Analysis of xx-top500-328-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .4.5...6..17...............8......2.....13......4.7.........1.35..6.........8.7.. initial

Autosolve

position: .4.5...6..17...............8..9...2....813......427.........1.35..6.........8.7.6 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D3: 2,3 => CTR => D3: 1,7
* DIS # A2: 2,3 => CTR => A2: 6,9
* DIS # G2: 2,3 => CTR => G2: 4,5,8,9
* PRF # D9: 2,3 => SOL
* DIS # D9: 1 => CTR => D9: 2,3
* DIS # B8: 8,9 => CTR => B8: 3,7
* DIS # C4: 3,4 => CTR => C4: 1
* PRF # C4: 1 => SOL
* DIS # B7: 2,7 => CTR => B7: 6,8,9
* DIS # D3: 2,7 => CTR => D3: 1,3
* PRF # D3: 1,3 => SOL
* CNT  11 HDP CHAINS /  19 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: 2,3 => CTR => D3: 1,7
* DIS D3: 1,7 # A2: 2,3 => CTR => A2: 6,9
* DIS D3: 1,7 + A2: 6,9 # G2: 2,3 => CTR => G2: 4,5,8,9
* PRF D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 # D9: 2,3 => SOL
* STA D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 + D9: 2,3
* CNT   4 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.4.5...6..17...............8......2.....13......4.7.........1.35..6.........8.7.. initial
.4.5...6..17...............8..9...2....813......427.........1.35..6.........8.7.6 autosolve
348579261917268534265134879831956427724813695659427318486792153573641982192385746 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (6)
D2: 2,3
B4: 3,7
E4: 5,6
F4: 5,6
G4: 3,4
D7: 2,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F1,I1: 1.. / F1 = 1  =>  0 pairs (X) / I1 = 1  =>  0 pairs (_)
C4,I4: 1.. / C4 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
C8,F8: 1.. / C8 = 1  =>  0 pairs (X) / F8 = 1  =>  0 pairs (_)
A6,A9: 1.. / A6 = 1  =>  0 pairs (X) / A9 = 1  =>  0 pairs (_)
D3,D9: 1.. / D3 = 1  =>  0 pairs (*) / D9 = 1  =>  0 pairs (X)
H3,H6: 1.. / H3 = 1  =>  0 pairs (X) / H6 = 1  =>  0 pairs (_)
G8,I8: 2.. / G8 = 2  =>  6 pairs (_) / I8 = 2  =>  6 pairs (_)
E8,D9: 3.. / E8 = 3  =>  0 pairs (X) / D9 = 3  =>  0 pairs (_)
B3,C3: 5.. / B3 = 5  =>  6 pairs (_) / C3 = 5  =>  6 pairs (_)
G2,I2: 5.. / G2 = 5  =>  6 pairs (_) / I2 = 5  =>  8 pairs (_)
E4,F4: 5.. / E4 = 5  =>  4 pairs (_) / F4 = 5  =>  4 pairs (_)
H7,H9: 5.. / H7 = 5  =>  5 pairs (_) / H9 = 5  =>  6 pairs (_)
F9,H9: 5.. / F9 = 5  =>  5 pairs (_) / H9 = 5  =>  6 pairs (_)
E4,E7: 5.. / E4 = 5  =>  4 pairs (_) / E7 = 5  =>  4 pairs (_)
E4,F4: 6.. / E4 = 6  =>  4 pairs (_) / F4 = 6  =>  4 pairs (_)
G5,G6: 6.. / G5 = 6  =>  6 pairs (_) / G6 = 6  =>  6 pairs (_)
E1,I1: 7.. / E1 = 7  =>  0 pairs (*) / I1 = 7  =>  0 pairs (X)
B4,I4: 7.. / B4 = 7  =>  0 pairs (X) / I4 = 7  =>  0 pairs (_)
B8,E8: 7.. / B8 = 7  =>  0 pairs (*) / E8 = 7  =>  0 pairs (X)
A5,A7: 7.. / A5 = 7  =>  0 pairs (*) / A7 = 7  =>  0 pairs (X)
D3,D7: 7.. / D3 = 7  =>  0 pairs (X) / D7 = 7  =>  0 pairs (_)
H3,H5: 7.. / H3 = 7  =>  0 pairs (*) / H5 = 7  =>  0 pairs (X)
* DURATION: 0:00:31.394652  START: 14:02:59.164332  END: 14:03:30.558984 2017-05-04
* CP COUNT: (22)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B4,D2,D7,E4,F4,G4)
* .4.5...6..17...............8..9...2....813......427.........1.35..6.........8.7.6
* PAIR D2: 2,3 BLK 2
D3: 2,3,1,7                              # reduction candidate for 2,3
D3: 2,3 => CTR
* .4.5...6..17...............83.9..4277.4813.951..427......7..1.357.6........18.7.6
D3: 1,7                                  #  7 pairs
* PAIR D2: 2,3 ROW 2
A2: 2,3,6,9                              # reduction candidate for 2,3
A2: 2,3 => CTR
* .4.5...6..17...............8..9...2....813.7....427...7..2..1.35..67.......38.7.6
A2: 6,9                                  #  7 pairs
G2: 2,3,4,5,8,9                          # reduction candidate for 2,3
G2: 2,3 => CTR
* .4.5...6..17.....5.........8..9...2....813.7....427..87..2..1.35..67.......38.7.6
G2: 4,5,8,9                              #  6 pairs
* PAIR D2: 2,3 COL D
D9: 2,3,1                                # reduction candidate for 2,3
D9: 2,3 => SOLVED
* 348579261917268534265134879831956427724813695659427318486792153573641982192385746
D9: 1 => CTR
* .4.5...6..17...............8..9...2....813...1..427.........1.357163.......18.7.6
* PAIR B4: 3,7 COL B
B8: 3,7,8,9                              # reduction candidate for 3,7
B8: 8,9 => CTR
* .4.5...6..17...............8..9...2....813......427.........1.35..67.......38.7.6
B8: 3,7                                  #  8 pairs
* PAIR G4: 3,4 ROW 4
C4: 3,4,1                                # reduction candidate for 3,4
C4: 3,4 => CTR
* .4.5.1.6..17.............1.87.9...21...813.7....427...7..2..1.35.167........8.7.6
C4: 1 => SOLVED
* 348579261917268534265134879831956427724813695659427318486792153573641982192385746
* PAIR G4: 3,4 COL G
G2: 3,4,2,5,8,9                          # reduction candidate for 3,4
G2: 3,4                                  #  9 pairs
G3: 3,4,2,8,9                            # reduction candidate for 3,4
G3: 3,4                                  #  7 pairs
* PAIR D7: 2,7 ROW 7
A7: 2,7,4,6,9                            # reduction candidate for 2,7
A7: 2,7                                  #  7 pairs
B7: 2,7,6,8,9                            # reduction candidate for 2,7
B7: 2,7 => CTR
* .4.57..6..17...53..8513..7.8319..427724813.95...427.18...7..1.357.6.....1...8.7.6
B7: 6,8,9                                #  6 pairs
* PAIR D7: 2,7 COL D
D3: 2,7,1,3                              # reduction candidate for 2,7
D3: 2,7 => CTR
* .4.5...6..173............1.8..9...21...813.7.1..427.3.7..2..1.35.163.......18.7.6
D3: 1,3 => SOLVED
* 348579261917268534265134879831956427724813695659427318486792153573641982192385746
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-328-base-pr-000.dot
* REASONING
* DIS # D3: 2,3 => CTR => D3: 1,7
* DIS # A2: 2,3 => CTR => A2: 6,9
* DIS # G2: 2,3 => CTR => G2: 4,5,8,9
* PRF # D9: 2,3 => SOL
* DIS # D9: 1 => CTR => D9: 2,3
* DIS # B8: 8,9 => CTR => B8: 3,7
* DIS # C4: 3,4 => CTR => C4: 1
* PRF # C4: 1 => SOL
* DIS # B7: 2,7 => CTR => B7: 6,8,9
* DIS # D3: 2,7 => CTR => D3: 1,3
* PRF # D3: 1,3 => SOL
* CNT  11 HDP CHAINS /  19 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B4,D2,D7,E4,F4,G4)
* .4.5...6..17...............8..9...2....813......427.........1.35..6.........8.7.6
* PAIR D2: 2,3 BLK 2
D3: 2,3,1,7                              # reduction candidate for 2,3
D3: 2,3 => CTR
* .4.5...6..17...............83.9..4277.4813.951..427......7..1.357.6........18.7.6
* PAIR D2: 2,3 ROW 2
A2: 2,3,6,9                              # reduction candidate for 2,3
A2: 2,3 => CTR
* .4.5...6..17...............8..9...2....813.7....427...7..2..1.35..67.......38.7.6
G2: 2,3,4,5,8,9                          # reduction candidate for 2,3
G2: 2,3 => CTR
* .4.5...6..17.....5.........8..9...2....813.7....427..87..2..1.35..67.......38.7.6
* RESTART
* PAIR D2: 2,3 COL D
D9: 2,3,1                                # reduction candidate for 2,3
D9: 2,3 => SOLVED
* 348579261917268534265134879831956427724813695659427318486792153573641982192385746
* DURATION: 0:00:05.289574  START: 14:03:44.818565  END: 14:03:50.108139 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-328-base-pr-001.dot
* REASONING
* DIS # D3: 2,3 => CTR => D3: 1,7
* DIS D3: 1,7 # A2: 2,3 => CTR => A2: 6,9
* DIS D3: 1,7 + A2: 6,9 # G2: 2,3 => CTR => G2: 4,5,8,9
* PRF D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 # D9: 2,3 => SOL
* STA D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 + D9: 2,3
* CNT   4 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 328

solution: 348579261917268534265134879831956427724813695659427318486792153573641982192385746
info: 2965     FNBHWY   S8.f     19113

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

Solution

position: 348579261917268534265134879831956427724813695659427318486792153573641982192385746 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 # D3: 2,3 => CTR => D3: 1,7
* INC # D3: 1,7 => UNS
* DIS # A2: 2,3 => CTR => A2: 6,9
* INC # A2: 6,9 => UNS
* DIS # G2: 2,3 => CTR => G2: 4,5,8,9
* INC # G2: 4,5,8,9 => UNS
* PRF # D9: 2,3 => SOL
* DIS # D9: 1 => CTR => D9: 2,3
* INC # B8: 3,7 => UNS
* DIS # B8: 8,9 => CTR => B8: 3,7
* DIS # C4: 3,4 => CTR => C4: 1
* PRF # C4: 1 => SOL
* INC # G2: 3,4 => UNS
* INC # G3: 3,4 => UNS
* INC # A7: 2,7 => UNS
* DIS # B7: 2,7 => CTR => B7: 6,8,9
* INC # B7: 6,8,9 => UNS
* DIS # D3: 2,7 => CTR => D3: 1,3
* PRF # D3: 1,3 => SOL
* CNT  19 HDP CHAINS /  19 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D3: 2,3 => CTR => D3: 1,7
* DIS D3: 1,7 # A2: 2,3 => CTR => A2: 6,9
* DIS D3: 1,7 + A2: 6,9 # G2: 2,3 => CTR => G2: 4,5,8,9
* PRF D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 # D9: 2,3 => SOL
* STA D3: 1,7 + A2: 6,9 + G2: 4,5,8,9 + D9: 2,3
* CNT   4 HDP CHAINS /   4 HYP OPENED