Analysis of xx-top500-146-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .21..........4...5..........3.1.6...7......4....2.....4.....1.75...8..........23. initial

Autosolve

position: .21.6....3.7.42.15.45.1..2.23417658971.....42.582.4..1483629157572381...1..457238 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # A3: 8,9 => SOL
* DIS # A3: 6 => CTR => A3: 8,9
* DIS # D1: 8,9 => CTR => D1: 5,7
* DIS # G1: 8,9 => CTR => G1: 4,7
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # G2: 6,9 => CTR => G2: 8
* PRF # G2: 8 => SOL
* DIS # D1: 8,9 => CTR => D1: 5,7
* PRF # D3: 8,9 => SOL
* PRF # G2: 8,9 => SOL
* DIS # G2: 6 => CTR => G2: 8,9
* DIS # F1: 3,8 => CTR => F1: 5
* PRF # F1: 5 => SOL
* DIS # G1: 7,9 => CTR => G1: 4,8
* PRF # D1: 7,9 => SOL
* DIS # D1: 5,8 => CTR => D1: 7,9
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # D1: 5,8 => CTR => D1: 7,9
* PRF # D1: 7,9 => SOL
* PRF # F1: 5,8 => SOL
* DIS # F1: 3 => CTR => F1: 5,8
* PRF # G6: 3,6 => SOL
* DIS # G6: 7 => CTR => G6: 3,6
* DIS # G6: 6,7 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G8: 6,9 => SOL
* DIS # G8: 4 => CTR => G8: 6,9
* DIS # G8: 4,6 => CTR => G8: 9
* PRF # G8: 9 => SOL
* CNT  29 HDP CHAINS /  37 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 # A3: 8,9 => SOL
* STA A3: 8,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.21..........4...5..........3.1.6...7......4....2.....4.....1.75...8..........23. initial
.21.6....3.7.42.15.45.1..2.23417658971.....42.582.4..1483629157572381...1..457238 autosolve
821765493367942815945813726234176589719538642658294371483629157572381964196457238 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
A1: 8,9
B2: 6,9
D2: 8,9
F3: 3,8
H1: 7,9
I1: 3,4
I3: 3,6
C5: 6,9
A6: 6,9
D5: 5,8
E5: 3,9
F5: 5,8
E6: 3,9
G5: 3,6
H6: 6,7
B9: 6,9
C9: 6,9
H8: 6,9
I8: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F1,F3: 3.. / F1 = 3  =>  0 pairs (X) / F3 = 3  =>  0 pairs (_)
I1,I3: 3.. / I1 = 3  =>  0 pairs (*) / I3 = 3  =>  0 pairs (X)
E5,E6: 3.. / E5 = 3  =>  0 pairs (*) / E6 = 3  =>  0 pairs (X)
G5,G6: 3.. / G5 = 3  =>  0 pairs (X) / G6 = 3  =>  0 pairs (_)
F1,I1: 3.. / F1 = 3  =>  0 pairs (X) / I1 = 3  =>  0 pairs (_)
F3,I3: 3.. / F3 = 3  =>  0 pairs (*) / I3 = 3  =>  0 pairs (X)
E5,G5: 3.. / E5 = 3  =>  0 pairs (*) / G5 = 3  =>  0 pairs (X)
E6,G6: 3.. / E6 = 3  =>  0 pairs (X) / G6 = 3  =>  0 pairs (_)
G1,I1: 4.. / G1 = 4  =>  0 pairs (*) / I1 = 4  =>  0 pairs (X)
G8,I8: 4.. / G8 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
G1,G8: 4.. / G1 = 4  =>  0 pairs (*) / G8 = 4  =>  0 pairs (X)
I1,I8: 4.. / I1 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
D1,F1: 5.. / D1 = 5  =>  0 pairs (X) / F1 = 5  =>  0 pairs (_)
D5,F5: 5.. / D5 = 5  =>  0 pairs (*) / F5 = 5  =>  0 pairs (X)
D1,D5: 5.. / D1 = 5  =>  0 pairs (X) / D5 = 5  =>  0 pairs (_)
F1,F5: 5.. / F1 = 5  =>  0 pairs (*) / F5 = 5  =>  0 pairs (X)
B2,A3: 6.. / B2 = 6  =>  0 pairs (*) / A3 = 6  =>  0 pairs (X)
C5,A6: 6.. / C5 = 6  =>  0 pairs (X) / A6 = 6  =>  0 pairs (_)
B9,C9: 6.. / B9 = 6  =>  0 pairs (X) / C9 = 6  =>  0 pairs (_)
B2,G2: 6.. / B2 = 6  =>  0 pairs (*) / G2 = 6  =>  0 pairs (X)
C5,G5: 6.. / C5 = 6  =>  0 pairs (X) / G5 = 6  =>  0 pairs (_)
A3,A6: 6.. / A3 = 6  =>  0 pairs (X) / A6 = 6  =>  0 pairs (_)
B2,B9: 6.. / B2 = 6  =>  0 pairs (*) / B9 = 6  =>  0 pairs (X)
C5,C9: 6.. / C5 = 6  =>  0 pairs (X) / C9 = 6  =>  0 pairs (_)
H6,H8: 6.. / H6 = 6  =>  0 pairs (X) / H8 = 6  =>  0 pairs (_)
I3,I8: 6.. / I3 = 6  =>  0 pairs (*) / I8 = 6  =>  0 pairs (X)
D1,D3: 7.. / D1 = 7  =>  0 pairs (*) / D3 = 7  =>  0 pairs (X)
G6,H6: 7.. / G6 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
D3,G3: 7.. / D3 = 7  => 19 pairs (_) / G3 = 7  =>  0 pairs (*)
H1,H6: 7.. / H1 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
A1,A3: 8.. / A1 = 8  => 20 pairs (_) / A3 = 8  =>  0 pairs (X)
D5,F5: 8.. / D5 = 8  =>  0 pairs (X) / F5 = 8  =>  0 pairs (_)
D2,G2: 8.. / D2 = 8  =>  0 pairs (X) / G2 = 8  =>  0 pairs (_)
C5,A6: 9.. / C5 = 9  =>  0 pairs (*) / A6 = 9  =>  0 pairs (X)
E5,E6: 9.. / E5 = 9  =>  0 pairs (X) / E6 = 9  =>  0 pairs (_)
B9,C9: 9.. / B9 = 9  =>  0 pairs (*) / C9 = 9  =>  0 pairs (X)
G8,H8: 9.. / G8 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
C5,E5: 9.. / C5 = 9  =>  0 pairs (*) / E5 = 9  =>  0 pairs (X)
A6,E6: 9.. / A6 = 9  =>  0 pairs (X) / E6 = 9  =>  0 pairs (_)
B2,B9: 9.. / B2 = 9  =>  0 pairs (X) / B9 = 9  =>  0 pairs (_)
C5,C9: 9.. / C5 = 9  =>  0 pairs (*) / C9 = 9  =>  0 pairs (X)
H1,H8: 9.. / H1 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
* DURATION: 0:01:18.388178  START: 07:43:54.320698  END: 07:45:12.708876 2017-05-04
* CP COUNT: (42)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B2,B9,C5,C9,D2,D5,E5,E6,F3,F5,G5,H1,H6,H8,I1,I3,I8)
* .21.6....3.7.42.15.45.1..2.23417658971.....42.582.4..1483629157572381...1..457238
* PAIR A1: 8,9 BLK 1
A3: 8,9,6                                # reduction candidate for 8,9
A3: 8,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
A3: 6 => CTR
* 821.6....397842615645.13.2.23417658971.....42.582.4..1483629157572381...1..457238
* PAIR A1: 8,9 ROW 1
D1: 8,9,5,7                              # reduction candidate for 8,9
D1: 8,9 => CTR
* .21.65..33.7.42.15.45713.2623417658971.5.8.42658294371483629157572381.641.6457238
D1: 5,7                                  # 20 pairs
G1: 8,9,4,7                              # reduction candidate for 8,9
G1: 8,9 => CTR
* 8215639743.7942815.45718.2323417658971.8.5.42.582.47614836291575723814961..457238
G1: 4,7                                  # 20 pairs
* PAIR B2: 6,9 BLK 1
A3: 6,9,8                                # reduction candidate for 6,9
A3: 8 => CTR
* .21.6....367.42.15845.13.2623417658971.....42658294371483629157572381.64196457238
A3: 6,9                                  # 20 pairs
* PAIR B2: 6,9 ROW 2
G2: 6,9,8                                # reduction candidate for 6,9
G2: 6,9 => CTR
* .21.6....3.7842.15.45.13.2623417658971.5.8.42658294371483629157572381.641.6457238
G2: 8 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* PAIR D2: 8,9 BLK 2
D1: 8,9,5,7                              # reduction candidate for 8,9
D1: 8,9 => CTR
* .21.65..33.7.42.15.45713.2623417658971.5.8.42658294371483629157572381.641.6457238
D1: 5,7                                  # 20 pairs
D3: 8,9,7                                # reduction candidate for 8,9
D3: 8,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
D3: 7                                    # 19 pairs
* PAIR D2: 8,9 ROW 2
G2: 8,9,6                                # reduction candidate for 8,9
G2: 8,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
G2: 6 => CTR
* .21.6....3.7842615645.13.2.23417658971.....42.582.4..1483629157572381...1..457238
* PAIR F3: 3,8 BLK 2
F1: 3,8,5                                # reduction candidate for 3,8
F1: 3,8 => CTR
* .2156....367942815.4571..2.234176589719835642658294371483629157572381.64196457238
F1: 5 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* PAIR H1: 7,9 BLK 3
G1: 7,9,4,8                              # reduction candidate for 7,9
G1: 7,9 => CTR
* 8215639743.7942815.45718.2323417658971.8.5.42.582.47614836291575723814961..457238
G1: 4,8                                  # 20 pairs
G3: 7,9,6,8                              # reduction candidate for 7,9
G3: 7,9                                  # 22 pairs
* PAIR H1: 7,9 ROW 1
D1: 7,9,5,8                              # reduction candidate for 7,9
D1: 7,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
D1: 5,8 => CTR
* .21.6....367942815.4571..2.234176589719.3.642658294371483629157572381.64196457238
* PAIR A6: 6,9 COL A
A3: 6,9,8                                # reduction candidate for 6,9
A3: 8 => CTR
* .21.6....367.42.15845.13.2623417658971.....42658294371483629157572381.64196457238
A3: 6,9                                  # 20 pairs
* PAIR D5: 5,8 COL D
D1: 5,8,7,9                              # reduction candidate for 5,8
D1: 5,8 => CTR
* .21.6....367942815.4571..2.234176589719.3.642658294371483629157572381.64196457238
D1: 7,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* PAIR F5: 5,8 COL F
F1: 5,8,3                                # reduction candidate for 5,8
F1: 5,8 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
F1: 3 => CTR
* 8215639743.794281594571862323417658971.8.5.42.582.4..14836291575723814961..457238
* PAIR G5: 3,6 BLK 6
G6: 3,6,7                                # reduction candidate for 3,6
G6: 3,6 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
G6: 7 => CTR
* 82196..7.3.7.42.1564571.923234176589716.9.342958234761483629157572381.96169457238
* PAIR H6: 6,7 BLK 6
G6: 6,7,3                                # reduction candidate for 6,7
G6: 6,7 => CTR
* 821.6....397842615645.13.2.234176589716.9.342958234..1483629157572381...169457238
G6: 3 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* PAIR H8: 6,9 BLK 9
G8: 6,9,4                                # reduction candidate for 6,9
G8: 6,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
G8: 4 => CTR
* .21.63.743.7.42.1564571892323417658971.....42.582.47614836291575723814961..457238
* PAIR I8: 4,6 BLK 9
G8: 4,6,9                                # reduction candidate for 4,6
G8: 4,6 => CTR
* 82196..7.3.7.42.1564571.923234176589716.9.342958234761483629157572381.96169457238
G8: 9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-146-base-pr-000.dot
* REASONING
* PRF # A3: 8,9 => SOL
* DIS # A3: 6 => CTR => A3: 8,9
* DIS # D1: 8,9 => CTR => D1: 5,7
* DIS # G1: 8,9 => CTR => G1: 4,7
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # G2: 6,9 => CTR => G2: 8
* PRF # G2: 8 => SOL
* DIS # D1: 8,9 => CTR => D1: 5,7
* PRF # D3: 8,9 => SOL
* PRF # G2: 8,9 => SOL
* DIS # G2: 6 => CTR => G2: 8,9
* DIS # F1: 3,8 => CTR => F1: 5
* PRF # F1: 5 => SOL
* DIS # G1: 7,9 => CTR => G1: 4,8
* PRF # D1: 7,9 => SOL
* DIS # D1: 5,8 => CTR => D1: 7,9
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # D1: 5,8 => CTR => D1: 7,9
* PRF # D1: 7,9 => SOL
* PRF # F1: 5,8 => SOL
* DIS # F1: 3 => CTR => F1: 5,8
* PRF # G6: 3,6 => SOL
* DIS # G6: 7 => CTR => G6: 3,6
* DIS # G6: 6,7 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G8: 6,9 => SOL
* DIS # G8: 4 => CTR => G8: 6,9
* DIS # G8: 4,6 => CTR => G8: 9
* PRF # G8: 9 => SOL
* CNT  29 HDP CHAINS /  37 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,B2,B9,C5,C9,D2,D5,E5,E6,F3,F5,G5,H1,H6,H8,I1,I3,I8)
* .21.6....3.7.42.15.45.1..2.23417658971.....42.582.4..1483629157572381...1..457238
* PAIR A1: 8,9 BLK 1
A3: 8,9,6                                # reduction candidate for 8,9
A3: 8,9 => SOLVED
* 821765493367942815945813726234176589719538642658294371483629157572381964196457238
* DURATION: 0:00:02.179676  START: 07:45:58.593143  END: 07:46:00.772819 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-146-base-pr-001.dot
* REASONING
* PRF # A3: 8,9 => SOL
* STA A3: 8,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 146

solution: 821765493367942815945813726234176589719538642658294371483629157572381964196457238
info: 1815     FNBWY    S8.f     16992

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

Solution

position: 821765493367942815945813726234176589719538642658294371483629157572381964196457238 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 # A3: 8,9 => SOL
* DIS # A3: 6 => CTR => A3: 8,9
* DIS # D1: 8,9 => CTR => D1: 5,7
* INC # D1: 5,7 => UNS
* DIS # G1: 8,9 => CTR => G1: 4,7
* INC # G1: 4,7 => UNS
* INC # A3: 6,9 => UNS
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # G2: 6,9 => CTR => G2: 8
* PRF # G2: 8 => SOL
* DIS # D1: 8,9 => CTR => D1: 5,7
* INC # D1: 5,7 => UNS
* PRF # D3: 8,9 => SOL
* INC # D3: 7 => UNS
* PRF # G2: 8,9 => SOL
* DIS # G2: 6 => CTR => G2: 8,9
* DIS # F1: 3,8 => CTR => F1: 5
* PRF # F1: 5 => SOL
* DIS # G1: 7,9 => CTR => G1: 4,8
* INC # G1: 4,8 => UNS
* INC # G3: 7,9 => UNS
* PRF # D1: 7,9 => SOL
* DIS # D1: 5,8 => CTR => D1: 7,9
* INC # A3: 6,9 => UNS
* DIS # A3: 8 => CTR => A3: 6,9
* DIS # D1: 5,8 => CTR => D1: 7,9
* PRF # D1: 7,9 => SOL
* PRF # F1: 5,8 => SOL
* DIS # F1: 3 => CTR => F1: 5,8
* PRF # G6: 3,6 => SOL
* DIS # G6: 7 => CTR => G6: 3,6
* DIS # G6: 6,7 => CTR => G6: 3
* PRF # G6: 3 => SOL
* PRF # G8: 6,9 => SOL
* DIS # G8: 4 => CTR => G8: 6,9
* DIS # G8: 4,6 => CTR => G8: 9
* PRF # G8: 9 => SOL
* CNT  37 HDP CHAINS /  37 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # A3: 8,9 => SOL
* STA A3: 8,9
* CNT   1 HDP CHAINS /   1 HYP OPENED