Analysis of xx-top500-171-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .9.5............1.........4...82.9..7.....3....1......4....1.6....6...7..2....5.. initial

Autosolve

position: .9451673..6.4...15.1....6946438279517..1..3.6..1.6.4.747...1.6..3.6..17.126...54. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I7: 2,8 => CTR => I7: 3,9
* DIS # F6: 3,9 => CTR => F6: 5
* PRF # D7: 3,9 => SOL
* DIS # D7: 2 => CTR => D7: 3,9
* DIS # D9: 3,9 => CTR => D9: 7
* DIS # I7: 2,8 => CTR => I7: 3,9
* CNT   6 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 # I7: 2,8 => CTR => I7: 3,9
* DIS I7: 3,9 # I8: 9 => CTR => I8: 2,8
* PRF I7: 3,9 + I8: 2,8 # A2: 2,8 => SOL
* STA I7: 3,9 + I8: 2,8 + A2: 2,8
* CNT   3 HDP CHAINS /   9 HYP OPENED

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

Details

Positions

.9.5............1.........4...82.9..7.....3....1......4....1.6....6...7..2....5.. initial
.9451673..6.4...15.1....6946438279517..1..3.6..1.6.4.747...1.6..3.6..17.126...54. autosolve
894516732267439815315278694643827951752194386981365427478951263539642178126783549 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
A1: 2,8
I1: 2,8
G2: 2,8
B5: 5,8
C5: 2,9
A6: 2,9
B6: 5,8
D6: 3,9
H5: 2,8
H6: 2,8
G7: 2,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I1,G2: 2.. / I1 = 2  =>  0 pairs (*) / G2 = 2  =>  0 pairs (X)
C5,A6: 2.. / C5 = 2  => 12 pairs (_) / A6 = 2  =>  0 pairs (X)
H5,H6: 2.. / H5 = 2  =>  0 pairs (X) / H6 = 2  => 12 pairs (_)
D7,F8: 2.. / D7 = 2  =>  0 pairs (X) / F8 = 2  =>  0 pairs (_)
A1,I1: 2.. / A1 = 2  => 15 pairs (_) / I1 = 2  =>  0 pairs (*)
C5,H5: 2.. / C5 = 2  => 12 pairs (_) / H5 = 2  =>  0 pairs (X)
A6,H6: 2.. / A6 = 2  =>  0 pairs (X) / H6 = 2  => 12 pairs (_)
F8,I8: 2.. / F8 = 2  =>  0 pairs (*) / I8 = 2  =>  0 pairs (X)
D3,D7: 2.. / D3 = 2  =>  0 pairs (*) / D7 = 2  =>  0 pairs (X)
G2,G7: 2.. / G2 = 2  => 15 pairs (_) / G7 = 2  =>  0 pairs (*)
A2,A3: 3.. / A2 = 3  => 11 pairs (_) / A3 = 3  => 19 pairs (_)
D6,F6: 3.. / D6 = 3  => 15 pairs (_) / F6 = 3  =>  0 pairs (X)
I7,I9: 3.. / I7 = 3  => 13 pairs (_) / I9 = 3  => 16 pairs (_)
E5,F5: 4.. / E5 = 4  =>  0 pairs (X) / F5 = 4  => 12 pairs (_)
E8,F8: 4.. / E8 = 4  => 12 pairs (_) / F8 = 4  =>  0 pairs (X)
E5,E8: 4.. / E5 = 4  =>  0 pairs (X) / E8 = 4  => 12 pairs (_)
F5,F8: 4.. / F5 = 4  => 12 pairs (_) / F8 = 4  =>  0 pairs (X)
A3,C3: 5.. / A3 = 5  => 12 pairs (_) / C3 = 5  => 14 pairs (_)
B5,B6: 5.. / B5 = 5  => 12 pairs (_) / B6 = 5  =>  0 pairs (X)
B6,F6: 5.. / B6 = 5  =>  0 pairs (X) / F6 = 5  => 12 pairs (_)
C7,E7: 5.. / C7 = 5  =>  0 pairs (X) / E7 = 5  => 13 pairs (_)
A3,A8: 5.. / A3 = 5  => 12 pairs (_) / A8 = 5  => 14 pairs (_)
C2,C3: 7.. / C2 = 7  => 11 pairs (_) / C3 = 7  => 18 pairs (_)
D9,E9: 7.. / D9 = 7  => 12 pairs (_) / E9 = 7  =>  0 pairs (X)
C2,E2: 7.. / C2 = 7  => 11 pairs (_) / E2 = 7  => 18 pairs (_)
D3,D9: 7.. / D3 = 7  =>  0 pairs (X) / D9 = 7  => 12 pairs (_)
I1,G2: 8.. / I1 = 8  => 15 pairs (_) / G2 = 8  =>  0 pairs (*)
B5,B6: 8.. / B5 = 8  =>  0 pairs (X) / B6 = 8  => 12 pairs (_)
H5,H6: 8.. / H5 = 8  => 12 pairs (_) / H6 = 8  =>  0 pairs (X)
A1,I1: 8.. / A1 = 8  =>  0 pairs (*) / I1 = 8  =>  0 pairs (X)
B5,H5: 8.. / B5 = 8  =>  0 pairs (X) / H5 = 8  => 12 pairs (_)
B6,H6: 8.. / B6 = 8  => 12 pairs (_) / H6 = 8  =>  0 pairs (X)
G2,G7: 8.. / G2 = 8  =>  0 pairs (*) / G7 = 8  =>  0 pairs (X)
E2,F2: 9.. / E2 = 9  => 12 pairs (_) / F2 = 9  => 14 pairs (_)
C5,A6: 9.. / C5 = 9  =>  0 pairs (X) / A6 = 9  => 12 pairs (_)
A6,A8: 9.. / A6 = 9  => 12 pairs (_) / A8 = 9  =>  0 pairs (X)
* DURATION: 0:00:57.867257  START: 08:34:42.208270  END: 08:35:40.075527 2017-05-04
* CP COUNT: (36)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B5,B6,C5,D6,G2,G7,H5,H6,I1)
* .9451673..6.4...15.1....6946438279517..1..3.6..1.6.4.747...1.6..3.6..17.126...54.
* PAIR A1: 2,8 BLK 1
A2: 2,8,3                                # reduction candidate for 2,8
A2: 2,8                                  # 19 pairs
C2: 2,8,7                                # reduction candidate for 2,8
C2: 2,8                                  # 18 pairs
A3: 2,8,3,5                              # reduction candidate for 2,8
A3: 2,8                                  # 18 pairs
C3: 2,8,5,7                              # reduction candidate for 2,8
C3: 2,8                                  # 14 pairs
* PAIR I1: 2,8 COL I
I7: 2,8,3,9                              # reduction candidate for 2,8
I7: 2,8 => CTR
* .9451673..6.4...15.1....6946438279517..1..3.69.13654274792.1.6..3.6..179126...543
I7: 3,9                                  # 12 pairs
I8: 2,8,9                                # reduction candidate for 2,8
I8: 2,8                                  # 14 pairs
* PAIR G2: 2,8 ROW 2
A2: 2,8,3                                # reduction candidate for 2,8
A2: 2,8                                  # 19 pairs
C2: 2,8,7                                # reduction candidate for 2,8
C2: 2,8                                  # 18 pairs
F2: 2,8,3,9                              # reduction candidate for 2,8
F2: 2,8                                  # 13 pairs
* PAIR D6: 3,9 BLK 5
F6: 3,9,5                                # reduction candidate for 3,9
F6: 3,9 => CTR
* 89451673236.4..81551....6946438279517891..326251.6.48747...126.93.6.2178126...54.
F6: 5                                    # 12 pairs
* PAIR D6: 3,9 COL D
D7: 3,9,2                                # reduction candidate for 3,9
D7: 3,9 => SOLVED
* 894516732267439815315278694643827951752194386981365427478951263539642178126783549
D7: 2 => CTR
* 294516738.674.32153157826946438279517.21..38698136542747.2.186..3.6..172126978543
D9: 3,9,7                                # reduction candidate for 3,9
D9: 3,9 => CTR
* 294516738.674..215.1.7.26946438279517.21..38698136542747.231869.39654172126978543
D9: 7                                    # 12 pairs
* PAIR G7: 2,8 BLK 9
I7: 2,8,3,9                              # reduction candidate for 2,8
I7: 2,8 => CTR
* .9451673..6.4...15.1....6946438279517..1..3.69.13654274792.1.6..3.6..179126...543
I7: 3,9                                  # 12 pairs
I8: 2,8,9                                # reduction candidate for 2,8
I8: 2,8                                  # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-171-base-pr-000.dot
* REASONING
* DIS # I7: 2,8 => CTR => I7: 3,9
* DIS # F6: 3,9 => CTR => F6: 5
* PRF # D7: 3,9 => SOL
* DIS # D7: 2 => CTR => D7: 3,9
* DIS # D9: 3,9 => CTR => D9: 7
* DIS # I7: 2,8 => CTR => I7: 3,9
* CNT   6 HDP CHAINS /  19 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B5,B6,C5,D6,G2,G7,H5,H6,I1)
* .9451673..6.4...15.1....6946438279517..1..3.6..1.6.4.747...1.6..3.6..17.126...54.
* PAIR A1: 2,8 BLK 1
A2: 2,8,3                                # reduction candidate for 2,8
A2: 2,8                                  # 19 pairs
C2: 2,8,7                                # reduction candidate for 2,8
C2: 2,8                                  # 18 pairs
A3: 2,8,3,5                              # reduction candidate for 2,8
A3: 2,8                                  # 18 pairs
C3: 2,8,5,7                              # reduction candidate for 2,8
C3: 2,8                                  # 14 pairs
* PAIR I1: 2,8 COL I
I7: 2,8,3,9                              # reduction candidate for 2,8
I7: 2,8 => CTR
* .9451673..6.4...15.1....6946438279517..1..3.69.13654274792.1.6..3.6..179126...543
I8: 2,8,9                                # reduction candidate for 2,8
I8: 2,8                                  # 14 pairs
* RESTART
* PAIR I1: 2,8 COL I
I8: 2,8,9                                # reduction candidate for 2,8
I8: 9 => CTR
* 894516732.6.4..815.1.2.86946438279517..1.43.69.1365427479..126..3.6.2179126...548
* PAIR RESTART
* PAIR G2: 2,8 ROW 2
A2: 2,8,3                                # reduction candidate for 2,8
A2: 2,8 => SOLVED
* 894516732267439815315278694643827951752194386981365427478951263539642178126783549
* DURATION: 0:00:09.343236  START: 08:35:57.752258  END: 08:36:07.095494 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-171-base-pr-001.dot
* REASONING
* DIS # I7: 2,8 => CTR => I7: 3,9
* DIS I7: 3,9 # I8: 9 => CTR => I8: 2,8
* PRF I7: 3,9 + I8: 2,8 # A2: 2,8 => SOL
* STA I7: 3,9 + I8: 2,8 + A2: 2,8
* CNT   3 HDP CHAINS /   9 HYP OPENED

Header Info

Top 500 Minimum 17 171

solution: 894516732267439815315278694643827951752194386981365427478951263539642178126783549
info: 1826     FNBTWXY  S8.f     24550

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

Solution

position: 894516732267439815315278694643827951752194386981365427478951263539642178126783549 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 # A2: 2,8 => UNS
* INC # C2: 2,8 => UNS
* INC # A3: 2,8 => UNS
* INC # C3: 2,8 => UNS
* DIS # I7: 2,8 => CTR => I7: 3,9
* INC # I7: 3,9 => UNS
* INC # I8: 2,8 => UNS
* INC # A2: 2,8 => UNS
* INC # C2: 2,8 => UNS
* INC # F2: 2,8 => UNS
* DIS # F6: 3,9 => CTR => F6: 5
* INC # F6: 5 => UNS
* PRF # D7: 3,9 => SOL
* DIS # D7: 2 => CTR => D7: 3,9
* DIS # D9: 3,9 => CTR => D9: 7
* INC # D9: 7 => UNS
* DIS # I7: 2,8 => CTR => I7: 3,9
* INC # I7: 3,9 => UNS
* INC # I8: 2,8 => UNS
* CNT  19 HDP CHAINS /  19 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A2: 2,8 => UNS
* INC # C2: 2,8 => UNS
* INC # A3: 2,8 => UNS
* INC # C3: 2,8 => UNS
* DIS # I7: 2,8 => CTR => I7: 3,9
* INC I7: 3,9 # I8: 2,8 => UNS
* INC I7: 3,9 # I8: 2,8 => UNS
* DIS I7: 3,9 # I8: 9 => CTR => I8: 2,8
* PRF I7: 3,9 + I8: 2,8 # A2: 2,8 => SOL
* STA I7: 3,9 + I8: 2,8 + A2: 2,8
* CNT   9 HDP CHAINS /   9 HYP OPENED