_)
H2,H3: 7.. / H2 = 7  => 12 pairs (_) / H3 = 7  => 15 pairs (_)
F2,H2: 7.. / F2 = 7  => 15 pairs (_) / H2 = 7  => 12 pairs (_)
F3,H3: 7.. / F3 = 7  => 12 pairs (_) / H3 = 7  => 15 pairs (_)
C2,C3: 8.. / C2 = 8  => 12 pairs (_) / C3 = 8  => 15 pairs (_)
E2,E3: 8.. / E2 = 8  => 15 pairs (_) / E3 = 8  => 12 pairs (_)
C2,E2: 8.. / C2 = 8  => 12 pairs (_) / E2 = 8  => 15 pairs (_)
C3,E3: 8.. / C3 = 8  => 15 pairs (_) / E3 = 8  => 12 pairs (_)
A2,A3: 9.. / A2 = 9  => 18 pairs (_) / A3 = 9  => 18 pairs (_)
E4,D6: 9.. / E4 = 9  => 20 pairs (_) / D6 = 9  =>  0 pairs (X)
G4,I6: 9.. / G4 = 9  =>  0 pairs (X) / I6 = 9  => 20 pairs (_)
C7,C8: 9.. / C7 = 9  => 16 pairs (_) / C8 = 9  =>  0 pairs (*)
E4,G4: 9.. / E4 = 9  => 20 pairs (_) / G4 = 9  =>  0 pairs (X)
D6,I6: 9.. / D6 = 9  =>  0 pairs (X) / I6 = 9  => 20 pairs (_)
C7,D7: 9.. / C7 = 9  => 16 pairs (_) / D7 = 9  =>  0 pairs (*)
G4,G9: 9.. / G4 = 9  =>  0 pairs (X) / G9 = 9  => 20 pairs (_)
* DURATION: 0:01:15.709411  START: 17:35:05.888015  END: 17:36:21.597426 2017-05-04
* CP COUNT: (37)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,C2,C3,C7,C8,D6,D7,E4,F2,F3,G4,G5,G9,I6)
* 657.4.8.1.4.6..5...3.5..4.61634.8.577951...48824.7561.38..1476557.8..1.441675..8.
* PAIR A2: 2,9 ROW 2
E2: 2,9,3,8                              # reduction candidate for 2,9
E2: 2,9 => CTR
* 657.4.8.1.486.1573.315874.61634.8.577951..34882437561938..1476557.8361.441675.982
E2: 3,8                                  # 16 pairs
H2: 2,9,3,7                              # reduction candidate for 2,9
H2: 2,9 => CTR
* 657.4.8.1.416875.3.385.14761634.8.577951..34882437561938..1476557.8361.441675.982
H2: 3,7                                  # 16 pairs
I2: 2,9,3                                # reduction candidate for 2,9
I2: 2,9                                  # 22 pairs
* PAIR A3: 2,9 ROW 3
E3: 2,9,8                                # reduction candidate for 2,9
E3: 2,9                                  # 15 pairs
H3: 2,9,7                                # reduction candidate for 2,9
H3: 2,9                                  # 12 pairs
* PAIR E4: 2,9 COL E
E2: 2,9,3,8                              # reduction candidate for 2,9
E2: 2,9 => CTR
* 657.4.8.1.486.1573.315874.61634.8.577951..34882437561938..1476557.8361.441675.982
E2: 3,8                                  # 16 pairs
E3: 2,9,8                                # reduction candidate for 2,9
E3: 2,9                                  # 15 pairs
E8: 2,9,3,6                              # reduction candidate for 2,9
E8: 2,9 => CTR
* 657349821.4.6..5.3.3.5..4.61634.8.5779516..48824.7561.38..1476557.8.6134416753982
E8: 3,6                                  # 16 pairs
* PAIR D6: 3,9 COL D
D1: 3,9,2                                # reduction candidate for 3,9
D1: 2 => SOLVED
* 657249831948631572231587496163498257795126348824375619382914765579863124416752983
D1: 3,9                                  # 16 pairs
* PAIR G5: 2,3 ROW 5
E5: 2,3,6                                # reduction candidate for 2,3
E5: 2,3                                  # 19 pairs
F5: 2,3,6                                # reduction candidate for 2,3
F5: 2,3                                  # 16 pairs
* PAIR I6: 3,9 COL I
I2: 3,9,2                                # reduction candidate for 3,9
I2: 3,9                                  # 18 pairs
I9: 3,9,2                                # reduction candidate for 3,9
I9: 3,9 => SOLVED
* 657249831948631572231587496163498257795126348824375619382914765579863124416752983
I9: 2                                    # 18 pairs
* PAIR C8: 2,9 ROW 8
E8: 2,9,3,6                              # reduction candidate for 2,9
E8: 2,9 => CTR
* 657349821.4.6..5.3.3.5..4.61634.8.5779516..48824.7561.38..1476557.8.6134416753982
E8: 3,6                                  # 16 pairs
F8: 2,9,3,6                              # reduction candidate for 2,9
F8: 2,9 => CTR
* 65734.8.1.4.6..5.3.3.5..4.61634.8.577951.6.48824.7561.38..1476557.86.134416753982
F8: 3,6                                  # 16 pairs
H8: 2,9,3                                # reduction candidate for 2,9
H8: 2,9                                  # 22 pairs
* PAIR D7: 2,9 BLK 8
E8: 2,9,3,6                              # reduction candidate for 2,9
E8: 2,9 => CTR
* 657349821.4.6..5.3.3.5..4.61634.8.5779516..48824.7561.38..1476557.8.6134416753982
E8: 3,6                                  # 16 pairs
F8: 2,9,3,6                              # reduction candidate for 2,9
F8: 2,9 => CTR
* 65734.8.1.4.6..5.3.3.5..4.61634.8.577951.6.48824.7561.38..1476557.86.134416753982
F8: 3,6                                  # 16 pairs
F9: 2,9,3                                # reduction candidate for 2,9
F9: 2,9                                  # 22 pairs
* PAIR D7: 2,9 COL D
D1: 2,9,3                                # reduction candidate for 2,9
D1: 3 => CTR
* 65734.8.1.4.6..53993.5..4761634289577951..24882497561338921476557289.1.441675.382
D1: 2,9                                  # 20 pairs
* PAIR G9: 3,9 BLK 9
H8: 3,9,2                                # reduction candidate for 3,9
H8: 3,9                                  # 18 pairs
I9: 3,9,2                                # reduction candidate for 3,9
I9: 3,9 => SOLVED
* 657249831948631572231587496163498257795126348824375619382914765579863124416752983
I9: 2                                    # 18 pairs
* PAIR G9: 3,9 ROW 9
F9: 3,9,2                                # reduction candidate for 3,9
F9: 2 => SOLVED
* 657249831948631572231587496163498257795126348824375619382914765579863124416752983
F9: 3,9                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-434-base-pr-000.dot
* REASONING
* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS # H2: 2,9 => CTR => H2: 3,7
* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS # E8: 2,9 => CTR => E8: 3,6
* PRF # D1: 2 => SOL
* PRF # I9: 3,9 => SOL
* DIS # E8: 2,9 => CTR => E8: 3,6
* DIS # F8: 2,9 => CTR => F8: 3,6
* DIS # E8: 2,9 => CTR => E8: 3,6
* DIS # F8: 2,9 => CTR => F8: 3,6
* DIS # D1: 3 => CTR => D1: 2,9
* PRF # I9: 3,9 => SOL
* PRF # F9: 2 => SOL
* CNT  13 HDP CHAINS /  36 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,C2,C3,C7,C8,D6,D7,E4,F2,F3,G4,G5,G9,I6)
* 657.4.8.1.4.6..5...3.5..4.61634.8.577951...48824.7561.38..1476557.8..1.441675..8.
* PAIR A2: 2,9 ROW 2
E2: 2,9,3,8                              # reduction candidate for 2,9
E2: 2,9 => CTR
* 657.4.8.1.486.1573.315874.61634.8.577951..34882437561938..1476557.8361.441675.982
H2: 2,9,3,7                              # reduction candidate for 2,9
H2: 2,9 => CTR
* 657.4.8.1.416875.3.385.14761634.8.577951..34882437561938..1476557.8361.441675.982
* RESTART
* PAIR RESTART
* PAIR A3: 2,9 ROW 3
E3: 2,9,8                                # reduction candidate for 2,9
E3: 2,9                                  # 19 pairs
H3: 2,9,7                                # reduction candidate for 2,9
H3: 2,9 => SOLVED
* 657249831948631572231587496163498257795126348824375619382914765579863124416752983
* DURATION: 0:00:06.458833  START: 17:37:01.933241  END: 17:37:08.392074 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-434-base-pr-001.dot
* REASONING
* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS E2: 3,8 # H2: 2,9 => CTR => H2: 3,7
* PRF E2: 3,8 + H2: 3,7 # H3: 2,9 => SOL
* STA E2: 3,8 + H2: 3,7 + H3: 2,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 434

solution: 657249831948631572231587496163498257795126348824375619382914765579863124416752983
info: 95230    FNBTHWXK S8.f     1619

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

Solution

position: 657249831948631572231587496163498257795126348824375619382914765579863124416752983 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 # E2: 2,9 => CTR => E2: 3,8
* INC # E2: 3,8 => UNS
* DIS # H2: 2,9 => CTR => H2: 3,7
* INC # H2: 3,7 => UNS
* INC # I2: 2,9 => UNS
* INC # E3: 2,9 => UNS
* INC # H3: 2,9 => UNS
* DIS # E2: 2,9 => CTR => E2: 3,8
* INC # E2: 3,8 => UNS
* INC # E3: 2,9 => UNS
* DIS # E8: 2,9 => CTR => E8: 3,6
* INC # E8: 3,6 => UNS
* INC # D1: 3,9 => UNS
* PRF # D1: 2 => SOL
* INC # E5: 2,3 => UNS
* INC # F5: 2,3 => UNS
* INC # I2: 3,9 => UNS
* PRF # I9: 3,9 => SOL
* INC # I9: 2 => UNS
* DIS # E8: 2,9 => CTR => E8: 3,6
* INC # E8: 3,6 => UNS
* DIS # F8: 2,9 => CTR => F8: 3,6
* INC # F8: 3,6 => UNS
* INC # H8: 2,9 => UNS
* DIS # E8: 2,9 => CTR => E8: 3,6
* INC # E8: 3,6 => UNS
* DIS # F8: 2,9 => CTR => F8: 3,6
* INC # F8: 3,6 => UNS
* INC # F9: 2,9 => UNS
* INC # D1: 2,9 => UNS
* DIS # D1: 3 => CTR => D1: 2,9
* INC # H8: 3,9 => UNS
* PRF # I9: 3,9 => SOL
* INC # I9: 2 => UNS
* INC # F9: 3,9 => UNS
* PRF # F9: 2 => SOL
* CNT  36 HDP CHAINS /  36 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # E2: 2,9 => CTR => E2: 3,8
* DIS E2: 3,8 # H2: 2,9 => CTR => H2: 3,7
* INC E2: 3,8 + H2: 3,7 # E3: 2,9 => UNS
* PRF E2: 3,8 + H2: 3,7 # H3: 2,9 => SOL
* STA E2: 3,8 + H2: 3,7 + H3: 2,9
* CNT   4 HDP CHAINS /   4 HYP OPENED