Analysis of xx-top500-350-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 69...2..........31...........314....2.....6.....3........71..4.86....5........... initial

Autosolve

position: 691.324.....6.493143.971.6.9.314672.214..7693..63291.43.971..4686.49351.14.26.3.9 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B2: 5,7 => SOL
* DIS # B2: 2 => CTR => B2: 5,7
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* DIS # I3: 2,8 => CTR => I3: 5
* PRF # I3: 5 => SOL
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* DIS # B6: 5,7 => CTR => B6: 8
* PRF # B6: 8 => SOL
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # B2: 2,5 => CTR => B2: 7
* PRF # B2: 7 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 5 => CTR => H1: 7,8
* CNT  30 HDP CHAINS /  30 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 # B2: 5,7 => SOL
* STA B2: 5,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

69...2..........31...........314....2.....6.....3........71..4.86....5........... initial
691.324.....6.493143.971.6.9.314672.214..7693..63291.43.971..4686.49351.14.26.3.9 autosolve
691532487572684931438971265953146728214857693786329154329715846867493512145268379 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
A2: 5,7
C3: 5,8
D1: 5,8
E2: 5,8
G3: 2,8
B4: 5,8
A6: 5,7
D5: 5,8
E5: 5,8
I4: 5,8
H6: 5,8
B7: 2,5
C8: 2,7
C9: 5,7
F7: 5,8
F9: 5,8
G7: 2,8
I8: 2,7
H9: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,C2: 2.. / B2 = 2  =>  0 pairs (X) / C2 = 2  =>  0 pairs (_)
G3,I3: 2.. / G3 = 2  =>  0 pairs (*) / I3 = 2  =>  0 pairs (X)
B7,C8: 2.. / B7 = 2  =>  0 pairs (*) / C8 = 2  =>  0 pairs (X)
G7,I8: 2.. / G7 = 2  =>  0 pairs (X) / I8 = 2  =>  0 pairs (_)
B7,G7: 2.. / B7 = 2  =>  0 pairs (*) / G7 = 2  =>  0 pairs (X)
C8,I8: 2.. / C8 = 2  =>  0 pairs (X) / I8 = 2  =>  0 pairs (_)
B2,B7: 2.. / B2 = 2  =>  0 pairs (X) / B7 = 2  =>  0 pairs (_)
C2,C8: 2.. / C2 = 2  =>  0 pairs (*) / C8 = 2  =>  0 pairs (X)
G3,G7: 2.. / G3 = 2  =>  0 pairs (*) / G7 = 2  =>  0 pairs (X)
I3,I8: 2.. / I3 = 2  =>  0 pairs (X) / I8 = 2  =>  0 pairs (_)
D1,E2: 5.. / D1 = 5  =>  0 pairs (*) / E2 = 5  =>  0 pairs (X)
D5,E5: 5.. / D5 = 5  =>  0 pairs (X) / E5 = 5  =>  0 pairs (_)
I4,H6: 5.. / I4 = 5  =>  0 pairs (X) / H6 = 5  =>  0 pairs (_)
B7,C9: 5.. / B7 = 5  =>  0 pairs (X) / C9 = 5  =>  0 pairs (_)
F7,F9: 5.. / F7 = 5  =>  0 pairs (*) / F9 = 5  =>  0 pairs (X)
C3,I3: 5.. / C3 = 5  =>  0 pairs (X) / I3 = 5  =>  0 pairs (_)
B4,I4: 5.. / B4 = 5  =>  0 pairs (*) / I4 = 5  =>  0 pairs (X)
B7,F7: 5.. / B7 = 5  =>  0 pairs (X) / F7 = 5  =>  0 pairs (_)
C9,F9: 5.. / C9 = 5  =>  0 pairs (*) / F9 = 5  =>  0 pairs (X)
A2,A6: 5.. / A2 = 5  =>  0 pairs (*) / A6 = 5  =>  0 pairs (X)
D1,D5: 5.. / D1 = 5  =>  0 pairs (*) / D5 = 5  =>  0 pairs (X)
E2,E5: 5.. / E2 = 5  =>  0 pairs (X) / E5 = 5  =>  0 pairs (_)
H1,H6: 5.. / H1 = 5  =>  0 pairs (X) / H6 = 5  =>  0 pairs (_)
A2,B2: 7.. / A2 = 7  =>  0 pairs (X) / B2 = 7  =>  0 pairs (_)
H1,I1: 7.. / H1 = 7  =>  0 pairs (X) / I1 = 7  =>  0 pairs (_)
A6,B6: 7.. / A6 = 7  =>  0 pairs (*) / B6 = 7  =>  0 pairs (X)
C8,C9: 7.. / C8 = 7  =>  0 pairs (*) / C9 = 7  =>  0 pairs (X)
I8,H9: 7.. / I8 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
C8,I8: 7.. / C8 = 7  =>  0 pairs (*) / I8 = 7  =>  0 pairs (X)
C9,H9: 7.. / C9 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
A2,A6: 7.. / A2 = 7  =>  0 pairs (X) / A6 = 7  =>  0 pairs (_)
B2,B6: 7.. / B2 = 7  =>  0 pairs (*) / B6 = 7  =>  0 pairs (X)
H1,H9: 7.. / H1 = 7  =>  0 pairs (X) / H9 = 7  =>  0 pairs (_)
I1,I8: 7.. / I1 = 7  =>  0 pairs (*) / I8 = 7  =>  0 pairs (X)
C2,C3: 8.. / C2 = 8  =>  0 pairs (X) / C3 = 8  =>  0 pairs (_)
D1,E2: 8.. / D1 = 8  =>  0 pairs (X) / E2 = 8  =>  0 pairs (_)
B4,B6: 8.. / B4 = 8  =>  0 pairs (X) / B6 = 8  =>  0 pairs (_)
D5,E5: 8.. / D5 = 8  =>  0 pairs (*) / E5 = 8  =>  0 pairs (X)
I4,H6: 8.. / I4 = 8  =>  0 pairs (*) / H6 = 8  =>  0 pairs (X)
F7,F9: 8.. / F7 = 8  =>  0 pairs (X) / F9 = 8  =>  0 pairs (_)
G7,H9: 8.. / G7 = 8  =>  0 pairs (*) / H9 = 8  =>  0 pairs (X)
C2,E2: 8.. / C2 = 8  =>  0 pairs (X) / E2 = 8  =>  0 pairs (_)
B4,I4: 8.. / B4 = 8  =>  0 pairs (X) / I4 = 8  =>  0 pairs (_)
B6,H6: 8.. / B6 = 8  =>  0 pairs (*) / H6 = 8  =>  0 pairs (X)
F7,G7: 8.. / F7 = 8  =>  0 pairs (X) / G7 = 8  =>  0 pairs (_)
F9,H9: 8.. / F9 = 8  =>  0 pairs (*) / H9 = 8  =>  0 pairs (X)
D1,D5: 8.. / D1 = 8  =>  0 pairs (X) / D5 = 8  =>  0 pairs (_)
E2,E5: 8.. / E2 = 8  =>  0 pairs (*) / E5 = 8  =>  0 pairs (X)
G3,G7: 8.. / G3 = 8  =>  0 pairs (X) / G7 = 8  =>  0 pairs (_)
* DURATION: 0:01:39.166938  START: 14:42:00.109950  END: 14:43:39.276888 2017-05-04
* CP COUNT: (49)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A6,B4,B7,C3,C8,C9,D1,D5,E2,E5,F7,F9,G3,G7,H6,H9,I4,I8)
* 691.324.....6.493143.971.6.9.314672.214..7693..63291.43.971..4686.49351.14.26.3.9
* PAIR A2: 5,7 BLK 1
B2: 5,7,2                                # reduction candidate for 5,7
B2: 5,7 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
B2: 2 => CTR
* 691.324..72.6.493143.971.6.9.314672.214..769357632918435971..4686.49351.14.26.3.9
* PAIR C3: 5,8 BLK 1
C2: 5,8,2                                # reduction candidate for 5,8
C2: 5,8 => CTR
* 691.324...2.6.493143.971.6.9.314672.214..7693.7632918435971..4686.49351.14.26.3.9
C2: 2 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR C3: 5,8 ROW 3
I3: 5,8,2                                # reduction candidate for 5,8
I3: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
I3: 2 => CTR
* 691.324.....6.49314359718629.3146728214..76935.63291.43.971..4686.49351.14.26.3.9
* PAIR D1: 5,8 ROW 1
H1: 5,8,7                                # reduction candidate for 5,8
H1: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
H1: 7 => CTR
* 691.3247.5726.493143.971.6.9.314672.214..7693..63291543.971..4686.493517147265389
I1: 5,8,7                                # reduction candidate for 5,8
I1: 5,8 => CTR
* 691.3247.5726.493143.971.6.9.314672.214..7693..63291543.971..4686.493517147265389
I1: 7 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR E2: 5,8 ROW 2
C2: 5,8,2                                # reduction candidate for 5,8
C2: 5,8 => CTR
* 691.324...2.6.493143.971.6.9.314672.214..7693.7632918435971..4686.49351.14.26.3.9
C2: 2 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR G3: 2,8 BLK 3
I3: 2,8,5                                # reduction candidate for 2,8
I3: 2,8 => CTR
* 691.324.....6.4931435971.6.9.314672.214..7693576329184359718.4686.49351.14.26.3.9
I3: 5 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR B4: 5,8 BLK 4
B6: 5,8,7                                # reduction candidate for 5,8
B6: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
B6: 7 => CTR
* 691.324577.26.493143.971.6.983146725214..76935763291843.971.84686.49351214.268379
* PAIR A6: 5,7 BLK 4
B6: 5,7,8                                # reduction candidate for 5,7
B6: 5,7 => CTR
* 691.32457..26.493143.971.6.983146725214..7693..63291843.971.84686.49351214.268379
B6: 8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR I4: 5,8 COL I
I1: 5,8,7                                # reduction candidate for 5,8
I1: 5,8 => CTR
* 691.3247.5726.493143.971.6.9.314672.214..7693..63291543.971..4686.493517147265389
I1: 7 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
I3: 5,8,2                                # reduction candidate for 5,8
I3: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
I3: 2 => CTR
* 691.324.....6.49314359718629.3146728214..76935.63291.43.971..4686.49351.14.26.3.9
* PAIR H6: 5,8 ROW 6
B6: 5,8,7                                # reduction candidate for 5,8
B6: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
B6: 7 => CTR
* 691.324577.26.493143.971.6.983146725214..76935763291843.971.84686.49351214.268379
* PAIR H6: 5,8 COL H
H1: 5,8,7                                # reduction candidate for 5,8
H1: 5,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
H1: 7 => CTR
* 691.3247.5726.493143.971.6.9.314672.214..7693..63291543.971..4686.493517147265389
* PAIR B7: 2,5 COL B
B2: 2,5,7                                # reduction candidate for 2,5
B2: 2,5 => CTR
* 691.324577.26.493143.971.6.9.314672.214..76935763291843.971.84686.49351214.268379
B2: 7 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* PAIR H9: 7,8 COL H
H1: 7,8,5                                # reduction candidate for 7,8
H1: 7,8 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
H1: 5 => CTR
* 691.32457...654931435971.6.9.3146725214587693576329184359718.4686.49351.14.26.3.9
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-350-base-pr-000.dot
* REASONING
* PRF # B2: 5,7 => SOL
* DIS # B2: 2 => CTR => B2: 5,7
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* DIS # I3: 2,8 => CTR => I3: 5
* PRF # I3: 5 => SOL
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* DIS # B6: 5,7 => CTR => B6: 8
* PRF # B6: 8 => SOL
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # B2: 2,5 => CTR => B2: 7
* PRF # B2: 7 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 5 => CTR => H1: 7,8
* CNT  30 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A6,B4,B7,C3,C8,C9,D1,D5,E2,E5,F7,F9,G3,G7,H6,H9,I4,I8)
* 691.324.....6.493143.971.6.9.314672.214..7693..63291.43.971..4686.49351.14.26.3.9
* PAIR A2: 5,7 BLK 1
B2: 5,7,2                                # reduction candidate for 5,7
B2: 5,7 => SOLVED
* 691532487572684931438971265953146728214857693786329154329715846867493512145268379
* DURATION: 0:00:02.179395  START: 14:44:19.605936  END: 14:44:21.785331 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-350-base-pr-001.dot
* REASONING
* PRF # B2: 5,7 => SOL
* STA B2: 5,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 350

solution: 691532487572684931438971265953146728214857693786329154329715846867493512145268379
info: 4882     FNBWY    S8.f     36162

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

Solution

position: 691532487572684931438971265953146728214857693786329154329715846867493512145268379 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 # B2: 5,7 => SOL
* DIS # B2: 2 => CTR => B2: 5,7
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* DIS # C2: 5,8 => CTR => C2: 2
* PRF # C2: 2 => SOL
* DIS # I3: 2,8 => CTR => I3: 5
* PRF # I3: 5 => SOL
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* DIS # B6: 5,7 => CTR => B6: 8
* PRF # B6: 8 => SOL
* DIS # I1: 5,8 => CTR => I1: 7
* PRF # I1: 7 => SOL
* PRF # I3: 5,8 => SOL
* DIS # I3: 2 => CTR => I3: 5,8
* PRF # B6: 5,8 => SOL
* DIS # B6: 7 => CTR => B6: 5,8
* PRF # H1: 5,8 => SOL
* DIS # H1: 7 => CTR => H1: 5,8
* DIS # B2: 2,5 => CTR => B2: 7
* PRF # B2: 7 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 5 => CTR => H1: 7,8
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # B2: 5,7 => SOL
* STA B2: 5,7
* CNT   1 HDP CHAINS /   1 HYP OPENED