Analysis of xx-top500-281-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 1...2.7...635.................4...352...1...........6.7.....1...5.6......8....... initial

Autosolve

position: 1...2.7...635...............1.4...352...1...........617.....1...5.6..3...8....... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # C1: 4,9 => SOL
* DIS # A3: 4,9 => CTR => A3: 5,8
* DIS # F1: 4,9 => CTR => F1: 3,6,8
* DIS # H1: 4,9 => CTR => H1: 5,8
* DIS # I1: 4,9 => CTR => I1: 3,6,8
* DIS # B6: 4,9 => CTR => B6: 3,7
* DIS # B7: 4,9 => CTR => B7: 2,3
* DIS # B7: 4,9 => CTR => B7: 2,3
* PRF # C7: 4,9 => SOL
* DIS # A9: 4,9 => CTR => A9: 3,6
* DIS # A3: 4,9 => CTR => A3: 5,8
* DIS # A6: 4,9 => CTR => A6: 3,5,8
* CNT  12 HDP CHAINS /  33 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 # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

1...2.7...635.................4...352...1...........6.7.....1...5.6......8....... initial
1...2.7...635...............1.4...352...1...........617.....1...5.6..3...8....... autosolve
194826753863574912527139684918467235246315897375982461739258146452691378681743529 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
B1: 4,9
B3: 2,7
C3: 2,7
G3: 5,6
C5: 5,6
F5: 5,6
A8: 4,9
G9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H2,H3: 1.. / H2 = 1  =>  8 pairs (_) / H3 = 1  =>  0 pairs (X)
C8,C9: 1.. / C8 = 1  =>  8 pairs (_) / C9 = 1  =>  8 pairs (_)
F2,H2: 1.. / F2 = 1  =>  0 pairs (X) / H2 = 1  =>  8 pairs (_)
C8,F8: 1.. / C8 = 1  =>  8 pairs (_) / F8 = 1  =>  8 pairs (_)
D3,D9: 1.. / D3 = 1  =>  8 pairs (_) / D9 = 1  =>  0 pairs (X)
B3,C3: 2.. / B3 = 2  =>  6 pairs (_) / C3 = 2  =>  0 pairs (X)
H2,I2: 2.. / H2 = 2  =>  0 pairs (X) / I2 = 2  =>  8 pairs (_)
G4,G6: 2.. / G4 = 2  =>  8 pairs (_) / G6 = 2  => 10 pairs (_)
F4,G4: 2.. / F4 = 2  => 10 pairs (_) / G4 = 2  =>  8 pairs (_)
B3,B7: 2.. / B3 = 2  =>  6 pairs (_) / B7 = 2  =>  0 pairs (X)
I1,I3: 3.. / I1 = 3  =>  0 pairs (*) / I3 = 3  =>  0 pairs (X)
B7,A9: 3.. / B7 = 3  =>  0 pairs (*) / A9 = 3  =>  0 pairs (X)
B5,D5: 3.. / B5 = 3  =>  0 pairs (X) / D5 = 3  => 15 pairs (_)
A6,A9: 3.. / A6 = 3  =>  0 pairs (*) / A9 = 3  =>  0 pairs (X)
C1,A3: 5.. / C1 = 5  =>  0 pairs (X) / A3 = 5  =>  0 pairs (_)
C1,H1: 5.. / C1 = 5  =>  0 pairs (X) / H1 = 5  =>  0 pairs (_)
C5,F5: 5.. / C5 = 5  =>  0 pairs (X) / F5 = 5  =>  0 pairs (_)
A3,A6: 5.. / A3 = 5  =>  0 pairs (*) / A6 = 5  =>  0 pairs (X)
G3,G9: 5.. / G3 = 5  =>  0 pairs (X) / G9 = 5  =>  0 pairs (_)
F1,I1: 6.. / F1 = 6  =>  0 pairs (*) / I1 = 6  =>  0 pairs (X)
C5,F5: 6.. / C5 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
C7,I7: 6.. / C7 = 6  =>  0 pairs (X) / I7 = 6  =>  0 pairs (_)
A4,A9: 6.. / A4 = 6  =>  0 pairs (X) / A9 = 6  =>  0 pairs (_)
E3,E4: 6.. / E3 = 6  =>  0 pairs (X) / E4 = 6  =>  0 pairs (_)
G3,G9: 6.. / G3 = 6  =>  0 pairs (*) / G9 = 6  =>  0 pairs (X)
B3,C3: 7.. / B3 = 7  =>  0 pairs (X) / C3 = 7  =>  6 pairs (_)
E2,F2: 7.. / E2 = 7  =>  8 pairs (_) / F2 = 7  =>  8 pairs (_)
H5,I5: 7.. / H5 = 7  =>  8 pairs (_) / I5 = 7  =>  8 pairs (_)
B3,B6: 7.. / B3 = 7  =>  0 pairs (X) / B6 = 7  =>  6 pairs (_)
D6,D9: 7.. / D6 = 7  =>  0 pairs (X) / D9 = 7  =>  8 pairs (_)
* DURATION: 0:00:48.777995  START: 12:32:35.483396  END: 12:33:24.261391 2017-05-04
* CP COUNT: (30)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B1,B3,C3,C5,F5,G3,G9)
* 1...2.7...635...............1.4...352...1...........617.....1...5.6..3...8.......
* PAIR B1: 4,9 BLK 1
C1: 4,9,5,8                              # reduction candidate for 4,9
C1: 4,9 => SOLVED
* 194826753863574912527139684918467235246315897375982461739258146452691378681743529
C1: 5,8                                  #  9 pairs
A2: 4,9,8                                # reduction candidate for 4,9
A2: 4,9                                  # 13 pairs
A3: 4,9,5,8                              # reduction candidate for 4,9
A3: 4,9 => CTR
* 1.5.2.7..8635...............1.4...352.6.15...5......617.....1.6.5.6..3...8.......
A3: 5,8                                  #  9 pairs
* PAIR B1: 4,9 ROW 1
F1: 4,9,3,6,8                            # reduction candidate for 4,9
F1: 4,9 => CTR
* 1...2.7.6.635...........5.3.1.4...352...1....5......617.6...1...5.6..3...8.......
F1: 3,6,8                                #  8 pairs
H1: 4,9,5,8                              # reduction candidate for 4,9
H1: 4,9 => CTR
* 1.5.2.7...635...............1.4...352.6.15...5......617.....1.6.5.6..3...8.......
H1: 5,8                                  #  9 pairs
I1: 4,9,3,6,8                            # reduction candidate for 4,9
I1: 4,9 => CTR
* 1..3267...635...........6.3.1.46..35236.15..........617...531.6.5.6..3..68....5..
I1: 3,6,8                                #  8 pairs
* PAIR B1: 4,9 COL B
B5: 4,9,3                                # reduction candidate for 4,9
B5: 4,9                                  # 15 pairs
B6: 4,9,3,7                              # reduction candidate for 4,9
B6: 4,9 => CTR
* 1...2.756.635......72......61.4...35235.16..........6172....1...5.6..3..38.......
B6: 3,7                                  #  9 pairs
B7: 4,9,2,3                              # reduction candidate for 4,9
B7: 4,9 => CTR
* 1...2.756.635......271.....61.4...35235.16....7.....617.....1...5.6..3..38.7.....
B7: 2,3                                  #  9 pairs
* PAIR A8: 4,9 BLK 7
B7: 4,9,2,3                              # reduction candidate for 4,9
B7: 4,9 => CTR
* 1...2.756.635......271.....61.4...35235.16....7.....617.....1...5.6..3..38.7.....
B7: 2,3                                  #  9 pairs
C7: 4,9,2,6                              # reduction candidate for 4,9
C7: 4,9 => SOLVED
* 194826753863574912527139684918467235246315897375982461739258146452691378681743529
C7: 2,6                                  #  9 pairs
C8: 4,9,1,2                              # reduction candidate for 4,9
C8: 4,9                                  # 16 pairs
A9: 4,9,3,6                              # reduction candidate for 4,9
A9: 4,9 => CTR
* 1...2.756.635..............61.4...352.5.16...3......6173....1...5.6..3...8.......
A9: 3,6                                  #  9 pairs
C9: 4,9,1,2,6                            # reduction candidate for 4,9
C9: 4,9                                  # 14 pairs
* PAIR A8: 4,9 ROW 8
E8: 4,9,7,8                              # reduction candidate for 4,9
E8: 4,9                                  # 10 pairs
F8: 4,9,1,2,7,8                          # reduction candidate for 4,9
F8: 4,9                                  # 10 pairs
H8: 4,9,2,7,8                            # reduction candidate for 4,9
H8: 4,9                                  # 11 pairs
I8: 4,9,2,7,8                            # reduction candidate for 4,9
I8: 4,9                                  # 11 pairs
* PAIR A8: 4,9 COL A
A2: 4,9,8                                # reduction candidate for 4,9
A2: 4,9                                  # 13 pairs
A3: 4,9,5,8                              # reduction candidate for 4,9
A3: 4,9 => CTR
* 1.5.2.7..8635...............1.4...352.6.15...5......617.....1.6.5.6..3...8.......
A3: 5,8                                  #  9 pairs
A6: 4,9,3,5,8                            # reduction candidate for 4,9
A6: 4,9 => CTR
* 1...2.7...635.....5.....6...1.46..352.6.15.....5....617.....1.6.5.6..3...8.......
A6: 3,5,8                                #  8 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-281-base-pr-000.dot
* REASONING
* PRF # C1: 4,9 => SOL
* DIS # A3: 4,9 => CTR => A3: 5,8
* DIS # F1: 4,9 => CTR => F1: 3,6,8
* DIS # H1: 4,9 => CTR => H1: 5,8
* DIS # I1: 4,9 => CTR => I1: 3,6,8
* DIS # B6: 4,9 => CTR => B6: 3,7
* DIS # B7: 4,9 => CTR => B7: 2,3
* DIS # B7: 4,9 => CTR => B7: 2,3
* PRF # C7: 4,9 => SOL
* DIS # A9: 4,9 => CTR => A9: 3,6
* DIS # A3: 4,9 => CTR => A3: 5,8
* DIS # A6: 4,9 => CTR => A6: 3,5,8
* CNT  12 HDP CHAINS /  33 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B1,B3,C3,C5,F5,G3,G9)
* 1...2.7...635...............1.4...352...1...........617.....1...5.6..3...8.......
* PAIR B1: 4,9 BLK 1
C1: 4,9,5,8                              # reduction candidate for 4,9
C1: 4,9 => SOLVED
* 194826753863574912527139684918467235246315897375982461739258146452691378681743529
* DURATION: 0:00:02.756341  START: 12:33:50.690353  END: 12:33:53.446694 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-281-base-pr-001.dot
* REASONING
* PRF # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 281

solution: 194826753863574912527139684918467235246315897375982461739258146452691378681743529
info: 2266     FNBHWXY  S8.f     25224

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

Solution

position: 194826753863574912527139684918467235246315897375982461739258146452691378681743529 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 # C1: 4,9 => SOL
* INC # C1: 5,8 => UNS
* INC # A2: 4,9 => UNS
* DIS # A3: 4,9 => CTR => A3: 5,8
* INC # A3: 5,8 => UNS
* DIS # F1: 4,9 => CTR => F1: 3,6,8
* INC # F1: 3,6,8 => UNS
* DIS # H1: 4,9 => CTR => H1: 5,8
* INC # H1: 5,8 => UNS
* DIS # I1: 4,9 => CTR => I1: 3,6,8
* INC # I1: 3,6,8 => UNS
* INC # B5: 4,9 => UNS
* DIS # B6: 4,9 => CTR => B6: 3,7
* INC # B6: 3,7 => UNS
* DIS # B7: 4,9 => CTR => B7: 2,3
* INC # B7: 2,3 => UNS
* DIS # B7: 4,9 => CTR => B7: 2,3
* INC # B7: 2,3 => UNS
* PRF # C7: 4,9 => SOL
* INC # C7: 2,6 => UNS
* INC # C8: 4,9 => UNS
* DIS # A9: 4,9 => CTR => A9: 3,6
* INC # A9: 3,6 => UNS
* INC # C9: 4,9 => UNS
* INC # E8: 4,9 => UNS
* INC # F8: 4,9 => UNS
* INC # H8: 4,9 => UNS
* INC # I8: 4,9 => UNS
* INC # A2: 4,9 => UNS
* DIS # A3: 4,9 => CTR => A3: 5,8
* INC # A3: 5,8 => UNS
* DIS # A6: 4,9 => CTR => A6: 3,5,8
* INC # A6: 3,5,8 => UNS
* CNT  33 HDP CHAINS /  33 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # C1: 4,9 => SOL
* STA C1: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED