Analysis of xx-top500-324-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .......127...6...........5..8.2.....6.....4.....1.9....19..........3.8..5.2...... initial

Autosolve

position: .......127...6...........5..8.2.6...6.....4.....1.9...819......4...3.8..532...... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A3: 3,9 => CTR => A3: 1,2
* DIS # D1: 3,9 => CTR => D1: 4,5,7,8
* DIS # G1: 3,9 => CTR => G1: 6,7
* PRF # A4: 3,9 => SOL
* DIS # A4: 1 => CTR => A4: 3,9
* DIS # G1: 3,9 => CTR => G1: 6,7
* DIS # G4: 3,9 => CTR => G4: 1,5,7
* DIS # H6: 2,3 => CTR => H6: 6,7,8
* DIS # A3: 2,3 => CTR => A3: 1,9
* PRF # A3: 1,9 => SOL
* DIS # I8: 5,9 => CTR => I8: 1
* PRF # I8: 1 => SOL
* DIS # H5: 7,8 => CTR => H5: 2,9
* CNT  13 HDP CHAINS /  29 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 # A3: 3,9 => CTR => A3: 1,2
* DIS A3: 1,2 # D1: 3,9 => CTR => D1: 4,5,7,8
* DIS A3: 1,2 + D1: 4,5,7,8 # G1: 3,9 => CTR => G1: 6,7
* PRF A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 # A4: 3,9 => SOL
* STA A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 + A4: 3,9
* CNT   4 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.......127...6...........5..8.2.....6.....4.....1.9....19..........3.8..5.2...... initial
.......127...6...........5..8.2.6...6.....4.....1.9...819......4...3.8..532...... autosolve
346895712725361984198427356984256173651783429273149568819674235467532891532918647 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
A1: 3,9
G2: 3,9
A6: 2,3
B8: 6,7
C8: 6,7
D8: 5,9
H8: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C2,F2: 1.. / C2 = 1  =>  0 pairs (X) / F2 = 1  =>  0 pairs (_)
C5,I5: 1.. / C5 = 1  =>  0 pairs (*) / I5 = 1  =>  0 pairs (X)
F8,I8: 1.. / F8 = 1  =>  0 pairs (X) / I8 = 1  =>  0 pairs (_)
A3,A4: 1.. / A3 = 1  =>  0 pairs (*) / A4 = 1  =>  0 pairs (X)
E3,E9: 1.. / E3 = 1  =>  0 pairs (X) / E9 = 1  =>  0 pairs (_)
G4,G9: 1.. / G4 = 1  =>  0 pairs (*) / G9 = 1  =>  0 pairs (X)
B2,F2: 2.. / B2 = 2  =>  0 pairs (*) / F2 = 2  =>  0 pairs (X)
B5,H5: 2.. / B5 = 2  =>  0 pairs (X) / H5 = 2  =>  0 pairs (_)
F8,H8: 2.. / F8 = 2  =>  0 pairs (*) / H8 = 2  =>  0 pairs (X)
A3,A6: 2.. / A3 = 2  =>  0 pairs (X) / A6 = 2  =>  0 pairs (_)
E3,E7: 2.. / E3 = 2  =>  0 pairs (*) / E7 = 2  =>  0 pairs (X)
G6,G7: 2.. / G6 = 2  =>  0 pairs (X) / G7 = 2  =>  0 pairs (_)
D5,F5: 3.. / D5 = 3  =>  7 pairs (_) / F5 = 3  =>  7 pairs (_)
E4,E6: 4.. / E4 = 4  =>  7 pairs (_) / E6 = 4  =>  8 pairs (_)
C4,E4: 4.. / C4 = 4  =>  8 pairs (_) / E4 = 4  =>  7 pairs (_)
B8,C8: 6.. / B8 = 6  =>  6 pairs (_) / C8 = 6  =>  5 pairs (_)
D7,D9: 6.. / D7 = 6  =>  7 pairs (_) / D9 = 6  =>  7 pairs (_)
B8,C8: 7.. / B8 = 7  =>  5 pairs (_) / C8 = 7  =>  6 pairs (_)
A4,B5: 9.. / A4 = 9  =>  0 pairs (*) / B5 = 9  =>  0 pairs (X)
* DURATION: 0:00:26.860477  START: 13:58:02.029217  END: 13:58:28.889694 2017-05-04
* CP COUNT: (19)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B8,C8,D8,G2,H8)
* .......127...6...........5..8.2.6...6.....4.....1.9...819......4...3.8..532......
* PAIR A1: 3,9 BLK 1
A3: 3,9,1,2                              # reduction candidate for 3,9
A3: 3,9 => CTR
* .......127...6...........5.18.2.6...69....4212..1.9...819...2..4...3.8..532......
A3: 1,2                                  #  8 pairs
* PAIR A1: 3,9 ROW 1
D1: 3,9,4,5,7,8                          # reduction candidate for 3,9
D1: 3,9 => CTR
* 9..3...127...62...2......5.18.2.6...62...34.13..1.92..819.2....4...3182.532.9.1..
D1: 4,5,7,8                              #  7 pairs
G1: 3,9,6,7                              # reduction candidate for 3,9
G1: 3,9 => CTR
* 9.....31275..629..24.....5.18.2.6...62....4.137.1.92..819.2....46..3.82.532......
G1: 6,7                                  #  8 pairs
* PAIR A1: 3,9 COL A
A4: 3,9,1                                # reduction candidate for 3,9
A4: 3,9 => SOLVED
* 346895712725361984198427356984256173651783429273149568819674235467532891532918647
A4: 1 => CTR
* .......127...6...........5.18.2.6...69....421...1.9...819...2..4...3.8..532......
* PAIR G2: 3,9 BLK 3
G1: 3,9,6,7                              # reduction candidate for 3,9
G1: 3,9 => CTR
* 9.....31275..629..24.....5.18.2.6...62....4.137.1.92..819.2....46..3.82.532......
G1: 6,7                                  #  8 pairs
H2: 3,9,4,8                              # reduction candidate for 3,9
H2: 3,9                                  # 13 pairs
I2: 3,9,4,8                              # reduction candidate for 3,9
I2: 3,9                                  # 13 pairs
G3: 3,9,6,7                              # reduction candidate for 3,9
G3: 3,9                                  # 12 pairs
I3: 3,9,4,6,7,8                          # reduction candidate for 3,9
I3: 3,9                                  # 13 pairs
* PAIR G2: 3,9 ROW 2
D2: 3,9,4,5,8                            # reduction candidate for 3,9
D2: 3,9                                  # 12 pairs
D2: 4,5,8                                #  7 pairs
* PAIR G2: 3,9 COL G
G4: 3,9,1,5,7                            # reduction candidate for 3,9
G4: 3,9 => CTR
* .......127...6........1..5.18.2.6...69....421...1.9...819.2....4...3.8..532...1..
G4: 1,5,7                                #  7 pairs
* PAIR A6: 2,3 ROW 6
G6: 2,3,5,6,7                            # reduction candidate for 2,3
G6: 2,3                                  #  8 pairs
H6: 2,3,6,7,8                            # reduction candidate for 2,3
H6: 2,3 => CTR
* .......1272..6..4.....2..57.8.2.61..6.....4.....1.9...819...2..4...32891532...7.4
H6: 6,7,8                                #  7 pairs
* PAIR A6: 2,3 COL A
A3: 2,3,1,9                              # reduction candidate for 2,3
A3: 2,3 => CTR
* .......127...6...........5.18.2.6...69....421...1.9...819...2..4...3.8..532......
A3: 1,9 => SOLVED
* 346895712725361984198427356984256173651783429273149568819674235467532891532918647
* PAIR D8: 5,9 ROW 8
I8: 5,9,1                                # reduction candidate for 5,9
I8: 5,9 => CTR
* .......127.1.6........1..5.18.2.6...6.....4.....1.9...819......4...3182.532......
I8: 1 => SOLVED
* 346895712725361984198427356984256173651783429273149568819674235467532891532918647
* PAIR D8: 5,9 COL D
D1: 5,9,3,4,7,8                          # reduction candidate for 5,9
D1: 5,9                                  # 10 pairs
D2: 5,9,3,4,8                            # reduction candidate for 5,9
D2: 5,9                                  #  8 pairs
* PAIR H8: 2,9 COL H
H5: 2,9,7,8                              # reduction candidate for 2,9
H5: 7,8 => CTR
* 9......127...62...2......5.18.2.6...62....4.93..1.9...819.2....4...3.82.532...19.
H5: 2,9                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-324-base-pr-000.dot
* REASONING
* DIS # A3: 3,9 => CTR => A3: 1,2
* DIS # D1: 3,9 => CTR => D1: 4,5,7,8
* DIS # G1: 3,9 => CTR => G1: 6,7
* PRF # A4: 3,9 => SOL
* DIS # A4: 1 => CTR => A4: 3,9
* DIS # G1: 3,9 => CTR => G1: 6,7
* DIS # G4: 3,9 => CTR => G4: 1,5,7
* DIS # H6: 2,3 => CTR => H6: 6,7,8
* DIS # A3: 2,3 => CTR => A3: 1,9
* PRF # A3: 1,9 => SOL
* DIS # I8: 5,9 => CTR => I8: 1
* PRF # I8: 1 => SOL
* DIS # H5: 7,8 => CTR => H5: 2,9
* CNT  13 HDP CHAINS /  29 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B8,C8,D8,G2,H8)
* .......127...6...........5..8.2.6...6.....4.....1.9...819......4...3.8..532......
* PAIR A1: 3,9 BLK 1
A3: 3,9,1,2                              # reduction candidate for 3,9
A3: 3,9 => CTR
* .......127...6...........5.18.2.6...69....4212..1.9...819...2..4...3.8..532......
* PAIR A1: 3,9 ROW 1
D1: 3,9,4,5,7,8                          # reduction candidate for 3,9
D1: 3,9 => CTR
* 9..3...127...62...2......5.18.2.6...62...34.13..1.92..819.2....4...3182.532.9.1..
G1: 3,9,6,7                              # reduction candidate for 3,9
G1: 3,9 => CTR
* 9.....31275..629..24.....5.18.2.6...62....4.137.1.92..819.2....46..3.82.532......
* RESTART
* PAIR A1: 3,9 COL A
A4: 3,9,1                                # reduction candidate for 3,9
A4: 3,9 => SOLVED
* 346895712725361984198427356984256173651783429273149568819674235467532891532918647
* DURATION: 0:00:05.399289  START: 13:58:48.546233  END: 13:58:53.945522 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-324-base-pr-001.dot
* REASONING
* DIS # A3: 3,9 => CTR => A3: 1,2
* DIS A3: 1,2 # D1: 3,9 => CTR => D1: 4,5,7,8
* DIS A3: 1,2 + D1: 4,5,7,8 # G1: 3,9 => CTR => G1: 6,7
* PRF A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 # A4: 3,9 => SOL
* STA A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 + A4: 3,9
* CNT   4 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 324

solution: 346895712725361984198427356984256173651783429273149568819674235467532891532918647
info: 2963     FNBHWY   S8.f     11

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

Solution

position: 346895712725361984198427356984256173651783429273149568819674235467532891532918647 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 # A3: 3,9 => CTR => A3: 1,2
* INC # A3: 1,2 => UNS
* DIS # D1: 3,9 => CTR => D1: 4,5,7,8
* INC # D1: 4,5,7,8 => UNS
* DIS # G1: 3,9 => CTR => G1: 6,7
* INC # G1: 6,7 => UNS
* PRF # A4: 3,9 => SOL
* DIS # A4: 1 => CTR => A4: 3,9
* DIS # G1: 3,9 => CTR => G1: 6,7
* INC # G1: 6,7 => UNS
* INC # H2: 3,9 => UNS
* INC # I2: 3,9 => UNS
* INC # G3: 3,9 => UNS
* INC # I3: 3,9 => UNS
* INC # D2: 3,9 => UNS
* INC # D2: 4,5,8 => UNS
* DIS # G4: 3,9 => CTR => G4: 1,5,7
* INC # G4: 1,5,7 => UNS
* INC # G6: 2,3 => UNS
* DIS # H6: 2,3 => CTR => H6: 6,7,8
* INC # H6: 6,7,8 => UNS
* DIS # A3: 2,3 => CTR => A3: 1,9
* PRF # A3: 1,9 => SOL
* DIS # I8: 5,9 => CTR => I8: 1
* PRF # I8: 1 => SOL
* INC # D1: 5,9 => UNS
* INC # D2: 5,9 => UNS
* INC # H5: 2,9 => UNS
* DIS # H5: 7,8 => CTR => H5: 2,9
* CNT  29 HDP CHAINS /  29 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A3: 3,9 => CTR => A3: 1,2
* DIS A3: 1,2 # D1: 3,9 => CTR => D1: 4,5,7,8
* DIS A3: 1,2 + D1: 4,5,7,8 # G1: 3,9 => CTR => G1: 6,7
* PRF A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 # A4: 3,9 => SOL
* STA A3: 1,2 + D1: 4,5,7,8 + G1: 6,7 + A4: 3,9
* CNT   4 HDP CHAINS /   4 HYP OPENED