Analysis of xx-top500-290-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .68...3.....7.1.............3..8.6..7......4..........1..4...574...6.......2..... initial

Autosolve

position: .68...371.4.7.1.86...8.64...34.8761.78.6...436..3..7.81264938574..168.3.893275164 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A2: 2,5 => CTR => A2: 3,9
* DIS # A3: 2,5 => CTR => A3: 3,9
* DIS # A4: 9 => CTR => A4: 2,5
* DIS # I3: 2,9 => CTR => I3: 5
* PRF # A4: 5,9 => SOL
* DIS # A4: 2 => CTR => A4: 5,9
* DIS # I4: 5,9 => CTR => I4: 2
* PRF # I4: 2 => SOL
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # I3: 2,9 => CTR => I3: 5
* CNT  12 HDP CHAINS /  40 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 # A2: 2,5 => CTR => A2: 3,9
* DIS A2: 3,9 # A3: 2,5 => CTR => A3: 3,9
* DIS A2: 3,9 + A3: 3,9 # E1: 2,5 => CTR => E1: 4
* DIS A2: 3,9 + A3: 3,9 + E1: 4 # I3: 2,9 => CTR => I3: 5
* DIS A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 # C6: 1,5 => CTR => C6: 2,9
* PRF A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 # E2: 2,5 => SOL
* STA A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 + E2: 2,5
* CNT   6 HDP CHAINS /   8 HYP OPENED

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

Details

Positions

.68...3.....7.1.............3..8.6..7......4..........1..4...574...6.......2..... initial
.68...371.4.7.1.86...8.64...34.8761.78.6...436..3..7.81264938574..168.3.893275164 autosolve
268549371345721986971836425534987612789612543612354798126493857457168239893275164 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
A1: 2,5
B3: 1,7
C3: 1,7
D1: 5,9
H3: 2,9
B6: 1,5
D4: 5,9
F5: 2,9
H6: 2,9
B8: 5,7
C8: 5,7
G8: 2,9
I8: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B3,C3: 1.. / B3 = 1  => 10 pairs (_) / C3 = 1  =>  8 pairs (_)
E5,E6: 1.. / E5 = 1  => 13 pairs (_) / E6 = 1  => 14 pairs (_)
C5,E5: 1.. / C5 = 1  => 14 pairs (_) / E5 = 1  => 13 pairs (_)
B3,B6: 1.. / B3 = 1  => 10 pairs (_) / B6 = 1  =>  8 pairs (_)
G8,I8: 2.. / G8 = 2  => 16 pairs (_) / I8 = 2  =>  0 pairs (X)
A4,I4: 2.. / A4 = 2  =>  0 pairs (X) / I4 = 2  =>  0 pairs (_)
H3,H6: 2.. / H3 = 2  => 17 pairs (_) / H6 = 2  =>  0 pairs (X)
A2,A3: 3.. / A2 = 3  => 14 pairs (_) / A3 = 3  => 15 pairs (_)
E2,E3: 3.. / E2 = 3  => 15 pairs (_) / E3 = 3  => 14 pairs (_)
A2,E2: 3.. / A2 = 3  => 14 pairs (_) / E2 = 3  => 15 pairs (_)
A3,E3: 3.. / A3 = 3  => 15 pairs (_) / E3 = 3  => 14 pairs (_)
E1,F1: 4.. / E1 = 4  => 14 pairs (_) / F1 = 4  => 22 pairs (_)
E6,F6: 4.. / E6 = 4  => 22 pairs (_) / F6 = 4  => 14 pairs (_)
E1,E6: 4.. / E1 = 4  => 14 pairs (_) / E6 = 4  => 22 pairs (_)
F1,F6: 4.. / F1 = 4  => 22 pairs (_) / F6 = 4  => 14 pairs (_)
G2,I3: 5.. / G2 = 5  =>  0 pairs (X) / I3 = 5  => 17 pairs (_)
I4,G5: 5.. / I4 = 5  =>  0 pairs (X) / G5 = 5  => 17 pairs (_)
B8,C8: 5.. / B8 = 5  =>  8 pairs (_) / C8 = 5  => 10 pairs (_)
B6,B8: 5.. / B6 = 5  => 10 pairs (_) / B8 = 5  =>  8 pairs (_)
D1,D4: 5.. / D1 = 5  =>  0 pairs (*) / D4 = 5  =>  0 pairs (X)
G2,G5: 5.. / G2 = 5  =>  0 pairs (X) / G5 = 5  => 17 pairs (_)
I3,I4: 5.. / I3 = 5  => 17 pairs (_) / I4 = 5  =>  0 pairs (X)
B3,C3: 7.. / B3 = 7  =>  8 pairs (_) / C3 = 7  => 10 pairs (_)
B8,C8: 7.. / B8 = 7  => 10 pairs (_) / C8 = 7  =>  8 pairs (_)
B3,B8: 7.. / B3 = 7  =>  8 pairs (_) / B8 = 7  => 10 pairs (_)
C3,C8: 7.. / C3 = 7  => 10 pairs (_) / C8 = 7  =>  8 pairs (_)
D1,F1: 9.. / D1 = 9  => 20 pairs (_) / F1 = 9  =>  0 pairs (*)
G8,I8: 9.. / G8 = 9  =>  0 pairs (X) / I8 = 9  => 16 pairs (_)
D1,D4: 9.. / D1 = 9  => 20 pairs (_) / D4 = 9  =>  0 pairs (*)
H3,H6: 9.. / H3 = 9  =>  0 pairs (X) / H6 = 9  => 17 pairs (_)
* DURATION: 0:00:53.348310  START: 12:51:39.351637  END: 12:52:32.699947 2017-05-04
* CP COUNT: (30)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B3,B6,B8,C3,C8,D1,D4,F5,G8,H3,H6,I8)
* .68...371.4.7.1.86...8.64...34.8761.78.6...436..3..7.81264938574..168.3.893275164
* PAIR A1: 2,5 BLK 1
A2: 2,5,3,9                              # reduction candidate for 2,5
A2: 2,5 => CTR
* .68...371.4.731.863..8.64..93458761278.6..5436..3..7981264938574..168239893275164
A2: 3,9                                  # 14 pairs
C2: 2,5,9                                # reduction candidate for 2,5
C2: 2,5                                  # 17 pairs
A3: 2,5,3,9                              # reduction candidate for 2,5
A3: 2,5 => CTR
* .68...3713497.1.86...8364..93458761278.6..5436..3..7981264938574..168.3.893275164
A3: 3,9                                  # 14 pairs
* PAIR A1: 2,5 ROW 1
E1: 2,5,4                                # reduction candidate for 2,5
E1: 2,5                                  # 22 pairs
E1: 4                                    # 14 pairs
* PAIR A1: 2,5 COL A
A4: 2,5,9                                # reduction candidate for 2,5
A4: 9 => CTR
* .68...371.4.7.1.86...8.64..93458761278.6..5436..3..7981264938574..168239893275164
A4: 2,5                                  # 17 pairs
* PAIR H3: 2,9 BLK 3
G2: 2,9,5                                # reduction candidate for 2,9
G2: 2,9                                  # 17 pairs
I3: 2,9,5                                # reduction candidate for 2,9
I3: 2,9 => CTR
* .685.9371.4.7.15865..8364..234.8761578.6...436..3..7.81264938574..168.3.893275164
I3: 5                                    # 17 pairs
* PAIR H3: 2,9 ROW 3
A3: 2,9,3,5                              # reduction candidate for 2,9
A3: 2,9                                  # 18 pairs
A3: 3,5                                  # 15 pairs
* PAIR B6: 1,5 BLK 4
C5: 1,5,2,9                              # reduction candidate for 1,5
C5: 1,5                                  # 20 pairs
C6: 1,5,2,9                              # reduction candidate for 1,5
C6: 1,5                                  # 22 pairs
* PAIR B6: 1,5 ROW 6
E6: 1,5,2,4                              # reduction candidate for 1,5
E6: 2,4                                  # 22 pairs
E6: 1,5                                  # 17 pairs
* PAIR D4: 5,9 ROW 4
A4: 5,9,2                                # reduction candidate for 5,9
A4: 5,9 => SOLVED
* 268549371345721986971836425534987612789612543612354798126493857457168239893275164
A4: 2 => CTR
* 5689..371.427.1.86...8.64..23458761978.6..5436..3..7281264938574..168.3.893275164
I4: 5,9,2                                # reduction candidate for 5,9
I4: 5,9 => CTR
* 5689..371.427.1.86...8.64..23458761978.6..5436..3..7281264938574..168.3.893275164
I4: 2 => SOLVED
* 268549371345721986971836425534987612789612543612354798126493857457168239893275164
* PAIR F5: 2,9 BLK 5
F6: 2,9,4                                # reduction candidate for 2,9
F6: 2,9                                  # 22 pairs
F6: 4                                    # 14 pairs
* PAIR F5: 2,9 ROW 5
C5: 2,9,1,5                              # reduction candidate for 2,9
C5: 2,9                                  # 17 pairs
G5: 2,9,5                                # reduction candidate for 2,9
G5: 2,9 => CTR
* .685.9371.4.7.15865..8364..234.8761578.6...436..3..7.81264938574..168.3.893275164
G5: 5                                    # 17 pairs
* PAIR F5: 2,9 COL F
F1: 2,9,4                                # reduction candidate for 2,9
F1: 4                                    # 22 pairs
F1: 2,9                                  # 14 pairs
* PAIR H6: 2,9 BLK 6
I4: 2,9,5                                # reduction candidate for 2,9
I4: 2,9                                  # 17 pairs
G5: 2,9,5                                # reduction candidate for 2,9
G5: 2,9 => CTR
* .685.9371.4.7.15865..8364..234.8761578.6...436..3..7.81264938574..168.3.893275164
G5: 5                                    # 17 pairs
* PAIR H6: 2,9 ROW 6
C6: 2,9,1,5                              # reduction candidate for 2,9
C6: 2,9                                  # 17 pairs
F6: 2,9,4                                # reduction candidate for 2,9
F6: 2,9                                  # 22 pairs
* PAIR G8: 2,9 COL G
G2: 2,9,5                                # reduction candidate for 2,9
G2: 2,9                                  # 17 pairs
G5: 2,9,5                                # reduction candidate for 2,9
G5: 2,9 => CTR
* .685.9371.4.7.15865..8364..234.8761578.6...436..3..7.81264938574..168.3.893275164
G5: 5                                    # 17 pairs
* PAIR I8: 2,9 COL I
I3: 2,9,5                                # reduction candidate for 2,9
I3: 2,9 => CTR
* .685.9371.4.7.15865..8364..234.8761578.6...436..3..7.81264938574..168.3.893275164
I3: 5                                    # 17 pairs
I4: 2,9,5                                # reduction candidate for 2,9
I4: 2,9                                  # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-290-base-pr-000.dot
* REASONING
* DIS # A2: 2,5 => CTR => A2: 3,9
* DIS # A3: 2,5 => CTR => A3: 3,9
* DIS # A4: 9 => CTR => A4: 2,5
* DIS # I3: 2,9 => CTR => I3: 5
* PRF # A4: 5,9 => SOL
* DIS # A4: 2 => CTR => A4: 5,9
* DIS # I4: 5,9 => CTR => I4: 2
* PRF # I4: 2 => SOL
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # G5: 2,9 => CTR => G5: 5
* DIS # I3: 2,9 => CTR => I3: 5
* CNT  12 HDP CHAINS /  40 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B3,B6,B8,C3,C8,D1,D4,F5,G8,H3,H6,I8)
* .68...371.4.7.1.86...8.64...34.8761.78.6...436..3..7.81264938574..168.3.893275164
* PAIR A1: 2,5 BLK 1
A2: 2,5,3,9                              # reduction candidate for 2,5
A2: 2,5 => CTR
* .68...371.4.731.863..8.64..93458761278.6..5436..3..7981264938574..168239893275164
C2: 2,5,9                                # reduction candidate for 2,5
C2: 2,5                                  # 17 pairs
A3: 2,5,3,9                              # reduction candidate for 2,5
A3: 2,5 => CTR
* .68...3713497.1.86...8364..93458761278.6..5436..3..7981264938574..168.3.893275164
* RESTART
* PAIR A1: 2,5 ROW 1
E1: 2,5,4                                # reduction candidate for 2,5
E1: 2,5 => CTR
* 5689243719427.1.86...8.64...3458761978.61.5436..34.7281264938574..168932893275164
* PAIR RESTART
* PAIR H3: 2,9 BLK 3
G2: 2,9,5                                # reduction candidate for 2,9
G2: 2,9                                  # 22 pairs
I3: 2,9,5                                # reduction candidate for 2,9
I3: 2,9 => CTR
* .68.4.371.4.7.1586...8564...345876197856192436..3.47.81264938574..168.3.893275164
* RESTART
* PAIR B6: 1,5 BLK 4
C6: 1,5,2,9                              # reduction candidate for 1,5
C6: 1,5 => CTR
* .68.4.371.4.7.1.86...8.64.5.34.8761.7896125436..3547.81264938574..168.3.893275164

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A1,A2,A3,A4,B3,B6,B8,C2,C3,C5,C6,C8,D1,D4,E3,E5,E6,F1,F5,G2,G8,H3,H6,I4,I8)
* .68.4.371.4.7.1.86...8.64.5.34.8761.78.6..5436..3.47.81264938574..168.3.893275164
* PAIR C2: 2,5 ROW 2
E2: 2,5,3                                # reduction candidate for 2,5
E2: 2,5 => SOLVED
* 268549371345721986971836425534987612789612543612354798126493857457168239893275164
* DURATION: 0:00:12.167709  START: 12:53:11.138281  END: 12:53:23.305990 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-290-base-pr-001.dot
* REASONING
* DIS # A2: 2,5 => CTR => A2: 3,9
* DIS A2: 3,9 # A3: 2,5 => CTR => A3: 3,9
* DIS A2: 3,9 + A3: 3,9 # E1: 2,5 => CTR => E1: 4
* DIS A2: 3,9 + A3: 3,9 + E1: 4 # I3: 2,9 => CTR => I3: 5
* DIS A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 # C6: 1,5 => CTR => C6: 2,9
* PRF A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 # E2: 2,5 => SOL
* STA A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 + E2: 2,5
* CNT   6 HDP CHAINS /   8 HYP OPENED

Header Info

Top 500 Minimum 17 290

solution: 268549371345721986971836425534987612789612543612354798126493857457168239893275164
info: 2397     FNBHWXY  S8.f     21970

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

Solution

position: 268549371345721986971836425534987612789612543612354798126493857457168239893275164 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 # A2: 2,5 => CTR => A2: 3,9
* INC # A2: 3,9 => UNS
* INC # C2: 2,5 => UNS
* DIS # A3: 2,5 => CTR => A3: 3,9
* INC # A3: 3,9 => UNS
* INC # E1: 2,5 => UNS
* INC # E1: 4 => UNS
* INC # A4: 2,5 => UNS
* DIS # A4: 9 => CTR => A4: 2,5
* INC # G2: 2,9 => UNS
* DIS # I3: 2,9 => CTR => I3: 5
* INC # I3: 5 => UNS
* INC # A3: 2,9 => UNS
* INC # A3: 3,5 => UNS
* INC # C5: 1,5 => UNS
* INC # C6: 1,5 => UNS
* INC # E6: 1,5 => UNS
* INC # E6: 2,4 => UNS
* PRF # A4: 5,9 => SOL
* DIS # A4: 2 => CTR => A4: 5,9
* DIS # I4: 5,9 => CTR => I4: 2
* PRF # I4: 2 => SOL
* INC # F6: 2,9 => UNS
* INC # F6: 4 => UNS
* INC # C5: 2,9 => UNS
* DIS # G5: 2,9 => CTR => G5: 5
* INC # G5: 5 => UNS
* INC # F1: 2,9 => UNS
* INC # F1: 4 => UNS
* INC # I4: 2,9 => UNS
* DIS # G5: 2,9 => CTR => G5: 5
* INC # G5: 5 => UNS
* INC # C6: 2,9 => UNS
* INC # F6: 2,9 => UNS
* INC # G2: 2,9 => UNS
* DIS # G5: 2,9 => CTR => G5: 5
* INC # G5: 5 => UNS
* DIS # I3: 2,9 => CTR => I3: 5
* INC # I3: 5 => UNS
* INC # I4: 2,9 => UNS
* CNT  40 HDP CHAINS /  40 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A2: 2,5 => CTR => A2: 3,9
* INC A2: 3,9 # C2: 2,5 => UNS
* DIS A2: 3,9 # A3: 2,5 => CTR => A3: 3,9
* DIS A2: 3,9 + A3: 3,9 # E1: 2,5 => CTR => E1: 4
* INC A2: 3,9 + A3: 3,9 + E1: 4 # G2: 2,9 => UNS
* DIS A2: 3,9 + A3: 3,9 + E1: 4 # I3: 2,9 => CTR => I3: 5
* DIS A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 # C6: 1,5 => CTR => C6: 2,9
* PRF A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 # E2: 2,5 => SOL
* STA A2: 3,9 + A3: 3,9 + E1: 4 + I3: 5 + C6: 2,9 + E2: 2,5
* CNT   8 HDP CHAINS /   8 HYP OPENED