Analysis of xx-top500-055-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...7...82.51...............6..8.9....3....1...............1.56....23....8.....4.. initial

Autosolve

position: 3..751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......185631.523.8798.3...421 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # C1: 4,9 => SOL
* DIS # C1: 6 => CTR => C1: 4,9
* PRF # E3: 6,9 => SOL
* DIS # E3: 4 => CTR => E3: 6,9
* PRF # D9: 6,9 => SOL
* DIS # F3: 2,6 => CTR => F3: 4
* PRF # F3: 4 => SOL
* DIS # C1: 6,9 => CTR => C1: 4
* PRF # C1: 4 => SOL
* DIS # C5: 2,4 => CTR => C5: 7,8,9
* DIS # C7: 2,4 => CTR => C7: 7,9
* DIS # C6: 7,8 => CTR => C6: 4,9
* DIS # B3: 2 => CTR => B3: 7,8
* PRF # E5: 2,4 => SOL
* DIS # E5: 6,7 => CTR => E5: 2,4
* PRF # A5: 4,9 => SOL
* DIS # A5: 2,7 => CTR => A5: 4,9
* DIS # C5: 4,9 => CTR => C5: 2,7,8
* DIS # C6: 7,8 => CTR => C6: 4,9
* DIS # A7: 2,7 => CTR => A7: 4,9
* DIS # B3: 2,7 => CTR => B3: 8
* PRF # D9: 6,9 => SOL
* DIS # C7: 4,9 => CTR => C7: 2,7
* DIS # F3: 2 => CTR => F3: 4,6
* CNT  24 HDP CHAINS /  45 HYP OPENED

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

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* PRF # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

...7...82.51...............6..8.9....3....1...............1.56....23....8.....4.. initial
3..751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......185631.523.8798.3...421 autosolve
394751682751682934286394715612849357438527196579163248927418563145236879863975421 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (18)
B1: 4,9
D2: 6,9
F2: 2,6
G1: 6,9
C4: 2,4
B6: 7,8
E4: 2,4
F5: 5,7
H5: 4,9
I5: 6,8
H6: 4,9
I6: 6,8
B7: 2,7
B8: 4,6
B9: 6,9
D7: 4,9
F8: 4,6
F9: 5,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F2,F3: 2.. / F2 = 2  => 19 pairs (_) / F3 = 2  =>  0 pairs (X)
E4,E5: 2.. / E4 = 2  =>  0 pairs (X) / E5 = 2  =>  0 pairs (_)
A2,F2: 2.. / A2 = 2  =>  0 pairs (X) / F2 = 2  => 19 pairs (_)
C4,E4: 2.. / C4 = 2  =>  0 pairs (*) / E4 = 2  =>  0 pairs (X)
B3,B7: 2.. / B3 = 2  =>  0 pairs (X) / B7 = 2  => 18 pairs (_)
B1,C1: 4.. / B1 = 4  =>  0 pairs (X) / C1 = 4  =>  0 pairs (_)
E3,F3: 4.. / E3 = 4  =>  0 pairs (X) / F3 = 4  =>  0 pairs (_)
H5,H6: 4.. / H5 = 4  =>  0 pairs (X) / H6 = 4  => 18 pairs (_)
D7,F8: 4.. / D7 = 4  =>  0 pairs (*) / F8 = 4  =>  0 pairs (X)
C4,E4: 4.. / C4 = 4  =>  0 pairs (X) / E4 = 4  =>  0 pairs (_)
B8,F8: 4.. / B8 = 4  =>  0 pairs (*) / F8 = 4  =>  0 pairs (X)
A5,A7: 4.. / A5 = 4  =>  0 pairs (*) / A7 = 4  =>  0 pairs (X)
B1,B8: 4.. / B1 = 4  =>  0 pairs (X) / B8 = 4  =>  0 pairs (_)
D5,D7: 4.. / D5 = 4  =>  0 pairs (X) / D7 = 4  =>  0 pairs (_)
F3,F8: 4.. / F3 = 4  =>  0 pairs (*) / F8 = 4  =>  0 pairs (X)
D5,F5: 5.. / D5 = 5  =>  0 pairs (*) / F5 = 5  =>  0 pairs (X)
D9,F9: 5.. / D9 = 5  => 18 pairs (_) / F9 = 5  =>  0 pairs (*)
D5,D9: 5.. / D5 = 5  =>  0 pairs (*) / D9 = 5  =>  0 pairs (X)
F5,F9: 5.. / F5 = 5  => 18 pairs (_) / F9 = 5  =>  0 pairs (*)
C1,C3: 6.. / C1 = 6  =>  0 pairs (X) / C3 = 6  =>  0 pairs (_)
I5,I6: 6.. / I5 = 6  => 18 pairs (_) / I6 = 6  => 17 pairs (_)
B8,B9: 6.. / B8 = 6  =>  0 pairs (X) / B9 = 6  =>  0 pairs (_)
C1,G1: 6.. / C1 = 6  =>  0 pairs (X) / G1 = 6  =>  0 pairs (_)
E6,I6: 6.. / E6 = 6  => 18 pairs (_) / I6 = 6  => 17 pairs (_)
B8,F8: 6.. / B8 = 6  =>  0 pairs (X) / F8 = 6  =>  0 pairs (_)
G2,G3: 7.. / G2 = 7  => 22 pairs (_) / G3 = 7  => 21 pairs (_)
E9,F9: 7.. / E9 = 7  =>  0 pairs (*) / F9 = 7  =>  0 pairs (X)
A2,G2: 7.. / A2 = 7  => 21 pairs (_) / G2 = 7  => 22 pairs (_)
F5,F9: 7.. / F5 = 7  =>  0 pairs (*) / F9 = 7  =>  0 pairs (X)
B3,C3: 8.. / B3 = 8  => 17 pairs (_) / C3 = 8  =>  0 pairs (X)
I5,I6: 8.. / I5 = 8  => 17 pairs (_) / I6 = 8  => 18 pairs (_)
C5,I5: 8.. / C5 = 8  => 18 pairs (_) / I5 = 8  => 17 pairs (_)
B3,B6: 8.. / B3 = 8  => 17 pairs (_) / B6 = 8  =>  0 pairs (X)
D2,E3: 9.. / D2 = 9  =>  0 pairs (X) / E3 = 9  =>  0 pairs (_)
H5,H6: 9.. / H5 = 9  => 18 pairs (_) / H6 = 9  =>  0 pairs (X)
C6,H6: 9.. / C6 = 9  => 18 pairs (_) / H6 = 9  =>  0 pairs (X)
B1,B9: 9.. / B1 = 9  =>  0 pairs (*) / B9 = 9  =>  0 pairs (X)
E3,E9: 9.. / E3 = 9  =>  0 pairs (*) / E9 = 9  =>  0 pairs (X)
* DURATION: 0:01:06.085960  START: 04:33:19.889116  END: 04:34:25.975076 2017-05-04
* CP COUNT: (38)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B6,B7,B8,B9,C4,D2,D7,E4,F2,F5,F8,F9,G1,H5,H6,I5,I6)
* 3..751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......185631.523.8798.3...421
* PAIR B1: 4,9 BLK 1
C1: 4,9,6                                # reduction candidate for 4,9
C1: 4,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
C1: 6 => CTR
* 346751982.51.8..34...3...1561.8.9357.3....1..5..1.32......18563165234879893...421
* PAIR D2: 6,9 BLK 2
E3: 6,9,4                                # reduction candidate for 6,9
E3: 6,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
E3: 4 => CTR
* 3..751.82.5198..34...34..15614829357.3.4..1..5..1.32......185631.523.8798.3...421
* PAIR D2: 6,9 ROW 2
G2: 6,9,7                                # reduction candidate for 6,9
G2: 7                                    # 22 pairs
G2: 6,9                                  # 21 pairs
* PAIR D2: 6,9 COL D
D9: 6,9,5                                # reduction candidate for 6,9
D9: 6,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
D9: 5                                    # 18 pairs
* PAIR F2: 2,6 BLK 2
F3: 2,6,4                                # reduction candidate for 2,6
F3: 2,6 => CTR
* 3..751.82.51.8..34...34..15614829357.3.4.519.5.91.324.4..918563165234879893567421
F3: 4 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
* PAIR G1: 6,9 BLK 3
G2: 6,9,7                                # reduction candidate for 6,9
G2: 6,9                                  # 21 pairs
G3: 6,9,7                                # reduction candidate for 6,9
G3: 6,9                                  # 22 pairs
* PAIR G1: 6,9 ROW 1
C1: 6,9,4                                # reduction candidate for 6,9
C1: 6,9 => CTR
* 34.751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......18563165234879893...421
C1: 4 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
* PAIR C4: 2,4 BLK 4
A5: 2,4,7,9                              # reduction candidate for 2,4
A5: 2,4                                  # 20 pairs
C5: 2,4,7,8,9                            # reduction candidate for 2,4
C5: 2,4 => CTR
* 34.751.82.51.8..34...3...1561.8.9357.3....1.85..1.32.6427918563165234879893...421
C5: 7,8,9                                # 18 pairs
* PAIR C4: 2,4 COL C
C7: 2,4,7,9                              # reduction candidate for 2,4
C7: 2,4 => CTR
* 34.751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......18563165234879893...421
C7: 7,9                                  # 19 pairs
* PAIR B6: 7,8 BLK 4
C5: 7,8,2,4,9                            # reduction candidate for 7,8
C5: 7,8                                  # 21 pairs
C6: 7,8,4,9                              # reduction candidate for 7,8
C6: 7,8 => CTR
* 3..751.82.51.8..34...3...1561.8.9357.3....14.5..1432964..918563165234879893...421
C6: 4,9                                  # 20 pairs
* PAIR B6: 7,8 COL B
B3: 7,8,2                                # reduction candidate for 7,8
B3: 2 => CTR
* 346751982.51.82.34.2839461561.8.9357.3....1.858.1.32.6.7..185631.523.879893...421
B3: 7,8                                  # 18 pairs
* PAIR E4: 2,4 BLK 5
E5: 2,4,6,7                              # reduction candidate for 2,4
E5: 2,4 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
E5: 6,7 => CTR
* 3..751.82.51.8..34...3...15614829357.3....1..5..1.32..4..918563165234879893...421
* PAIR H5: 4,9 ROW 5
A5: 4,9,2,7                              # reduction candidate for 4,9
A5: 4,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
A5: 2,7 => CTR
* 3..751.82.51.8..34...3...1561.8.9357.3....1..5..1.32..4..918563165234879893...421
C5: 4,9,2,7,8                            # reduction candidate for 4,9
C5: 4,9 => CTR
* 3..751.82.51.8..34...3...1561.8.9357.3....1.85..1.32.64..918563165234879893...421
C5: 2,7,8                                # 18 pairs
* PAIR H6: 4,9 ROW 6
C6: 4,9,7,8                              # reduction candidate for 4,9
C6: 7,8 => CTR
* 3..751.82.51.8..34...3...1561.8.9357.3....14.5..1432964..918563165234879893...421
C6: 4,9                                  # 20 pairs
* PAIR B7: 2,7 BLK 7
A7: 2,7,4,9                              # reduction candidate for 2,7
A7: 2,7 => CTR
* 3..751.82.51.8..34...3...1561.8.935743....19.5.91.324.....185631.523.8798.3...421
A7: 4,9                                  # 20 pairs
C7: 2,7,4,9                              # reduction candidate for 2,7
C7: 2,7                                  # 20 pairs
* PAIR B7: 2,7 COL B
B3: 2,7,8                                # reduction candidate for 2,7
B3: 2,7 => CTR
* 346751982.51.8..34..839461561.8.9357.3....1.858.1.32.6....185631.523.879893...421
B3: 8                                    # 17 pairs
* PAIR B9: 6,9 ROW 9
D9: 6,9,5                                # reduction candidate for 6,9
D9: 6,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
D9: 5                                    # 18 pairs
E9: 6,9,7                                # reduction candidate for 6,9
E9: 6,9                                  # 18 pairs
* PAIR D7: 4,9 ROW 7
A7: 4,9,2,7                              # reduction candidate for 4,9
A7: 4,9                                  # 20 pairs
C7: 4,9,2,7                              # reduction candidate for 4,9
C7: 4,9 => CTR
* 3..751.82.51.8..34...3...1561.8.935743....19.5.91.324...4.185631.523.8798.3...421
C7: 2,7                                  # 20 pairs
* PAIR F8: 4,6 COL F
F3: 4,6,2                                # reduction candidate for 4,6
F3: 2 => CTR
* 3..751.82.51.8..34...342.15614829357.3.4.519.5.91.324.427918563165234879893567421
F3: 4,6                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-055-base-pr-000.dot
* REASONING
* PRF # C1: 4,9 => SOL
* DIS # C1: 6 => CTR => C1: 4,9
* PRF # E3: 6,9 => SOL
* DIS # E3: 4 => CTR => E3: 6,9
* PRF # D9: 6,9 => SOL
* DIS # F3: 2,6 => CTR => F3: 4
* PRF # F3: 4 => SOL
* DIS # C1: 6,9 => CTR => C1: 4
* PRF # C1: 4 => SOL
* DIS # C5: 2,4 => CTR => C5: 7,8,9
* DIS # C7: 2,4 => CTR => C7: 7,9
* DIS # C6: 7,8 => CTR => C6: 4,9
* DIS # B3: 2 => CTR => B3: 7,8
* PRF # E5: 2,4 => SOL
* DIS # E5: 6,7 => CTR => E5: 2,4
* PRF # A5: 4,9 => SOL
* DIS # A5: 2,7 => CTR => A5: 4,9
* DIS # C5: 4,9 => CTR => C5: 2,7,8
* DIS # C6: 7,8 => CTR => C6: 4,9
* DIS # A7: 2,7 => CTR => A7: 4,9
* DIS # B3: 2,7 => CTR => B3: 8
* PRF # D9: 6,9 => SOL
* DIS # C7: 4,9 => CTR => C7: 2,7
* DIS # F3: 2 => CTR => F3: 4,6
* CNT  24 HDP CHAINS /  45 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B6,B7,B8,B9,C4,D2,D7,E4,F2,F5,F8,F9,G1,H5,H6,I5,I6)
* 3..751.82.51.8..34...3...1561.8.9357.3....1..5..1.32......185631.523.8798.3...421
* PAIR B1: 4,9 BLK 1
C1: 4,9,6                                # reduction candidate for 4,9
C1: 4,9 => SOLVED
* 394751682751682934286394715612849357438527196579163248927418563145236879863975421
* DURATION: 0:00:02.449057  START: 04:35:10.460188  END: 04:35:12.909245 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-055-base-pr-001.dot
* REASONING
* PRF # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 055

solution: 394751682751682934286394715612849357438527196579163248927418563145236879863975421
info: 1411     FNBTHWXY S8.f     11379

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

Solution

position: 394751682751682934286394715612849357438527196579163248927418563145236879863975421 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:

* PRF # C1: 4,9 => SOL
* DIS # C1: 6 => CTR => C1: 4,9
* PRF # E3: 6,9 => SOL
* DIS # E3: 4 => CTR => E3: 6,9
* INC # G2: 6,9 => UNS
* INC # G2: 7 => UNS
* PRF # D9: 6,9 => SOL
* INC # D9: 5 => UNS
* DIS # F3: 2,6 => CTR => F3: 4
* PRF # F3: 4 => SOL
* INC # G2: 6,9 => UNS
* INC # G3: 6,9 => UNS
* DIS # C1: 6,9 => CTR => C1: 4
* PRF # C1: 4 => SOL
* INC # A5: 2,4 => UNS
* DIS # C5: 2,4 => CTR => C5: 7,8,9
* INC # C5: 7,8,9 => UNS
* DIS # C7: 2,4 => CTR => C7: 7,9
* INC # C7: 7,9 => UNS
* INC # C5: 7,8 => UNS
* DIS # C6: 7,8 => CTR => C6: 4,9
* INC # C6: 4,9 => UNS
* INC # B3: 7,8 => UNS
* DIS # B3: 2 => CTR => B3: 7,8
* PRF # E5: 2,4 => SOL
* DIS # E5: 6,7 => CTR => E5: 2,4
* PRF # A5: 4,9 => SOL
* DIS # A5: 2,7 => CTR => A5: 4,9
* DIS # C5: 4,9 => CTR => C5: 2,7,8
* INC # C5: 2,7,8 => UNS
* INC # C6: 4,9 => UNS
* DIS # C6: 7,8 => CTR => C6: 4,9
* DIS # A7: 2,7 => CTR => A7: 4,9
* INC # A7: 4,9 => UNS
* INC # C7: 2,7 => UNS
* DIS # B3: 2,7 => CTR => B3: 8
* INC # B3: 8 => UNS
* PRF # D9: 6,9 => SOL
* INC # D9: 5 => UNS
* INC # E9: 6,9 => UNS
* INC # A7: 4,9 => UNS
* DIS # C7: 4,9 => CTR => C7: 2,7
* INC # C7: 2,7 => UNS
* INC # F3: 4,6 => UNS
* DIS # F3: 2 => CTR => F3: 4,6
* CNT  45 HDP CHAINS /  45 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED