Analysis of xx-top500-037-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...2..6..3.4.......1......82.....7......8..4......1......76.5...6.3............1. initial

Autosolve

position: ...2486313841.6...612...4.82416..78...6.8.14.8..4.1.6.1.876.5...6.31.8.....8...16 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E3: 5,9 => CTR => E3: 3,7
* DIS # F3: 5,9 => CTR => F3: 3,7
* DIS # H3: 7 => CTR => H3: 5,9
* DIS # I2: 2,9 => CTR => I2: 7
* DIS # G6: 2,9 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* PRF # F4: 5,9 => SOL
* DIS # B5: 5,9 => CTR => B5: 3,7
* DIS # I5: 5,9 => CTR => I5: 2,3
* DIS # I5: 5,9 => CTR => I5: 2,3
* PRF # F4: 5,9 => SOL
* DIS # A9: 5,9 => CTR => A9: 4,7
* DIS # B9: 5,9 => CTR => B9: 2,3,7
* DIS # C9: 5,9 => CTR => C9: 3,7
* DIS # F8: 5,9 => CTR => F8: 2,4
* DIS # C6: 5,9 => CTR => C6: 3,7
* DIS # I7: 2,9 => CTR => I7: 3,4
* DIS # H8: 2,9 => CTR => H8: 7
* DIS # I8: 2,9 => CTR => I8: 4,7
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* PRF # B7: 2,9 => SOL
* DIS # B7: 3 => CTR => B7: 2,9
* DIS # F7: 2,9 => CTR => F7: 4
* PRF # F7: 4 => SOL
* CNT  27 HDP CHAINS /  54 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 # E3: 5,9 => CTR => E3: 3,7
* DIS E3: 3,7 # F3: 5,9 => CTR => F3: 3,7
* DIS E3: 3,7 + F3: 3,7 # I2: 2,9 => CTR => I2: 7
* DIS E3: 3,7 + F3: 3,7 + I2: 7 # H2: 5 => CTR => H2: 2,9
* DIS E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 # G6: 2,9 => CTR => G6: 3
* PRF E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3 => SOL
* STA E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3
* CNT   6 HDP CHAINS /   8 HYP OPENED

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

Details

Positions

...2..6..3.4.......1......82.....7......8..4......1......76.5...6.3............1. initial
...2486313841.6...612...4.82416..78...6.8.14.8..4.1.6.1.876.5...6.31.8.....8...16 autosolve
795248631384156927612973458241639785936587142857421369128764593569312874473895216 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
D3: 5,9
G2: 2,9
D5: 5,9
F5: 2,7
E6: 2,7
I4: 5,9
C8: 5,9
H7: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F5,E6: 2.. / F5 = 2  =>  0 pairs (X) / E6 = 2  =>  0 pairs (_)
B7,B9: 2.. / B7 = 2  =>  0 pairs (*) / B9 = 2  =>  0 pairs (X)
F5,I5: 2.. / F5 = 2  =>  0 pairs (X) / I5 = 2  =>  0 pairs (_)
E6,E9: 2.. / E6 = 2  =>  0 pairs (*) / E9 = 2  =>  0 pairs (X)
E3,F3: 3.. / E3 = 3  =>  9 pairs (_) / F3 = 3  =>  0 pairs (*)
E4,F4: 3.. / E4 = 3  =>  0 pairs (*) / F4 = 3  =>  0 pairs (X)
I7,G9: 3.. / I7 = 3  =>  0 pairs (*) / G9 = 3  =>  0 pairs (X)
B5,I5: 3.. / B5 = 3  =>  0 pairs (*) / I5 = 3  =>  0 pairs (X)
B7,I7: 3.. / B7 = 3  =>  0 pairs (X) / I7 = 3  =>  0 pairs (_)
C6,C9: 3.. / C6 = 3  =>  0 pairs (X) / C9 = 3  =>  0 pairs (_)
E3,E4: 3.. / E3 = 3  =>  9 pairs (_) / E4 = 3  =>  0 pairs (*)
F3,F4: 3.. / F3 = 3  =>  0 pairs (*) / F4 = 3  =>  0 pairs (X)
G6,G9: 3.. / G6 = 3  =>  0 pairs (*) / G9 = 3  =>  0 pairs (X)
A8,A9: 4.. / A8 = 4  =>  0 pairs (X) / A9 = 4  => 13 pairs (_)
I7,I8: 4.. / I7 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
F7,I7: 4.. / F7 = 4  =>  0 pairs (*) / I7 = 4  =>  0 pairs (X)
A9,F9: 4.. / A9 = 4  => 13 pairs (_) / F9 = 4  =>  0 pairs (X)
H2,H3: 5.. / H2 = 5  => 11 pairs (_) / H3 = 5  => 11 pairs (_)
E2,H2: 5.. / E2 = 5  => 11 pairs (_) / H2 = 5  => 11 pairs (_)
D3,D5: 5.. / D3 = 5  => 15 pairs (_) / D5 = 5  => 10 pairs (_)
F5,E6: 7.. / F5 = 7  =>  0 pairs (*) / E6 = 7  =>  0 pairs (X)
H8,I8: 7.. / H8 = 7  => 12 pairs (_) / I8 = 7  =>  0 pairs (X)
F3,F5: 7.. / F3 = 7  =>  0 pairs (X) / F5 = 7  =>  0 pairs (_)
I2,I8: 7.. / I2 = 7  => 12 pairs (_) / I8 = 7  =>  0 pairs (X)
D3,D5: 9.. / D3 = 9  => 10 pairs (_) / D5 = 9  => 15 pairs (_)
* DURATION: 0:00:41.616835  START: 03:56:07.548075  END: 03:56:49.164910 2017-05-04
* CP COUNT: (25)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C8,D3,D5,E6,F5,G2,H7,I4)
* ...2486313841.6...612...4.82416..78...6.8.14.8..4.1.6.1.876.5...6.31.8.....8...16
* PAIR D3: 5,9 BLK 2
E2: 5,9,7                                # reduction candidate for 5,9
E2: 5,9                                  # 12 pairs
E3: 5,9,3,7                              # reduction candidate for 5,9
E3: 5,9 => CTR
* ...248631384176.59612..3478241639785.365871428..4219631.876.5...6.31.8.7...8...16
E3: 3,7                                  #  9 pairs
F3: 5,9,3,7                              # reduction candidate for 5,9
F3: 5,9 => CTR
* ...248631384176.59612.3.478241693785.365871428..4219631.876.5...6.31.8.7...8...16
F3: 3,7                                  #  9 pairs
* PAIR D3: 5,9 ROW 3
H3: 5,9,7                                # reduction candidate for 5,9
H3: 7 => CTR
* ...248631384176259612...4782416..785.365871428..4219631.876.5...6.31.8.7...8...16
H3: 5,9                                  # 12 pairs
* PAIR G2: 2,9 BLK 3
H2: 2,9,5,7                              # reduction candidate for 2,9
H2: 2,9                                  # 12 pairs
I2: 2,9,7                                # reduction candidate for 2,9
I2: 2,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5.4.6.31.8.7.2.8..316
I2: 7                                    # 12 pairs
* PAIR G2: 2,9 COL G
G6: 2,9,3                                # reduction candidate for 2,9
G6: 2,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5...6.31.8...2.8..316
G6: 3 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
G9: 2,9,3                                # reduction candidate for 2,9
G9: 2,9 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
G9: 3 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5...6.31.8...2.8..316
* PAIR D5: 5,9 BLK 5
E4: 5,9,3                                # reduction candidate for 5,9
E4: 5,9                                  #  9 pairs
F4: 5,9,3                                # reduction candidate for 5,9
F4: 5,9 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
F4: 3                                    #  9 pairs
* PAIR D5: 5,9 ROW 5
A5: 5,9,7                                # reduction candidate for 5,9
A5: 5,9                                  # 11 pairs
B5: 5,9,3,7                              # reduction candidate for 5,9
B5: 5,9 => CTR
* ...2486313841.6...612...4.82416..78...6.821438.3471.6.13876.5...6.31.8...2.8..316
B5: 3,7                                  #  9 pairs
I5: 5,9,2,3                              # reduction candidate for 5,9
I5: 5,9 => CTR
* ...2486313841.6...612...4.82416..78..36.8214.8..471.6.1.876.5.3.6.31.8.44.382.916
I5: 2,3                                  #  9 pairs
* PAIR I4: 5,9 BLK 6
I5: 5,9,2,3                              # reduction candidate for 5,9
I5: 5,9 => CTR
* ...2486313841.6...612...4.82416..78..36.8214.8..471.6.1.876.5.3.6.31.8.44.382.916
I5: 2,3                                  #  9 pairs
I6: 5,9,2,3                              # reduction candidate for 5,9
I6: 5,9                                  # 12 pairs
* PAIR I4: 5,9 ROW 4
E4: 5,9,3                                # reduction candidate for 5,9
E4: 5,9                                  #  9 pairs
F4: 5,9,3                                # reduction candidate for 5,9
F4: 5,9 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
F4: 3                                    #  9 pairs
* PAIR C8: 5,9 BLK 7
A8: 5,9,4                                # reduction candidate for 5,9
A8: 5,9                                  # 13 pairs
A9: 5,9,4,7                              # reduction candidate for 5,9
A9: 5,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5.446.31.8...278.4316
A9: 4,7                                  #  9 pairs
B9: 5,9,2,3,7                            # reduction candidate for 5,9
B9: 5,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.14.8..4.1.6.12876.593.6.31.8.44..8...16
B9: 2,3,7                                #  8 pairs
C9: 5,9,3,7                              # reduction candidate for 5,9
C9: 5,9 => CTR
* ..72486313841.6...612...4.82416..78...6.821438.3471.6.13876.5...6.31.8..72.8.4316
C9: 3,7                                  #  9 pairs
* PAIR C8: 5,9 ROW 8
F8: 5,9,2,4                              # reduction candidate for 5,9
F8: 5,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.14.8.34.1.6.138762594.6.31.8.....8..316
F8: 2,4                                  #  9 pairs
* PAIR C8: 5,9 COL C
C1: 5,9,7                                # reduction candidate for 5,9
C1: 5,9                                  # 11 pairs
C6: 5,9,3,7                              # reduction candidate for 5,9
C6: 5,9 => CTR
* ..72486313841.6..7612...4.82416..78.736.8214.8..471362128764593.6.31.8.44738...16
C6: 3,7                                  #  9 pairs
* PAIR H7: 2,9 BLK 9
I7: 2,9,3,4                              # reduction candidate for 2,9
I7: 2,9 => CTR
* ...2486313841.6..7612...4.82416..78...6.8.1438.34219651387645...6.31.8.44278..316
I7: 3,4                                  #  9 pairs
H8: 2,9,7                                # reduction candidate for 2,9
H8: 2,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5.4.6.31.8.7.2.8..316
H8: 7                                    # 12 pairs
I8: 2,9,4,7                              # reduction candidate for 2,9
I8: 2,9 => CTR
* ...2486313841.6..7612...4.82416..78...6.8.1438.342196513876.5.4.6.31.87..2.8..316
I8: 4,7                                  #  9 pairs
G9: 2,9,3                                # reduction candidate for 2,9
G9: 2,9 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
G9: 3 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5...6.31.8...2.8..316
* PAIR H7: 2,9 ROW 7
B7: 2,9,3                                # reduction candidate for 2,9
B7: 2,9 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
B7: 3 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5...6.31.8...2.8..316
F7: 2,9,4                                # reduction candidate for 2,9
F7: 2,9 => CTR
* ...2486313841.6...612...4.82416..78...6.8.1438.342196513876.5.4.6.31.8...2.8..316
F7: 4 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
* PAIR H7: 2,9 COL H
H2: 2,9,5,7                              # reduction candidate for 2,9
H2: 2,9                                  # 12 pairs
H2: 5,7                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-037-base-pr-000.dot
* REASONING
* DIS # E3: 5,9 => CTR => E3: 3,7
* DIS # F3: 5,9 => CTR => F3: 3,7
* DIS # H3: 7 => CTR => H3: 5,9
* DIS # I2: 2,9 => CTR => I2: 7
* DIS # G6: 2,9 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* PRF # F4: 5,9 => SOL
* DIS # B5: 5,9 => CTR => B5: 3,7
* DIS # I5: 5,9 => CTR => I5: 2,3
* DIS # I5: 5,9 => CTR => I5: 2,3
* PRF # F4: 5,9 => SOL
* DIS # A9: 5,9 => CTR => A9: 4,7
* DIS # B9: 5,9 => CTR => B9: 2,3,7
* DIS # C9: 5,9 => CTR => C9: 3,7
* DIS # F8: 5,9 => CTR => F8: 2,4
* DIS # C6: 5,9 => CTR => C6: 3,7
* DIS # I7: 2,9 => CTR => I7: 3,4
* DIS # H8: 2,9 => CTR => H8: 7
* DIS # I8: 2,9 => CTR => I8: 4,7
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* PRF # B7: 2,9 => SOL
* DIS # B7: 3 => CTR => B7: 2,9
* DIS # F7: 2,9 => CTR => F7: 4
* PRF # F7: 4 => SOL
* CNT  27 HDP CHAINS /  54 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C8,D3,D5,E6,F5,G2,H7,I4)
* ...2486313841.6...612...4.82416..78...6.8.14.8..4.1.6.1.876.5...6.31.8.....8...16
* PAIR D3: 5,9 BLK 2
E2: 5,9,7                                # reduction candidate for 5,9
E2: 5,9                                  # 12 pairs
E3: 5,9,3,7                              # reduction candidate for 5,9
E3: 5,9 => CTR
* ...248631384176.59612..3478241639785.365871428..4219631.876.5...6.31.8.7...8...16
F3: 5,9,3,7                              # reduction candidate for 5,9
F3: 5,9 => CTR
* ...248631384176.59612.3.478241693785.365871428..4219631.876.5...6.31.8.7...8...16
* RESTART
* PAIR G2: 2,9 BLK 3
H2: 2,9,5,7                              # reduction candidate for 2,9
H2: 2,9                                  # 12 pairs
I2: 2,9,7                                # reduction candidate for 2,9
I2: 2,9 => CTR
* ...248631384156.7.6129..458241639785..658.1438534.1.6.13876.5.4.6.31.8.7.2.89.316
* RESTART
* PAIR G2: 2,9 BLK 3
H2: 2,9,5                                # reduction candidate for 2,9
H2: 5 => CTR
* ...2486313841962576125..4982416..789..69871428..4213651.876.523.6.31287442.8...16
* PAIR G2: 2,9 COL G
G6: 2,9,3                                # reduction candidate for 2,9
G6: 2,9 => CTR
* ...248631384156..76129..458241639785..658.1438534.1.6.13876.5...6.31.87..2.89.316
G6: 3 => SOLVED
* 795248631384156927612973458241639785936587142857421369128764593569312874473895216
* DURATION: 0:00:09.110727  START: 03:57:37.419951  END: 03:57:46.530678 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-037-base-pr-001.dot
* REASONING
* DIS # E3: 5,9 => CTR => E3: 3,7
* DIS E3: 3,7 # F3: 5,9 => CTR => F3: 3,7
* DIS E3: 3,7 + F3: 3,7 # I2: 2,9 => CTR => I2: 7
* DIS E3: 3,7 + F3: 3,7 + I2: 7 # H2: 5 => CTR => H2: 2,9
* DIS E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 # G6: 2,9 => CTR => G6: 3
* PRF E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3 => SOL
* STA E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3
* CNT   6 HDP CHAINS /   8 HYP OPENED

Header Info

Top 500 Minimum 17 037

solution: 795248631384156927612973458241639785936587142857421369128764593569312874473895216
info: 1368     FNBHWXY  S8.f     7698

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

Solution

position: 795248631384156927612973458241639785936587142857421369128764593569312874473895216 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 # E2: 5,9 => UNS
* DIS # E3: 5,9 => CTR => E3: 3,7
* INC # E3: 3,7 => UNS
* DIS # F3: 5,9 => CTR => F3: 3,7
* INC # F3: 3,7 => UNS
* INC # H3: 5,9 => UNS
* DIS # H3: 7 => CTR => H3: 5,9
* INC # H2: 2,9 => UNS
* DIS # I2: 2,9 => CTR => I2: 7
* INC # I2: 7 => UNS
* DIS # G6: 2,9 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* INC # E4: 5,9 => UNS
* PRF # F4: 5,9 => SOL
* INC # F4: 3 => UNS
* INC # A5: 5,9 => UNS
* DIS # B5: 5,9 => CTR => B5: 3,7
* INC # B5: 3,7 => UNS
* DIS # I5: 5,9 => CTR => I5: 2,3
* INC # I5: 2,3 => UNS
* DIS # I5: 5,9 => CTR => I5: 2,3
* INC # I5: 2,3 => UNS
* INC # I6: 5,9 => UNS
* INC # E4: 5,9 => UNS
* PRF # F4: 5,9 => SOL
* INC # F4: 3 => UNS
* INC # A8: 5,9 => UNS
* DIS # A9: 5,9 => CTR => A9: 4,7
* INC # A9: 4,7 => UNS
* DIS # B9: 5,9 => CTR => B9: 2,3,7
* INC # B9: 2,3,7 => UNS
* DIS # C9: 5,9 => CTR => C9: 3,7
* INC # C9: 3,7 => UNS
* DIS # F8: 5,9 => CTR => F8: 2,4
* INC # F8: 2,4 => UNS
* INC # C1: 5,9 => UNS
* DIS # C6: 5,9 => CTR => C6: 3,7
* INC # C6: 3,7 => UNS
* DIS # I7: 2,9 => CTR => I7: 3,4
* INC # I7: 3,4 => UNS
* DIS # H8: 2,9 => CTR => H8: 7
* INC # H8: 7 => UNS
* DIS # I8: 2,9 => CTR => I8: 4,7
* INC # I8: 4,7 => UNS
* PRF # G9: 2,9 => SOL
* DIS # G9: 3 => CTR => G9: 2,9
* PRF # B7: 2,9 => SOL
* DIS # B7: 3 => CTR => B7: 2,9
* DIS # F7: 2,9 => CTR => F7: 4
* PRF # F7: 4 => SOL
* INC # H2: 2,9 => UNS
* INC # H2: 5,7 => UNS
* CNT  54 HDP CHAINS /  54 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # E2: 5,9 => UNS
* DIS # E3: 5,9 => CTR => E3: 3,7
* DIS E3: 3,7 # F3: 5,9 => CTR => F3: 3,7
* INC E3: 3,7 + F3: 3,7 # H2: 2,9 => UNS
* DIS E3: 3,7 + F3: 3,7 # I2: 2,9 => CTR => I2: 7
* INC E3: 3,7 + F3: 3,7 + I2: 7 # H2: 2,9 => UNS
* DIS E3: 3,7 + F3: 3,7 + I2: 7 # H2: 5 => CTR => H2: 2,9
* DIS E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 # G6: 2,9 => CTR => G6: 3
* PRF E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3 => SOL
* STA E3: 3,7 + F3: 3,7 + I2: 7 + H2: 2,9 + G6: 3
* CNT   9 HDP CHAINS /   8 HYP OPENED