Analysis of xx-top500-177-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 3.9..45.....61..7..........5...39....7.....6...........6.2.....8.....3.....7..... initial

Autosolve

position: 3.98745.6...61.9736.739....5.6.397...73528.69.9..67.3576.2.3.9.8..9.63.793.7.16.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B3: 1,2 => SOL
* DIS # B3: 5 => CTR => B3: 1,2
* DIS # B2: 2,4 => CTR => B2: 5,8
* DIS # C2: 2,4 => CTR => C2: 5,8
* DIS # A6: 1 => CTR => A6: 2,4
* DIS # B2: 2,5 => CTR => B2: 4,8
* PRF # C2: 2,5 => SOL
* DIS # B3: 2,5 => CTR => B3: 1
* PRF # B3: 1 => SOL
* DIS # H3: 1,2 => CTR => H3: 4,8
* DIS # I3: 1,2 => CTR => I3: 4,8
* DIS # H4: 1,2 => CTR => H4: 4,8
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* PRF # G6: 1,4 => SOL
* PRF # G6: 1,4 => SOL
* DIS # G3: 1,4 => CTR => G3: 2,8
* DIS # C8: 4,5 => CTR => C8: 1,2
* DIS # H8: 4,5 => CTR => H8: 1,2
* CNT  21 HDP CHAINS /  44 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 # B3: 1,2 => SOL
* STA B3: 1,2
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

3.9..45.....61..7..........5...39....7.....6...........6.2.....8.....3.....7..... initial
3.98745.6...61.9736.739....5.6.397...73528.69.9..67.3576.2.3.9.8..9.63.793.7.16.. autosolve
329874516485612973617395248546139782173528469298467135764253891851946327932781654 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (10)
B1: 1,2
A2: 2,4
F2: 2,5
F3: 2,5
H1: 1,2
A5: 1,4
D4: 1,4
D6: 1,4
G5: 1,4
E8: 4,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B1,B3: 1.. / B1 = 1  =>  0 pairs (X) / B3 = 1  =>  0 pairs (_)
A5,A6: 1.. / A5 = 1  => 10 pairs (_) / A6 = 1  =>  0 pairs (X)
D4,D6: 1.. / D4 = 1  => 11 pairs (_) / D6 = 1  => 10 pairs (_)
C7,C8: 1.. / C7 = 1  =>  0 pairs (X) / C8 = 1  => 11 pairs (_)
B1,H1: 1.. / B1 = 1  =>  0 pairs (X) / H1 = 1  =>  0 pairs (_)
A5,G5: 1.. / A5 = 1  => 10 pairs (_) / G5 = 1  =>  0 pairs (X)
C8,H8: 1.. / C8 = 1  => 11 pairs (_) / H8 = 1  =>  0 pairs (X)
F2,F3: 2.. / F2 = 2  =>  0 pairs (*) / F3 = 2  =>  0 pairs (X)
B1,H1: 2.. / B1 = 2  =>  0 pairs (*) / H1 = 2  =>  0 pairs (X)
A2,A6: 2.. / A2 = 2  =>  0 pairs (X) / A6 = 2  =>  0 pairs (_)
G3,G6: 2.. / G3 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
D4,D6: 4.. / D4 = 4  => 10 pairs (_) / D6 = 4  => 11 pairs (_)
A5,G5: 4.. / A5 = 4  =>  0 pairs (X) / G5 = 4  => 10 pairs (_)
F2,F3: 5.. / F2 = 5  =>  0 pairs (X) / F3 = 5  =>  0 pairs (_)
H8,H9: 5.. / H8 = 5  =>  0 pairs (X) / H9 = 5  => 12 pairs (_)
B3,F3: 5.. / B3 = 5  =>  0 pairs (X) / F3 = 5  =>  0 pairs (_)
C7,E7: 5.. / C7 = 5  => 13 pairs (_) / E7 = 5  =>  0 pairs (*)
B2,C2: 8.. / B2 = 8  => 11 pairs (_) / C2 = 8  =>  0 pairs (X)
B4,C6: 8.. / B4 = 8  =>  0 pairs (X) / C6 = 8  => 11 pairs (_)
E7,E9: 8.. / E7 = 8  => 19 pairs (_) / E9 = 8  => 12 pairs (_)
C6,G6: 8.. / C6 = 8  => 11 pairs (_) / G6 = 8  =>  0 pairs (X)
B2,B4: 8.. / B2 = 8  => 11 pairs (_) / B4 = 8  =>  0 pairs (X)
C2,C6: 8.. / C2 = 8  =>  0 pairs (X) / C6 = 8  => 11 pairs (_)
* DURATION: 0:00:39.884824  START: 08:44:35.406768  END: 08:45:15.291592 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A5,B1,D4,D6,E8,F2,F3,G5,H1)
* 3.98745.6...61.9736.739....5.6.397...73528.69.9..67.3576.2.3.9.8..9.63.793.7.16..
* PAIR B1: 1,2 BLK 1
B3: 1,2,5                                # reduction candidate for 1,2
B3: 1,2 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
B3: 5 => CTR
* 3198745262..615973657392...526.397...73528.69.98.6723576.2.3.9.8429563179357.16.2
* PAIR A2: 2,4 BLK 1
B2: 2,4,5,8                              # reduction candidate for 2,4
B2: 2,4 => CTR
* 3.98745.6..8615973657392...586.397...73528.69.9..67.3576.2.3.9.8..9.63.793.7.16..
B2: 5,8                                  # 11 pairs
C2: 2,4,5,8                              # reduction candidate for 2,4
C2: 2,4 => CTR
* 319874526284615973657392...526.397...73528.69.98.6723576.2.3.9.8429563179357.16.2
C2: 5,8                                  # 11 pairs
* PAIR A2: 2,4 COL A
A6: 2,4,1                                # reduction candidate for 2,4
A6: 1 => CTR
* 3198745262..615973657392...5261397..47352816919846723576.2.3.9.8429563179357.16.2
A6: 2,4                                  # 10 pairs
* PAIR F2: 2,5 ROW 2
B2: 2,5,4,8                              # reduction candidate for 2,5
B2: 2,5 => CTR
* 3.98745.64.861.9736.739.284586.39742173528.69.9..6783576.2.3.9.84.9563.793.7.165.
B2: 4,8                                  # 11 pairs
C2: 2,5,4,8                              # reduction candidate for 2,5
C2: 2,5 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
C2: 4,8                                  # 12 pairs
* PAIR F3: 2,5 ROW 3
B3: 2,5,1                                # reduction candidate for 2,5
B3: 2,5 => CTR
* 3198745262..615973657392...526.397...73528.69.98.6723576.2.3.9.8429563179357.16.2
B3: 1 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
* PAIR H1: 1,2 BLK 3
G3: 1,2,4,8                              # reduction candidate for 1,2
G3: 1,2                                  # 13 pairs
H3: 1,2,4,8                              # reduction candidate for 1,2
H3: 1,2 => CTR
* 3.98745.62..615973657392.1.526.397...73528.69.98.6723576.2.3.9.8419563.793.7.16.2
H3: 4,8                                  # 11 pairs
I3: 1,2,4,8                              # reduction candidate for 1,2
I3: 1,2 => CTR
* 3.98745.62..615973657392..1526.397...73528.69.98.6723576.2.3.9.84.9563.793.7.1652
I3: 4,8                                  # 11 pairs
* PAIR H1: 1,2 COL H
H4: 1,2,4,8                              # reduction candidate for 1,2
H4: 1,2 => CTR
* 319874526...61.9736.739....5.6.397...73528.69.9..67.3576.2.3.9.8219.63.793.7.16.2
H4: 4,8                                  # 11 pairs
H8: 1,2,4,5                              # reduction candidate for 1,2
H8: 1,2                                  # 15 pairs
* PAIR A5: 1,4 BLK 4
A6: 1,4,2                                # reduction candidate for 1,4
A6: 1,4 => CTR
* 3198745262..615973657392...526.397...73528.69.98.6723576.2.3.9.8429563179357.16.2
A6: 2 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
* PAIR D4: 1,4 ROW 4
H4: 1,4,2,8                              # reduction candidate for 1,4
H4: 1,4                                  # 14 pairs
I4: 1,4,2,8                              # reduction candidate for 1,4
I4: 1,4                                  # 14 pairs
* PAIR D6: 1,4 ROW 6
A6: 1,4,2                                # reduction candidate for 1,4
A6: 1,4 => CTR
* 3198745262..615973657392...526.397...73528.69.98.6723576.2.3.9.8429563179357.16.2
A6: 2 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
G6: 1,4,2,8                              # reduction candidate for 1,4
G6: 1,4 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
G6: 2,8                                  # 11 pairs
* PAIR G5: 1,4 BLK 6
H4: 1,4,2,8                              # reduction candidate for 1,4
H4: 1,4                                  # 14 pairs
I4: 1,4,2,8                              # reduction candidate for 1,4
I4: 1,4                                  # 14 pairs
G6: 1,4,2,8                              # reduction candidate for 1,4
G6: 1,4 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
G6: 2,8                                  # 11 pairs
* PAIR G5: 1,4 COL G
G3: 1,4,2,8                              # reduction candidate for 1,4
G3: 1,4 => CTR
* 3.98745.62..615973657392...526.397...73528.69.98.6723576.2.389.84.9563.793.78165.
G3: 2,8                                  # 11 pairs
G7: 1,4,8                                # reduction candidate for 1,4
G7: 1,4                                  # 13 pairs
* PAIR E8: 4,5 BLK 8
E7: 4,5,8                                # reduction candidate for 4,5
E7: 4,5                                  # 12 pairs
E9: 4,5,8                                # reduction candidate for 4,5
E9: 4,5                                  # 19 pairs
* PAIR E8: 4,5 ROW 8
B8: 4,5,2                                # reduction candidate for 4,5
B8: 4,5                                  # 18 pairs
C8: 4,5,1,2                              # reduction candidate for 4,5
C8: 4,5 => CTR
* 319874526...61.9736.739....526.397...73528.69.98.67235761253.9.85.946317934781652
C8: 1,2                                  # 11 pairs
H8: 4,5,1,2                              # reduction candidate for 4,5
H8: 4,5 => CTR
* 319874526...61.973657392...5.6.397.2.73528.69.9..67.3576.2.3.9.8219.63.793.7.16..
H8: 1,2                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-177-base-pr-000.dot
* REASONING
* PRF # B3: 1,2 => SOL
* DIS # B3: 5 => CTR => B3: 1,2
* DIS # B2: 2,4 => CTR => B2: 5,8
* DIS # C2: 2,4 => CTR => C2: 5,8
* DIS # A6: 1 => CTR => A6: 2,4
* DIS # B2: 2,5 => CTR => B2: 4,8
* PRF # C2: 2,5 => SOL
* DIS # B3: 2,5 => CTR => B3: 1
* PRF # B3: 1 => SOL
* DIS # H3: 1,2 => CTR => H3: 4,8
* DIS # I3: 1,2 => CTR => I3: 4,8
* DIS # H4: 1,2 => CTR => H4: 4,8
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* PRF # G6: 1,4 => SOL
* PRF # G6: 1,4 => SOL
* DIS # G3: 1,4 => CTR => G3: 2,8
* DIS # C8: 4,5 => CTR => C8: 1,2
* DIS # H8: 4,5 => CTR => H8: 1,2
* CNT  21 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A5,B1,D4,D6,E8,F2,F3,G5,H1)
* 3.98745.6...61.9736.739....5.6.397...73528.69.9..67.3576.2.3.9.8..9.63.793.7.16..
* PAIR B1: 1,2 BLK 1
B3: 1,2,5                                # reduction candidate for 1,2
B3: 1,2 => SOLVED
* 329874516485612973617395248546139782173528469298467135764253891851946327932781654
* DURATION: 0:00:02.129791  START: 08:45:55.768623  END: 08:45:57.898414 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-177-base-pr-001.dot
* REASONING
* PRF # B3: 1,2 => SOL
* STA B3: 1,2
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 177

solution: 329874516485612973617395248546139782173528469298467135764253891851946327932781654
info: 1827     FNBTWY   S8.f     29889

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

Solution

position: 329874516485612973617395248546139782173528469298467135764253891851946327932781654 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 # B3: 1,2 => SOL
* DIS # B3: 5 => CTR => B3: 1,2
* DIS # B2: 2,4 => CTR => B2: 5,8
* INC # B2: 5,8 => UNS
* DIS # C2: 2,4 => CTR => C2: 5,8
* INC # C2: 5,8 => UNS
* INC # A6: 2,4 => UNS
* DIS # A6: 1 => CTR => A6: 2,4
* DIS # B2: 2,5 => CTR => B2: 4,8
* INC # B2: 4,8 => UNS
* PRF # C2: 2,5 => SOL
* INC # C2: 4,8 => UNS
* DIS # B3: 2,5 => CTR => B3: 1
* PRF # B3: 1 => SOL
* INC # G3: 1,2 => UNS
* DIS # H3: 1,2 => CTR => H3: 4,8
* INC # H3: 4,8 => UNS
* DIS # I3: 1,2 => CTR => I3: 4,8
* INC # I3: 4,8 => UNS
* DIS # H4: 1,2 => CTR => H4: 4,8
* INC # H4: 4,8 => UNS
* INC # H8: 1,2 => UNS
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* INC # H4: 1,4 => UNS
* INC # I4: 1,4 => UNS
* DIS # A6: 1,4 => CTR => A6: 2
* PRF # A6: 2 => SOL
* PRF # G6: 1,4 => SOL
* INC # G6: 2,8 => UNS
* INC # H4: 1,4 => UNS
* INC # I4: 1,4 => UNS
* PRF # G6: 1,4 => SOL
* INC # G6: 2,8 => UNS
* DIS # G3: 1,4 => CTR => G3: 2,8
* INC # G3: 2,8 => UNS
* INC # G7: 1,4 => UNS
* INC # E7: 4,5 => UNS
* INC # E9: 4,5 => UNS
* INC # B8: 4,5 => UNS
* DIS # C8: 4,5 => CTR => C8: 1,2
* INC # C8: 1,2 => UNS
* DIS # H8: 4,5 => CTR => H8: 1,2
* INC # H8: 1,2 => UNS
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # B3: 1,2 => SOL
* STA B3: 1,2
* CNT   1 HDP CHAINS /   1 HYP OPENED