Analysis of xx-top500-124-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...4.5.2..1.7......6....8....4....57....6....7............9.1.35..............6.. initial

Autosolve

position: ..7415926.1.786534465.2.8716.413.257.5.26741.721.5436..7659.1435..6417.214..7.6.5 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # A5: 3,8 => SOL
* DIS # A5: 9 => CTR => A5: 3,8
* DIS # B8: 3,8 => CTR => B8: 9
* PRF # B8: 9 => SOL
* PRF # C9: 8 => SOL
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* DIS # C9: 9 => CTR => C9: 2,8
* PRF # F9: 2,8 => SOL
* DIS # F9: 3 => CTR => F9: 2,8
* DIS # F9: 3,8 => CTR => F9: 2
* PRF # F9: 2 => SOL
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # C8: 8,9 => CTR => C8: 3
* PRF # C8: 3 => SOL
* PRF # C9: 8,9 => SOL
* DIS # C9: 2 => CTR => C9: 8,9
* CNT  26 HDP CHAINS /  28 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 # A5: 3,8 => SOL
* STA A5: 3,8
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

...4.5.2..1.7......6....8....4....57....6....7............9.1.35..............6.. initial
..7415926.1.786534465.2.8716.413.257.5.26741.721.5436..7659.1435..6417.214..7.6.5 autosolve
837415926912786534465923871684139257359267418721854369276598143593641782148372695 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
A1: 3,8
B1: 3,8
A2: 2,9
C2: 2,9
D3: 3,9
F3: 3,9
B4: 8,9
F4: 8,9
D6: 8,9
I5: 8,9
I6: 8,9
A7: 2,8
F7: 2,8
D9: 3,8
H8: 8,9
H9: 8,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,C2: 2.. / A2 = 2  =>  0 pairs (X) / C2 = 2  =>  0 pairs (_)
A7,C9: 2.. / A7 = 2  =>  0 pairs (*) / C9 = 2  =>  0 pairs (X)
F7,F9: 2.. / F7 = 2  =>  0 pairs (X) / F9 = 2  =>  0 pairs (_)
A7,F7: 2.. / A7 = 2  =>  0 pairs (*) / F7 = 2  =>  0 pairs (X)
C9,F9: 2.. / C9 = 2  =>  0 pairs (X) / F9 = 2  =>  0 pairs (_)
A2,A7: 2.. / A2 = 2  =>  0 pairs (X) / A7 = 2  =>  0 pairs (_)
C2,C9: 2.. / C2 = 2  =>  0 pairs (*) / C9 = 2  =>  0 pairs (X)
A1,B1: 3.. / A1 = 3  =>  0 pairs (X) / B1 = 3  =>  0 pairs (_)
D3,F3: 3.. / D3 = 3  =>  0 pairs (X) / F3 = 3  =>  0 pairs (_)
A5,C5: 3.. / A5 = 3  =>  0 pairs (*) / C5 = 3  =>  0 pairs (X)
B8,C8: 3.. / B8 = 3  =>  0 pairs (X) / C8 = 3  =>  0 pairs (_)
D9,F9: 3.. / D9 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
A1,A5: 3.. / A1 = 3  =>  0 pairs (X) / A5 = 3  =>  0 pairs (_)
B1,B8: 3.. / B1 = 3  =>  0 pairs (*) / B8 = 3  =>  0 pairs (X)
C5,C8: 3.. / C5 = 3  =>  0 pairs (X) / C8 = 3  =>  0 pairs (_)
D3,D9: 3.. / D3 = 3  =>  0 pairs (X) / D9 = 3  =>  0 pairs (_)
F3,F9: 3.. / F3 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
A1,B1: 8.. / A1 = 8  =>  0 pairs (*) / B1 = 8  =>  0 pairs (X)
F4,D6: 8.. / F4 = 8  =>  0 pairs (X) / D6 = 8  =>  0 pairs (_)
I5,I6: 8.. / I5 = 8  =>  0 pairs (*) / I6 = 8  =>  0 pairs (X)
H8,H9: 8.. / H8 = 8  => 17 pairs (_) / H9 = 8  =>  0 pairs (X)
B4,F4: 8.. / B4 = 8  =>  0 pairs (*) / F4 = 8  =>  0 pairs (X)
D6,I6: 8.. / D6 = 8  =>  0 pairs (*) / I6 = 8  =>  0 pairs (X)
A7,F7: 8.. / A7 = 8  =>  0 pairs (X) / F7 = 8  =>  0 pairs (_)
D6,D9: 8.. / D6 = 8  =>  0 pairs (*) / D9 = 8  =>  0 pairs (X)
A2,C2: 9.. / A2 = 9  =>  0 pairs (*) / C2 = 9  =>  0 pairs (X)
D3,F3: 9.. / D3 = 9  =>  0 pairs (*) / F3 = 9  =>  0 pairs (X)
F4,D6: 9.. / F4 = 9  =>  0 pairs (*) / D6 = 9  =>  0 pairs (X)
I5,I6: 9.. / I5 = 9  =>  0 pairs (X) / I6 = 9  =>  0 pairs (_)
H8,H9: 9.. / H8 = 9  =>  0 pairs (X) / H9 = 9  => 17 pairs (_)
B4,F4: 9.. / B4 = 9  =>  0 pairs (X) / F4 = 9  =>  0 pairs (_)
D6,I6: 9.. / D6 = 9  =>  0 pairs (X) / I6 = 9  =>  0 pairs (_)
C9,H9: 9.. / C9 = 9  =>  0 pairs (X) / H9 = 9  => 17 pairs (_)
A2,A5: 9.. / A2 = 9  =>  0 pairs (*) / A5 = 9  =>  0 pairs (X)
B4,B8: 9.. / B4 = 9  =>  0 pairs (X) / B8 = 9  =>  0 pairs (_)
D3,D6: 9.. / D3 = 9  =>  0 pairs (*) / D6 = 9  =>  0 pairs (X)
F3,F4: 9.. / F3 = 9  =>  0 pairs (X) / F4 = 9  =>  0 pairs (_)
* DURATION: 0:01:01.900397  START: 07:00:16.218130  END: 07:01:18.118527 2017-05-04
* CP COUNT: (37)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,A7,B1,B4,C2,D3,D6,D9,F3,F4,F7,H8,H9,I5,I6)
* ..7415926.1.786534465.2.8716.413.257.5.26741.721.5436..7659.1435..6417.214..7.6.5
* PAIR A1: 3,8 COL A
A5: 3,8,9                                # reduction candidate for 3,8
A5: 3,8 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
A5: 9 => CTR
* 387415926.1.786534465.2.87169413.257.5.26741.721.5436..7659.1435..6417.214..7.6.5
* PAIR B1: 3,8 COL B
B8: 3,8,9                                # reduction candidate for 3,8
B8: 3,8 => CTR
* ..7415926.1.786534465.2.871694138257.5.2674197219543688765921435396417.214..7.6.5
B8: 9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
* PAIR C2: 2,9 COL C
C9: 2,9,8                                # reduction candidate for 2,9
C9: 8 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C9: 2,9                                  # 19 pairs
* PAIR B4: 8,9 BLK 4
A5: 8,9,3                                # reduction candidate for 8,9
A5: 8,9 => CTR
* 387415926.1.786534465.2.87169413825785326741972195436827659.1435..6417.214..7.6.5
A5: 3 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C5: 8,9,3                                # reduction candidate for 8,9
C5: 8,9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C5: 3 => CTR
* 387415926.1.786534465.2.87169413825785326741972195436827659.14353.6417.214..7.6.5
* PAIR B4: 8,9 COL B
B8: 8,9,3                                # reduction candidate for 8,9
B8: 8,9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
B8: 3 => CTR
* ..7415926.1.786534465.2.871694138257.5.2674197219543688765921435396417.214..7.6.5
* PAIR I5: 8,9 ROW 5
A5: 8,9,3                                # reduction candidate for 8,9
A5: 8,9 => CTR
* 387415926.1.786534465.2.87169413825785326741972195436827659.1435..6417.214..7.6.5
A5: 3 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C5: 8,9,3                                # reduction candidate for 8,9
C5: 8,9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C5: 3 => CTR
* 387415926.1.786534465.2.87169413825785326741972195436827659.14353.6417.214..7.6.5
* PAIR A7: 2,8 BLK 7
C9: 2,8,9                                # reduction candidate for 2,8
C9: 9 => CTR
* ..7415926.12786534465.2.8716.413.257.5.26741.721.5436.2765981435..6417.2149372685
C9: 2,8                                  # 17 pairs
* PAIR F7: 2,8 BLK 8
F9: 2,8,3                                # reduction candidate for 2,8
F9: 2,8 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
F9: 3 => CTR
* ..7415926219786534465329871694138257.5.26741972195436887659214353.6417.2142873695
* PAIR D9: 3,8 BLK 8
F9: 3,8,2                                # reduction candidate for 3,8
F9: 3,8 => CTR
* ..7415926219786534465.2.8716.413.2579532674187218543698765921435..6417.2142.7.695
F9: 2 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
* PAIR H8: 8,9 ROW 8
B8: 8,9,3                                # reduction candidate for 8,9
B8: 8,9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
B8: 3 => CTR
* ..7415926.1.786534465.2.871694138257.5.2674197219543688765921435396417.214..7.6.5
C8: 8,9,3                                # reduction candidate for 8,9
C8: 8,9 => CTR
* 387415926.1.786534465.2.87169413825785326741972195436827659.14353.6417.214..7.6.5
C8: 3 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
* PAIR H9: 8,9 ROW 9
C9: 8,9,2                                # reduction candidate for 8,9
C9: 8,9 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
C9: 2 => CTR
* ..7415926219786534465.2.8716.413.25795326741872185436987659.1435..6417.2142.7.695
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-124-base-pr-000.dot
* REASONING
* PRF # A5: 3,8 => SOL
* DIS # A5: 9 => CTR => A5: 3,8
* DIS # B8: 3,8 => CTR => B8: 9
* PRF # B8: 9 => SOL
* PRF # C9: 8 => SOL
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* DIS # C9: 9 => CTR => C9: 2,8
* PRF # F9: 2,8 => SOL
* DIS # F9: 3 => CTR => F9: 2,8
* DIS # F9: 3,8 => CTR => F9: 2
* PRF # F9: 2 => SOL
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # C8: 8,9 => CTR => C8: 3
* PRF # C8: 3 => SOL
* PRF # C9: 8,9 => SOL
* DIS # C9: 2 => CTR => C9: 8,9
* CNT  26 HDP CHAINS /  28 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,A7,B1,B4,C2,D3,D6,D9,F3,F4,F7,H8,H9,I5,I6)
* ..7415926.1.786534465.2.8716.413.257.5.26741.721.5436..7659.1435..6417.214..7.6.5
* PAIR A1: 3,8 COL A
A5: 3,8,9                                # reduction candidate for 3,8
A5: 3,8 => SOLVED
* 837415926912786534465923871684139257359267418721854369276598143593641782148372695
* DURATION: 0:00:01.868742  START: 07:01:50.115721  END: 07:01:51.984463 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-124-base-pr-001.dot
* REASONING
* PRF # A5: 3,8 => SOL
* STA A5: 3,8
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 124

solution: 837415926912786534465923871684139257359267418721854369276598143593641782148372695
info: 1808     FNBWY    S8.f     9308

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

Solution

position: 837415926912786534465923871684139257359267418721854369276598143593641782148372695 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 # A5: 3,8 => SOL
* DIS # A5: 9 => CTR => A5: 3,8
* DIS # B8: 3,8 => CTR => B8: 9
* PRF # B8: 9 => SOL
* INC # C9: 2,9 => UNS
* PRF # C9: 8 => SOL
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # A5: 8,9 => CTR => A5: 3
* PRF # A5: 3 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 3 => CTR => C5: 8,9
* INC # C9: 2,8 => UNS
* DIS # C9: 9 => CTR => C9: 2,8
* PRF # F9: 2,8 => SOL
* DIS # F9: 3 => CTR => F9: 2,8
* DIS # F9: 3,8 => CTR => F9: 2
* PRF # F9: 2 => SOL
* PRF # B8: 8,9 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # C8: 8,9 => CTR => C8: 3
* PRF # C8: 3 => SOL
* PRF # C9: 8,9 => SOL
* DIS # C9: 2 => CTR => C9: 8,9
* CNT  28 HDP CHAINS /  28 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # A5: 3,8 => SOL
* STA A5: 3,8
* CNT   1 HDP CHAINS /   1 HYP OPENED