Analysis of xx-top500-500-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2..7.5...9.3...........1..4...5...........36.......9..6.9.2...1..4.....5........ initial

Autosolve

position: 321.745.9.95321......59.1234...59...95.....3621.....95.6.9.2.5.1..4.5...5........ autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A3: 7 => CTR => A3: 6,8
* DIS # H2: 6,8 => CTR => H2: 4,7
* DIS # D4: 6,8 => CTR => D4: 2,7
* PRF # D4: 2,7 => SOL
* PRF # D6: 6,8 => SOL
* DIS # D6: 7 => CTR => D6: 6,8
* DIS # D9: 6,8 => CTR => D9: 1,7
* DIS # A3: 7 => CTR => A3: 6,8
* PRF # F6: 6,8 => SOL
* DIS # F9: 6,8 => CTR => F9: 3,7
* DIS # H2: 6,8 => CTR => H2: 4,7
* DIS # B4: 7,8 => CTR => B4: 3
* PRF # B4: 3 => SOL
* DIS # C4: 7,8 => CTR => C4: 3,6
* PRF # C6: 7,8 => SOL
* DIS # C6: 6 => CTR => C6: 7,8
* DIS # C3: 7,8 => CTR => C3: 4
* PRF # C3: 4 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* DIS # D4: 7,8 => CTR => D4: 2,6
* DIS # F6: 7,8 => CTR => F6: 3,6
* DIS # F9: 7,8 => CTR => F9: 3,6
* PRF # F9: 3,6 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* PRF # G7: 7,8 => SOL
* DIS # G7: 3 => CTR => G7: 7,8
* DIS # I7: 7,8 => CTR => I7: 1,4
* DIS # A3: 7,8 => CTR => A3: 6
* PRF # A3: 6 => SOL
* CNT  29 HDP CHAINS /  52 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 # A3: 7 => CTR => A3: 6,8
* DIS A3: 6,8 # H2: 6,8 => CTR => H2: 4,7
* DIS A3: 6,8 + H2: 4,7 # G2: 7 => CTR => G2: 6,8
* DIS A3: 6,8 + H2: 4,7 + G2: 6,8 # D4: 6,8 => CTR => D4: 2,7
* PRF A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7 => SOL
* STA A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7
* CNT   5 HDP CHAINS /   7 HYP OPENED

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

Details

Positions

.2..7.5...9.3...........1..4...5...........36.......9..6.9.2...1..4.....5........ initial
321.745.9.95321......59.1234...59...95.....3621.....95.6.9.2.5.1..4.5...5........ autosolve
321674589895321647674598123436259718958147236217836495763912854189465372542783961 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (12)
A2: 6,8
D1: 6,8
F3: 6,8
H1: 6,8
C5: 7,8
D5: 1,2
E5: 1,4
F5: 7,8
G5: 2,4
A7: 7,8
C8: 2,9
C9: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D5,E5: 1.. / D5 = 1  =>  0 pairs (*) / E5 = 1  =>  0 pairs (X)
H4,I4: 1.. / H4 = 1  => 12 pairs (_) / I4 = 1  =>  0 pairs (X)
E7,I7: 1.. / E7 = 1  =>  0 pairs (*) / I7 = 1  =>  0 pairs (X)
D5,D9: 1.. / D5 = 1  =>  0 pairs (*) / D9 = 1  =>  0 pairs (X)
H4,H9: 1.. / H4 = 1  => 12 pairs (_) / H9 = 1  =>  0 pairs (X)
D4,D5: 2.. / D4 = 2  =>  0 pairs (*) / D5 = 2  =>  0 pairs (X)
C8,C9: 2.. / C8 = 2  => 11 pairs (_) / C9 = 2  => 10 pairs (_)
D5,G5: 2.. / D5 = 2  =>  0 pairs (X) / G5 = 2  =>  0 pairs (_)
B4,C4: 3.. / B4 = 3  =>  0 pairs (*) / C4 = 3  =>  0 pairs (X)
E6,F6: 3.. / E6 = 3  =>  0 pairs (*) / F6 = 3  =>  0 pairs (X)
C4,C7: 3.. / C4 = 3  =>  0 pairs (X) / C7 = 3  =>  0 pairs (_)
F6,F9: 3.. / F6 = 3  => 12 pairs (_) / F9 = 3  =>  0 pairs (*)
B3,C3: 4.. / B3 = 4  =>  0 pairs (X) / C3 = 4  =>  0 pairs (_)
H2,I2: 4.. / H2 = 4  => 13 pairs (_) / I2 = 4  =>  0 pairs (X)
E5,E6: 4.. / E5 = 4  =>  0 pairs (*) / E6 = 4  =>  0 pairs (X)
G5,G6: 4.. / G5 = 4  =>  0 pairs (X) / G6 = 4  =>  0 pairs (_)
C7,B9: 4.. / C7 = 4  =>  0 pairs (X) / B9 = 4  =>  0 pairs (_)
E5,G5: 4.. / E5 = 4  =>  0 pairs (*) / G5 = 4  =>  0 pairs (X)
E6,G6: 4.. / E6 = 4  =>  0 pairs (X) / G6 = 4  =>  0 pairs (_)
C7,I7: 4.. / C7 = 4  =>  0 pairs (X) / I7 = 4  =>  0 pairs (_)
B3,B9: 4.. / B3 = 4  =>  0 pairs (X) / B9 = 4  =>  0 pairs (_)
C3,C7: 4.. / C3 = 4  =>  0 pairs (*) / C7 = 4  =>  0 pairs (X)
H2,H9: 4.. / H2 = 4  => 13 pairs (_) / H9 = 4  =>  0 pairs (X)
A2,A3: 6.. / A2 = 6  =>  0 pairs (X) / A3 = 6  =>  0 pairs (_)
D1,F3: 6.. / D1 = 6  =>  0 pairs (*) / F3 = 6  =>  0 pairs (X)
C4,C6: 6.. / C4 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
D1,H1: 6.. / D1 = 6  =>  0 pairs (*) / H1 = 6  =>  0 pairs (X)
A3,F3: 6.. / A3 = 6  =>  0 pairs (*) / F3 = 6  =>  0 pairs (X)
C4,D4: 6.. / C4 = 6  =>  0 pairs (*) / D4 = 6  =>  0 pairs (X)
D9,F9: 7.. / D9 = 7  =>  0 pairs (*) / F9 = 7  =>  0 pairs (X)
C5,F5: 7.. / C5 = 7  =>  0 pairs (X) / F5 = 7  =>  0 pairs (_)
A3,A7: 7.. / A3 = 7  =>  0 pairs (X) / A7 = 7  => 16 pairs (_)
D1,F3: 8.. / D1 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
D1,H1: 8.. / D1 = 8  =>  0 pairs (X) / H1 = 8  =>  0 pairs (_)
C5,F5: 8.. / C5 = 8  =>  0 pairs (*) / F5 = 8  =>  0 pairs (X)
C8,C9: 9.. / C8 = 9  => 10 pairs (_) / C9 = 9  => 11 pairs (_)
G8,G9: 9.. / G8 = 9  => 11 pairs (_) / G9 = 9  => 10 pairs (_)
C8,G8: 9.. / C8 = 9  => 10 pairs (_) / G8 = 9  => 11 pairs (_)
C9,G9: 9.. / C9 = 9  => 11 pairs (_) / G9 = 9  => 10 pairs (_)
* DURATION: 0:01:17.700129  START: 19:47:17.179046  END: 19:48:34.879175 2017-05-04
* CP COUNT: (39)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A7,C5,C8,C9,D1,D5,E5,F3,F5,G5,H1)
* 321.745.9.95321......59.1234...59...95.....3621.....95.6.9.2.5.1..4.5...5........
* PAIR A2: 6,8 BLK 1
A3: 6,8,7                                # reduction candidate for 6,8
A3: 7 => CTR
* 321874569695321...7..5961234.3659...95.21.43621674389586.932.5.1..4.5...5........
A3: 6,8                                  # 16 pairs
* PAIR A2: 6,8 ROW 2
G2: 6,8,7                                # reduction candidate for 6,8
G2: 6,8                                  # 15 pairs
H2: 6,8,4,7                              # reduction candidate for 6,8
H2: 6,8 => CTR
* 321.745.9.953217.4.4.59.1234.3659.1795.21.436216.438957649.23511..4.5.7.5..1.7.4.
H2: 4,7                                  # 13 pairs
* PAIR D1: 6,8 COL D
D4: 6,8,2,7                              # reduction candidate for 6,8
D4: 6,8 => CTR
* 3218745696953217...48596123483659217957218436216743895.649.2.511..4.5...5..1.7...
D4: 2,7 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
D6: 6,8,7                                # reduction candidate for 6,8
D6: 6,8 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
D6: 7 => CTR
* 3218745696953217..8745961234.3659...957218436216743895.6.9823511..4.5...5..1.7...
D9: 6,8,1,7                              # reduction candidate for 6,8
D9: 6,8 => CTR
* 321874569695321.....4596123436259...957148236218763495.639.2.541..4.56..54...7...
D9: 1,7                                  # 13 pairs
* PAIR F3: 6,8 ROW 3
A3: 6,8,7                                # reduction candidate for 6,8
A3: 7 => CTR
* 321874569695321...7..5961234.3659...95.21.43621674389586.932.5.1..4.5...5........
A3: 6,8                                  # 16 pairs
* PAIR F3: 6,8 COL F
F6: 6,8,3,7                              # reduction candidate for 6,8
F6: 6,8 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
F6: 3,7                                  # 13 pairs
F9: 6,8,3,7                              # reduction candidate for 6,8
F9: 6,8 => CTR
* 321.745.9.95321647674598123436259...9581472362178634957639128541..4.5...54.7.....
F9: 3,7                                  # 13 pairs
* PAIR H1: 6,8 BLK 3
G2: 6,8,7                                # reduction candidate for 6,8
G2: 6,8                                  # 15 pairs
H2: 6,8,4,7                              # reduction candidate for 6,8
H2: 6,8 => CTR
* 321.745.9.953217.4.4.59.1234.3659.1795.21.436216.438957649.23511..4.5.7.5..1.7.4.
H2: 4,7                                  # 13 pairs
* PAIR H1: 6,8 COL H
H8: 6,8,7                                # reduction candidate for 6,8
H8: 6,8                                  # 16 pairs
H9: 6,8,1,4                              # reduction candidate for 6,8
H9: 6,8                                  # 20 pairs
* PAIR C5: 7,8 BLK 4
B4: 7,8,3                                # reduction candidate for 7,8
B4: 7,8 => CTR
* 3218745696953217...48596123483659217957218436216743895.649.2.511..4.5...5..1.7...
B4: 3 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
C4: 7,8,3,6                              # reduction candidate for 7,8
C4: 7,8 => CTR
* 321.745.9.95321......59.12343.659...95.21.436216.43.95.63982.5.1..4.5...5........
C4: 3,6                                  # 13 pairs
C6: 7,8,6                                # reduction candidate for 7,8
C6: 7,8 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
C6: 6 => CTR
* 3218745696953217...48596123483659217957218436216743895.649.2.511..4.5...5..1.7...
* PAIR C5: 7,8 COL C
C3: 7,8,4                                # reduction candidate for 7,8
C3: 7,8 => CTR
* 321874569695321....4.5961234.3659.1.957218436216743895.649.2.5117.4.5.82532187...
C3: 4 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
C7: 7,8,3,4                              # reduction candidate for 7,8
C7: 7,8 => CTR
* 321.745.9.95321.....459.1234.3659...95.21.436216.43.95.6.9.2.5.1..4.5...5........
C7: 3,4                                  # 13 pairs
* PAIR F5: 7,8 BLK 5
D4: 7,8,2,6                              # reduction candidate for 7,8
D4: 7,8 => CTR
* 321.745.9.95321......59.1234.6.59...95.21.43621..43.95.63982.5.1..4.5...5........
D4: 2,6                                  # 13 pairs
D6: 7,8,6                                # reduction candidate for 7,8
D6: 7,8                                  # 15 pairs
F6: 7,8,3,6                              # reduction candidate for 7,8
F6: 7,8 => CTR
* 321874569695321......5961234.6259...95.14.23621.63.495.639.2.541..4.53..54.7.3...
F6: 3,6                                  # 13 pairs
* PAIR F5: 7,8 COL F
F9: 7,8,3,6                              # reduction candidate for 7,8
F9: 7,8 => CTR
* 3218745696953217..8..596123483659...95.21.436216743895.6.9823511..4.5...5..1.7...
F9: 3,6 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
* PAIR A7: 7,8 BLK 7
C7: 7,8,3,4                              # reduction candidate for 7,8
C7: 7,8 => CTR
* 321.745.9.95321.....459.1234.3659...95.21.436216.43.95.6.9.2.5.1..4.5...5........
C7: 3,4                                  # 13 pairs
B8: 7,8,3                                # reduction candidate for 7,8
B8: 7,8                                  # 15 pairs
* PAIR A7: 7,8 ROW 7
G7: 7,8,3                                # reduction candidate for 7,8
G7: 7,8 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
G7: 3 => CTR
* 321874569695321...8..5961234.3659.1.95.21.436216.43.95.6.9823511..4.5...5..1.7...
I7: 7,8,1,4                              # reduction candidate for 7,8
I7: 7,8 => CTR
* 321.745.9.95321....4.59.1234.3659...95.....3621.....95.6491235.1..4.5...5........
I7: 1,4                                  # 13 pairs
* PAIR A7: 7,8 COL A
A3: 7,8,6                                # reduction candidate for 7,8
A3: 7,8 => CTR
* 3218745696953217..8..596123483659...95.21.436216743895.6.9823511..4.5...5..1.7...
A3: 6 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
* PAIR C8: 2,9 ROW 8
G8: 2,9,3,6,7,8                          # reduction candidate for 2,9
G8: 2,9                                  # 14 pairs
G8: 3,6,7,8                              # 10 pairs
* PAIR C9: 2,9 ROW 9
G9: 2,9,3,6,8                            # reduction candidate for 2,9
G9: 3,6,8                                # 13 pairs
G9: 2,9                                  # 13 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-500-base-pr-000.dot
* REASONING
* DIS # A3: 7 => CTR => A3: 6,8
* DIS # H2: 6,8 => CTR => H2: 4,7
* DIS # D4: 6,8 => CTR => D4: 2,7
* PRF # D4: 2,7 => SOL
* PRF # D6: 6,8 => SOL
* DIS # D6: 7 => CTR => D6: 6,8
* DIS # D9: 6,8 => CTR => D9: 1,7
* DIS # A3: 7 => CTR => A3: 6,8
* PRF # F6: 6,8 => SOL
* DIS # F9: 6,8 => CTR => F9: 3,7
* DIS # H2: 6,8 => CTR => H2: 4,7
* DIS # B4: 7,8 => CTR => B4: 3
* PRF # B4: 3 => SOL
* DIS # C4: 7,8 => CTR => C4: 3,6
* PRF # C6: 7,8 => SOL
* DIS # C6: 6 => CTR => C6: 7,8
* DIS # C3: 7,8 => CTR => C3: 4
* PRF # C3: 4 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* DIS # D4: 7,8 => CTR => D4: 2,6
* DIS # F6: 7,8 => CTR => F6: 3,6
* DIS # F9: 7,8 => CTR => F9: 3,6
* PRF # F9: 3,6 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* PRF # G7: 7,8 => SOL
* DIS # G7: 3 => CTR => G7: 7,8
* DIS # I7: 7,8 => CTR => I7: 1,4
* DIS # A3: 7,8 => CTR => A3: 6
* PRF # A3: 6 => SOL
* CNT  29 HDP CHAINS /  52 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A7,C5,C8,C9,D1,D5,E5,F3,F5,G5,H1)
* 321.745.9.95321......59.1234...59...95.....3621.....95.6.9.2.5.1..4.5...5........
* PAIR A2: 6,8 BLK 1
A3: 6,8,7                                # reduction candidate for 6,8
A3: 7 => CTR
* 321874569695321...7..5961234.3659...95.21.43621674389586.932.5.1..4.5...5........
* PAIR A2: 6,8 ROW 2
G2: 6,8,7                                # reduction candidate for 6,8
G2: 6,8                                  # 19 pairs
H2: 6,8,4,7                              # reduction candidate for 6,8
H2: 6,8 => CTR
* 321.745.9.953217.4.4759.123473659.1.9582174362168...957649.2.5.1..4.5...5......4.
* RESTART
* PAIR A2: 6,8 ROW 2
G2: 6,8,7                                # reduction candidate for 6,8
G2: 7 => CTR
* 3218745696953217488745961234..2598..95.14.23621....49576891235413.4.5...54.......
* PAIR RESTART
* PAIR D1: 6,8 COL D
D4: 6,8,2,7                              # reduction candidate for 6,8
D4: 6,8 => CTR
* 321.745.9.95321......5961234...59.1.95721843621.7438957649.2.511..4.5...5..1.7...
D4: 2,7 => SOLVED
* 321674589895321647674598123436259718958147236217836495763912854189465372542783961
* DURATION: 0:00:08.363006  START: 19:49:30.980222  END: 19:49:39.343228 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-500-base-pr-001.dot
* REASONING
* DIS # A3: 7 => CTR => A3: 6,8
* DIS A3: 6,8 # H2: 6,8 => CTR => H2: 4,7
* DIS A3: 6,8 + H2: 4,7 # G2: 7 => CTR => G2: 6,8
* DIS A3: 6,8 + H2: 4,7 + G2: 6,8 # D4: 6,8 => CTR => D4: 2,7
* PRF A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7 => SOL
* STA A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7
* CNT   5 HDP CHAINS /   7 HYP OPENED

Header Info

Top 500 Minimum 17 500

solution: 321674589895321647674598123436259718958147236217836495763912854189465372542783961
info: 97182    FNBTHYK  S8.f     16638

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

Solution

position: 321674589895321647674598123436259718958147236217836495763912854189465372542783961 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:

* INC # A3: 6,8 => UNS
* DIS # A3: 7 => CTR => A3: 6,8
* INC # G2: 6,8 => UNS
* DIS # H2: 6,8 => CTR => H2: 4,7
* INC # H2: 4,7 => UNS
* DIS # D4: 6,8 => CTR => D4: 2,7
* PRF # D4: 2,7 => SOL
* PRF # D6: 6,8 => SOL
* DIS # D6: 7 => CTR => D6: 6,8
* DIS # D9: 6,8 => CTR => D9: 1,7
* INC # D9: 1,7 => UNS
* INC # A3: 6,8 => UNS
* DIS # A3: 7 => CTR => A3: 6,8
* PRF # F6: 6,8 => SOL
* INC # F6: 3,7 => UNS
* DIS # F9: 6,8 => CTR => F9: 3,7
* INC # F9: 3,7 => UNS
* INC # G2: 6,8 => UNS
* DIS # H2: 6,8 => CTR => H2: 4,7
* INC # H2: 4,7 => UNS
* INC # H8: 6,8 => UNS
* INC # H9: 6,8 => UNS
* DIS # B4: 7,8 => CTR => B4: 3
* PRF # B4: 3 => SOL
* DIS # C4: 7,8 => CTR => C4: 3,6
* INC # C4: 3,6 => UNS
* PRF # C6: 7,8 => SOL
* DIS # C6: 6 => CTR => C6: 7,8
* DIS # C3: 7,8 => CTR => C3: 4
* PRF # C3: 4 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* INC # C7: 3,4 => UNS
* DIS # D4: 7,8 => CTR => D4: 2,6
* INC # D4: 2,6 => UNS
* INC # D6: 7,8 => UNS
* DIS # F6: 7,8 => CTR => F6: 3,6
* INC # F6: 3,6 => UNS
* DIS # F9: 7,8 => CTR => F9: 3,6
* PRF # F9: 3,6 => SOL
* DIS # C7: 7,8 => CTR => C7: 3,4
* INC # C7: 3,4 => UNS
* INC # B8: 7,8 => UNS
* PRF # G7: 7,8 => SOL
* DIS # G7: 3 => CTR => G7: 7,8
* DIS # I7: 7,8 => CTR => I7: 1,4
* INC # I7: 1,4 => UNS
* DIS # A3: 7,8 => CTR => A3: 6
* PRF # A3: 6 => SOL
* INC # G8: 2,9 => UNS
* INC # G8: 3,6,7,8 => UNS
* INC # G9: 2,9 => UNS
* INC # G9: 3,6,8 => UNS
* CNT  52 HDP CHAINS /  52 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 6,8 => UNS
* DIS # A3: 7 => CTR => A3: 6,8
* INC A3: 6,8 # G2: 6,8 => UNS
* DIS A3: 6,8 # H2: 6,8 => CTR => H2: 4,7
* INC A3: 6,8 + H2: 4,7 # G2: 6,8 => UNS
* DIS A3: 6,8 + H2: 4,7 # G2: 7 => CTR => G2: 6,8
* DIS A3: 6,8 + H2: 4,7 + G2: 6,8 # D4: 6,8 => CTR => D4: 2,7
* PRF A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7 => SOL
* STA A3: 6,8 + H2: 4,7 + G2: 6,8 + D4: 2,7
* CNT   8 HDP CHAINS /   7 HYP OPENED