Analysis of xx-top500-289-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6..2.8.3...7...1.4........5..5.1........4...........2.28.3...........7...3....... initial

Autosolve

position: 6..258937527.3.184398.7.265..5.123....2.43.....3.8..2.28.397....5682.793739.658.2 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B6: 1,4 => CTR => B6: 6,7
* DIS # D5: 6,9 => CTR => D5: 5,7
* DIS # D6: 6,9 => CTR => D6: 5,7
* DIS # D5: 6,9 => CTR => D5: 5,7
* DIS # D6: 6,9 => CTR => D6: 5,7
* DIS # G6: 5,6 => CTR => G6: 4
* DIS # G7: 4 => CTR => G7: 5,6
* PRF # H7: 1,4 => SOL
* DIS # I5: 1,6 => CTR => I5: 8,9
* PRF # H7: 1,4 => SOL
* CNT  10 HDP CHAINS /  31 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 # B6: 1,4 => CTR => B6: 6,7
* DIS B6: 6,7 # D5: 6,9 => CTR => D5: 5,7
* DIS B6: 6,7 + D5: 5,7 # D6: 6,9 => CTR => D6: 5,7
* DIS B6: 6,7 + D5: 5,7 + D6: 5,7 # I6: 6,9 => CTR => I6: 1
* PRF B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1 => SOL
* STA B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1
* CNT   5 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

6..2.8.3...7...1.4........5..5.1........4...........2.28.3...........7...3....... initial
6..258937527.3.184398.7.265..5.123....2.43.....3.8..2.28.397....5682.793739.658.2 autosolve
641258937527639184398471265465912378812743659973586421284397516156824793739165842 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
B1: 1,4
C1: 1,4
D2: 6,9
F2: 6,9
D3: 1,4
F3: 1,4
F6: 6,9
H4: 4,7
G5: 5,6
C7: 1,4
A8: 1,4
F8: 1,4
D9: 1,4
I7: 1,6
H9: 1,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B1,C1: 1.. / B1 = 1  =>  0 pairs (X) / C1 = 1  =>  0 pairs (_)
D3,F3: 1.. / D3 = 1  =>  0 pairs (X) / F3 = 1  =>  0 pairs (_)
C7,A8: 1.. / C7 = 1  =>  0 pairs (X) / A8 = 1  =>  0 pairs (_)
F8,D9: 1.. / F8 = 1  =>  0 pairs (X) / D9 = 1  =>  0 pairs (_)
A8,F8: 1.. / A8 = 1  =>  0 pairs (*) / F8 = 1  =>  0 pairs (X)
D9,H9: 1.. / D9 = 1  =>  0 pairs (*) / H9 = 1  =>  0 pairs (X)
C1,C7: 1.. / C1 = 1  =>  0 pairs (*) / C7 = 1  =>  0 pairs (X)
D3,D9: 1.. / D3 = 1  =>  0 pairs (X) / D9 = 1  =>  0 pairs (_)
F3,F8: 1.. / F3 = 1  =>  0 pairs (*) / F8 = 1  =>  0 pairs (X)
B1,C1: 4.. / B1 = 4  =>  0 pairs (*) / C1 = 4  =>  0 pairs (X)
D3,F3: 4.. / D3 = 4  =>  0 pairs (*) / F3 = 4  =>  0 pairs (X)
H4,G6: 4.. / H4 = 4  =>  0 pairs (X) / G6 = 4  => 22 pairs (_)
C7,A8: 4.. / C7 = 4  =>  0 pairs (*) / A8 = 4  =>  0 pairs (X)
F8,D9: 4.. / F8 = 4  =>  0 pairs (*) / D9 = 4  =>  0 pairs (X)
A8,F8: 4.. / A8 = 4  =>  0 pairs (X) / F8 = 4  =>  0 pairs (_)
D9,H9: 4.. / D9 = 4  =>  0 pairs (X) / H9 = 4  =>  0 pairs (_)
C1,C7: 4.. / C1 = 4  =>  0 pairs (X) / C7 = 4  =>  0 pairs (_)
D3,D9: 4.. / D3 = 4  =>  0 pairs (*) / D9 = 4  =>  0 pairs (X)
F3,F8: 4.. / F3 = 4  =>  0 pairs (X) / F8 = 4  =>  0 pairs (_)
G6,G7: 4.. / G6 = 4  => 22 pairs (_) / G7 = 4  =>  0 pairs (X)
D5,D6: 5.. / D5 = 5  =>  0 pairs (X) / D6 = 5  => 18 pairs (_)
G7,H7: 5.. / G7 = 5  =>  0 pairs (*) / H7 = 5  =>  0 pairs (X)
D6,G6: 5.. / D6 = 5  => 18 pairs (_) / G6 = 5  =>  0 pairs (X)
H5,H7: 5.. / H5 = 5  =>  0 pairs (*) / H7 = 5  =>  0 pairs (X)
D2,F2: 6.. / D2 = 6  => 15 pairs (_) / F2 = 6  => 19 pairs (_)
G7,I7: 6.. / G7 = 6  =>  0 pairs (X) / I7 = 6  => 18 pairs (_)
F2,F6: 6.. / F2 = 6  => 19 pairs (_) / F6 = 6  => 15 pairs (_)
H4,H5: 7.. / H4 = 7  => 22 pairs (_) / H5 = 7  =>  0 pairs (X)
B6,D6: 7.. / B6 = 7  => 17 pairs (_) / D6 = 7  =>  0 pairs (X)
A4,A5: 8.. / A4 = 8  => 17 pairs (_) / A5 = 8  => 16 pairs (_)
I4,I5: 8.. / I4 = 8  => 16 pairs (_) / I5 = 8  => 17 pairs (_)
A4,I4: 8.. / A4 = 8  => 17 pairs (_) / I4 = 8  => 16 pairs (_)
A5,I5: 8.. / A5 = 8  => 16 pairs (_) / I5 = 8  => 17 pairs (_)
D2,F2: 9.. / D2 = 9  => 19 pairs (_) / F2 = 9  => 15 pairs (_)
F2,F6: 9.. / F2 = 9  => 15 pairs (_) / F6 = 9  => 19 pairs (_)
* DURATION: 0:01:05.821048  START: 12:49:37.607350  END: 12:50:43.428398 2017-05-04
* CP COUNT: (35)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B1,C1,C7,D2,D3,D9,F2,F3,F6,F8,G5,H4,H9,I7)
* 6..258937527.3.184398.7.265..5.123....2.43.....3.8..2.28.397....5682.793739.658.2
* PAIR B1: 1,4 COL B
B6: 1,4,6,7                              # reduction candidate for 1,4
B6: 1,4 => CTR
* 6.4258937527.3.184398174265..5.1234...254367..4378.52.28.397456456821793739465812
B6: 6,7                                  # 16 pairs
* PAIR D2: 6,9 COL D
D4: 6,9,7                                # reduction candidate for 6,9
D4: 6,9                                  # 20 pairs
D5: 6,9,5,7                              # reduction candidate for 6,9
D5: 6,9 => CTR
* 6..258937527.3.184398.7.265..571234...2.43.7..7358.62.28.397456456821793739465812
D5: 5,7                                  # 18 pairs
D6: 6,9,5,7                              # reduction candidate for 6,9
D6: 6,9 => CTR
* 6..258937527.3.184398.7.265..5.123....25436...73.8.52.28.397456456821793739465812
D6: 5,7                                  # 16 pairs
* PAIR F6: 6,9 BLK 5
D4: 6,9,7                                # reduction candidate for 6,9
D4: 6,9                                  # 20 pairs
D5: 6,9,5,7                              # reduction candidate for 6,9
D5: 6,9 => CTR
* 6..258937527.3.184398.7.265..571234...2.43.7..7358.62.28.397456456821793739465812
D5: 5,7                                  # 18 pairs
D6: 6,9,5,7                              # reduction candidate for 6,9
D6: 6,9 => CTR
* 6..258937527.3.184398.7.265..5.123....25436...73.8.52.28.397456456821793739465812
D6: 5,7                                  # 16 pairs
* PAIR F6: 6,9 ROW 6
I6: 6,9,1                                # reduction candidate for 6,9
I6: 6,9                                  # 22 pairs
I6: 1                                    # 19 pairs
* PAIR H4: 4,7 ROW 4
B4: 4,7,6                                # reduction candidate for 4,7
B4: 4,7                                  # 23 pairs
B4: 6                                    # 18 pairs
* PAIR G5: 5,6 BLK 6
G6: 5,6,4                                # reduction candidate for 5,6
G6: 5,6 => CTR
* 614258937527.3.184398174265.7561234..62.43.7..4378.52.281397456456821793739465812
G6: 4                                    # 22 pairs
* PAIR G5: 5,6 ROW 5
D5: 5,6,7,9                              # reduction candidate for 5,6
D5: 5,6                                  # 21 pairs
D5: 7,9                                  # 19 pairs
* PAIR G5: 5,6 COL G
G7: 5,6,4                                # reduction candidate for 5,6
G7: 4 => CTR
* 614258937527.3.184398174265.7561234..62.43.7..4378.52.281397456456821793739465812
G7: 5,6                                  # 22 pairs
* PAIR C7: 1,4 ROW 7
H7: 1,4,5                                # reduction candidate for 1,4
H7: 1,4 => SOLVED
* 641258937527639184398471265465912378812743659973586421284397516156824793739165842
H7: 5                                    # 17 pairs
* PAIR A8: 1,4 COL A
A6: 1,4,9                                # reduction candidate for 1,4
A6: 9                                    # 21 pairs
A6: 1,4                                  # 18 pairs
* PAIR I7: 1,6 COL I
I5: 1,6,8,9                              # reduction candidate for 1,6
I5: 1,6 => CTR
* 6..258937527.3.184398.7.265..5.123.88.2943.....358642928.397....5682.793739.658.2
I5: 8,9                                  # 16 pairs
I6: 1,6,9                                # reduction candidate for 1,6
I6: 1,6                                  # 18 pairs
* PAIR H9: 1,4 BLK 9
H7: 1,4,5                                # reduction candidate for 1,4
H7: 1,4 => SOLVED
* 641258937527639184398471265465912378812743659973586421284397516156824793739165842
H7: 5                                    # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-289-base-pr-000.dot
* REASONING
* DIS # B6: 1,4 => CTR => B6: 6,7
* DIS # D5: 6,9 => CTR => D5: 5,7
* DIS # D6: 6,9 => CTR => D6: 5,7
* DIS # D5: 6,9 => CTR => D5: 5,7
* DIS # D6: 6,9 => CTR => D6: 5,7
* DIS # G6: 5,6 => CTR => G6: 4
* DIS # G7: 4 => CTR => G7: 5,6
* PRF # H7: 1,4 => SOL
* DIS # I5: 1,6 => CTR => I5: 8,9
* PRF # H7: 1,4 => SOL
* CNT  10 HDP CHAINS /  31 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B1,C1,C7,D2,D3,D9,F2,F3,F6,F8,G5,H4,H9,I7)
* 6..258937527.3.184398.7.265..5.123....2.43.....3.8..2.28.397....5682.793739.658.2
* PAIR B1: 1,4 COL B
B6: 1,4,6,7                              # reduction candidate for 1,4
B6: 1,4 => CTR
* 6.4258937527.3.184398174265..5.1234...254367..4378.52.28.397456456821793739465812
* PAIR RESTART
* PAIR D2: 6,9 COL D
D4: 6,9,7                                # reduction candidate for 6,9
D4: 6,9                                  # 21 pairs
D5: 6,9,5,7                              # reduction candidate for 6,9
D5: 6,9 => CTR
* 6..258937527.3.184398.7.265..571234...2.43.7.47358.6212843975...5682.793739.658.2
D6: 6,9,5,7                              # reduction candidate for 6,9
D6: 6,9 => CTR
* 6..258937527.3.184398.7.265..5.123....25436...73.8.52.28.397456456821793739465812
* RESTART
* PAIR RESTART
* PAIR F6: 6,9 ROW 6
I6: 6,9,1                                # reduction candidate for 6,9
I6: 6,9 => CTR
* 6..258937527.3.184398.7.265..5.123....2.43.1.1.3.8.42.281397....5682.793739.658.2
I6: 1 => SOLVED
* 641258937527639184398471265465912378812743659973586421284397516156824793739165842
* DURATION: 0:00:08.900672  START: 12:51:15.341815  END: 12:51:24.242487 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-289-base-pr-001.dot
* REASONING
* DIS # B6: 1,4 => CTR => B6: 6,7
* DIS B6: 6,7 # D5: 6,9 => CTR => D5: 5,7
* DIS B6: 6,7 + D5: 5,7 # D6: 6,9 => CTR => D6: 5,7
* DIS B6: 6,7 + D5: 5,7 + D6: 5,7 # I6: 6,9 => CTR => I6: 1
* PRF B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1 => SOL
* STA B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1
* CNT   5 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 289

solution: 641258937527639184398471265465912378812743659973586421284397516156824793739165842
info: 2370     FNBTWXY  S8.f     34957

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

Solution

position: 641258937527639184398471265465912378812743659973586421284397516156824793739165842 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 # B6: 1,4 => CTR => B6: 6,7
* INC # B6: 6,7 => UNS
* INC # D4: 6,9 => UNS
* DIS # D5: 6,9 => CTR => D5: 5,7
* INC # D5: 5,7 => UNS
* DIS # D6: 6,9 => CTR => D6: 5,7
* INC # D6: 5,7 => UNS
* INC # D4: 6,9 => UNS
* DIS # D5: 6,9 => CTR => D5: 5,7
* INC # D5: 5,7 => UNS
* DIS # D6: 6,9 => CTR => D6: 5,7
* INC # D6: 5,7 => UNS
* INC # I6: 6,9 => UNS
* INC # I6: 1 => UNS
* INC # B4: 4,7 => UNS
* INC # B4: 6 => UNS
* DIS # G6: 5,6 => CTR => G6: 4
* INC # G6: 4 => UNS
* INC # D5: 5,6 => UNS
* INC # D5: 7,9 => UNS
* INC # G7: 5,6 => UNS
* DIS # G7: 4 => CTR => G7: 5,6
* PRF # H7: 1,4 => SOL
* INC # H7: 5 => UNS
* INC # A6: 1,4 => UNS
* INC # A6: 9 => UNS
* DIS # I5: 1,6 => CTR => I5: 8,9
* INC # I5: 8,9 => UNS
* INC # I6: 1,6 => UNS
* PRF # H7: 1,4 => SOL
* INC # H7: 5 => UNS
* CNT  31 HDP CHAINS /  31 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B6: 1,4 => CTR => B6: 6,7
* INC B6: 6,7 # D4: 6,9 => UNS
* DIS B6: 6,7 # D5: 6,9 => CTR => D5: 5,7
* DIS B6: 6,7 + D5: 5,7 # D6: 6,9 => CTR => D6: 5,7
* DIS B6: 6,7 + D5: 5,7 + D6: 5,7 # I6: 6,9 => CTR => I6: 1
* PRF B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1 => SOL
* STA B6: 6,7 + D5: 5,7 + D6: 5,7 + I6: 1
* CNT   6 HDP CHAINS /   5 HYP OPENED