Analysis of xx-top500-256-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....5.2.861............9.....74...1.3...2.......6...4.2.....5.....1.7............ initial

Autosolve

position: 79435126861..74.......69174.6749..1234172....9..61.74.27.9465.14591.7.2.1.65.2497 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* PRF # C3: 5,8 => SOL
* DIS # C3: 2,3 => CTR => C3: 5,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* DIS # I2: 3,9 => CTR => I2: 5
* PRF # I2: 5 => SOL
* DIS # I2: 9 => CTR => I2: 3,5
* DIS # C6: 2 => CTR => C6: 5,8
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # F6: 5,8 => SOL
* DIS # F6: 3 => CTR => F6: 5,8
* PRF # F4: 3,8 => SOL
* DIS # F4: 5 => CTR => F4: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # F6: 3,5 => SOL
* DIS # F6: 8 => CTR => F6: 3,5
* DIS # I2: 9 => CTR => I2: 3,5
* DIS # C3: 3,8 => CTR => C3: 2,5
* PRF # C3: 2,5 => SOL
* DIS # B3: 2 => CTR => B3: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # G8: 3,6 => SOL
* DIS # G8: 8 => CTR => G8: 3,6
* CNT  37 HDP CHAINS /  46 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 # B3: 2,8 => CTR => B3: 3
* PRF B3: 3 => SOL
* STA B3: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

....5.2.861............9.....74...1.3...2.......6...4.2.....5.....1.7............ initial
79435126861..74.......69174.6749..1234172....9..61.74.27.9465.14591.7.2.1.65.2497 autosolve
794351268612874935835269174567493812341728659928615743273946581459187326186532497 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (20)
C2: 2,8
A3: 5,8
D2: 2,8
D3: 2,8
G2: 3,9
H2: 3,5
A4: 5,8
B6: 2,8
F5: 5,8
G4: 3,8
G5: 6,9
H5: 5,8
I5: 6,9
I6: 3,5
C7: 3,8
B9: 3,8
E8: 3,8
E9: 3,8
H7: 3,8
I8: 3,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D2,D3: 2.. / D2 = 2  =>  0 pairs (X) / D3 = 2  => 18 pairs (_)
B6,C6: 2.. / B6 = 2  => 21 pairs (_) / C6 = 2  =>  0 pairs (X)
C2,D2: 2.. / C2 = 2  => 18 pairs (_) / D2 = 2  =>  0 pairs (X)
B3,B6: 2.. / B3 = 2  =>  0 pairs (X) / B6 = 2  => 21 pairs (_)
B3,C3: 3.. / B3 = 3  =>  0 pairs (*) / C3 = 3  =>  0 pairs (X)
F4,F6: 3.. / F4 = 3  =>  0 pairs (*) / F6 = 3  =>  0 pairs (X)
G4,I6: 3.. / G4 = 3  =>  0 pairs (X) / I6 = 3  =>  0 pairs (_)
C7,B9: 3.. / C7 = 3  =>  0 pairs (*) / B9 = 3  =>  0 pairs (X)
E8,E9: 3.. / E8 = 3  =>  0 pairs (X) / E9 = 3  =>  0 pairs (_)
F4,G4: 3.. / F4 = 3  =>  0 pairs (*) / G4 = 3  =>  0 pairs (X)
F6,I6: 3.. / F6 = 3  =>  0 pairs (X) / I6 = 3  =>  0 pairs (_)
C7,H7: 3.. / C7 = 3  =>  0 pairs (*) / H7 = 3  =>  0 pairs (X)
B9,E9: 3.. / B9 = 3  =>  0 pairs (X) / E9 = 3  =>  0 pairs (_)
B3,B9: 3.. / B3 = 3  =>  0 pairs (*) / B9 = 3  =>  0 pairs (X)
C3,C7: 3.. / C3 = 3  =>  0 pairs (X) / C7 = 3  =>  0 pairs (_)
H2,H7: 3.. / H2 = 3  =>  0 pairs (*) / H7 = 3  =>  0 pairs (X)
A3,C3: 5.. / A3 = 5  =>  0 pairs (X) / C3 = 5  =>  0 pairs (_)
H2,I2: 5.. / H2 = 5  =>  0 pairs (X) / I2 = 5  =>  0 pairs (_)
A4,C6: 5.. / A4 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
H5,I6: 5.. / H5 = 5  =>  0 pairs (*) / I6 = 5  =>  0 pairs (X)
A4,F4: 5.. / A4 = 5  =>  0 pairs (*) / F4 = 5  =>  0 pairs (X)
F5,H5: 5.. / F5 = 5  =>  0 pairs (X) / H5 = 5  =>  0 pairs (_)
A3,A4: 5.. / A3 = 5  =>  0 pairs (X) / A4 = 5  =>  0 pairs (_)
C3,C6: 5.. / C3 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
H2,H5: 5.. / H2 = 5  =>  0 pairs (X) / H5 = 5  =>  0 pairs (_)
I2,I6: 5.. / I2 = 5  =>  0 pairs (*) / I6 = 5  =>  0 pairs (X)
G5,I5: 6.. / G5 = 6  => 18 pairs (_) / I5 = 6  =>  0 pairs (X)
G8,I8: 6.. / G8 = 6  =>  0 pairs (X) / I8 = 6  => 18 pairs (_)
G5,G8: 6.. / G5 = 6  => 18 pairs (_) / G8 = 6  =>  0 pairs (X)
I5,I8: 6.. / I5 = 6  =>  0 pairs (X) / I8 = 6  => 18 pairs (_)
D2,D3: 8.. / D2 = 8  => 18 pairs (_) / D3 = 8  =>  0 pairs (X)
G4,H5: 8.. / G4 = 8  =>  0 pairs (*) / H5 = 8  =>  0 pairs (X)
C7,B9: 8.. / C7 = 8  =>  0 pairs (X) / B9 = 8  =>  0 pairs (_)
E8,E9: 8.. / E8 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
H7,G8: 8.. / H7 = 8  =>  0 pairs (*) / G8 = 8  =>  0 pairs (X)
C2,D2: 8.. / C2 = 8  =>  0 pairs (X) / D2 = 8  => 18 pairs (_)
F5,H5: 8.. / F5 = 8  =>  0 pairs (*) / H5 = 8  =>  0 pairs (X)
C7,H7: 8.. / C7 = 8  =>  0 pairs (X) / H7 = 8  =>  0 pairs (_)
E8,G8: 8.. / E8 = 8  =>  0 pairs (*) / G8 = 8  =>  0 pairs (X)
B9,E9: 8.. / B9 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
A3,A4: 8.. / A3 = 8  =>  0 pairs (*) / A4 = 8  =>  0 pairs (X)
G4,G8: 8.. / G4 = 8  =>  0 pairs (*) / G8 = 8  =>  0 pairs (X)
H5,H7: 8.. / H5 = 8  =>  0 pairs (X) / H7 = 8  =>  0 pairs (_)
G2,I2: 9.. / G2 = 9  => 18 pairs (_) / I2 = 9  =>  0 pairs (X)
G5,I5: 9.. / G5 = 9  =>  0 pairs (X) / I5 = 9  => 18 pairs (_)
G2,G5: 9.. / G2 = 9  => 18 pairs (_) / G5 = 9  =>  0 pairs (X)
I2,I5: 9.. / I2 = 9  =>  0 pairs (X) / I5 = 9  => 18 pairs (_)
* DURATION: 0:01:15.255425  START: 11:32:10.416691  END: 11:33:25.672116 2017-05-04
* CP COUNT: (47)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B6,B9,C2,C7,D2,D3,E8,E9,F5,G2,G4,G5,H2,H5,H7,I5,I6,I8)
* 79435126861..74.......69174.6749..1234172....9..61.74.27.9465.14591.7.2.1.65.2497
* PAIR C2: 2,8 BLK 1
B3: 2,8,3                                # reduction candidate for 2,8
B3: 2,8 => CTR
* 79435126861..74.....3.69174.6749..1234172....9.561.7432789465314591.7.2.1.65.2497
B3: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
C3: 2,8,3,5                              # reduction candidate for 2,8
C3: 2,8 => CTR
* 79435126861..74...53..6917486749531234172....9..61.74.27.9465.14591.7.2.1.65.2497
C3: 3,5                                  # 21 pairs
* PAIR C2: 2,8 COL C
C6: 2,8,5                                # reduction candidate for 2,8
C6: 2,8 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
C6: 5 => CTR
* 79435126861..74.......69174.6749..1234172....92561874327.9465.14591.7.2.1.65.2497
* PAIR A3: 5,8 BLK 1
C3: 5,8,2,3                              # reduction candidate for 5,8
C3: 5,8 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
C3: 2,3 => CTR
* 79435126861..74...5...6917486749531234172....9..61.74.27.9465.14591.7.2.1.65.2497
* PAIR D3: 2,8 ROW 3
B3: 2,8,3                                # reduction candidate for 2,8
B3: 2,8 => CTR
* 79435126861..74.....3.69174.6749..1234172....9.561.7432789465314591.7.2.1.65.2497
B3: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
C3: 2,8,3,5                              # reduction candidate for 2,8
C3: 2,8 => CTR
* 79435126861..74...53..6917486749531234172....9..61.74.27.9465.14591.7.2.1.65.2497
C3: 3,5                                  # 21 pairs
* PAIR G2: 3,9 BLK 3
I2: 3,9,5                                # reduction candidate for 3,9
I2: 3,9 => CTR
* 79435126861..74.5.....69174.6749..12341725.8.9..61.745278946531459137826136582497
I2: 5 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
* PAIR H2: 3,5 BLK 3
I2: 3,5,9                                # reduction candidate for 3,5
I2: 9 => CTR
* 79435126861..74.59....69174.6749..123417259869..61.7452789465314591.7.2.1.65.2497
I2: 3,5                                  # 18 pairs
* PAIR A4: 5,8 BLK 4
C6: 5,8,2                                # reduction candidate for 5,8
C6: 2 => CTR
* 79435126861..74.....5.6917456749..1234172....98261.74.27.9465.14591.7.2.1.65.2497
C6: 5,8                                  # 21 pairs
* PAIR A4: 5,8 ROW 4
F4: 5,8,3                                # reduction candidate for 5,8
F4: 5,8 => CTR
* 79435126861..74.......69174.6749.31234172..8.9..613745278946531459137826136582497
F4: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
* PAIR B6: 2,8 BLK 4
C6: 2,8,5                                # reduction candidate for 2,8
C6: 2,8 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
C6: 5 => CTR
* 79435126861..74.......69174.6749..1234172....92561874327.9465.14591.7.2.1.65.2497
* PAIR B6: 2,8 COL B
B3: 2,8,3                                # reduction candidate for 2,8
B3: 2,8 => CTR
* 79435126861..74.....3.69174.6749..1234172....9.561.7432789465314591.7.2.1.65.2497
B3: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
* PAIR F5: 5,8 BLK 5
F4: 5,8,3                                # reduction candidate for 5,8
F4: 5,8 => CTR
* 79435126861..74.......69174.6749.31234172..8.9..613745278946531459137826136582497
F4: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
F6: 5,8,3                                # reduction candidate for 5,8
F6: 5,8 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
F6: 3 => CTR
* 79435126861..74.5...5.69174567498312341725.8.9..61374527.9465.14591.7.2.1.65.2497
* PAIR G4: 3,8 ROW 4
F4: 3,8,5                                # reduction candidate for 3,8
F4: 3,8 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
F4: 5 => CTR
* 79435126861..74.......69174.67495312341728...9..61.74.27.9465.14591.7.2.1.65.2497
* PAIR G4: 3,8 COL G
G8: 3,8,6                                # reduction candidate for 3,8
G8: 6 => CTR
* 79435126861..74.......69174.6749.812341728.5.9..61.74327.9465.14591.7.2.1.65.2497
G8: 3,8                                  # 18 pairs
* PAIR I6: 3,5 ROW 6
F6: 3,5,8                                # reduction candidate for 3,5
F6: 3,5 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
F6: 8 => CTR
* 79435126861..74.......69174.6749381234172....9..61.74.27.9465.14591.7.2.1.65.2497
* PAIR I6: 3,5 COL I
I2: 3,5,9                                # reduction candidate for 3,5
I2: 9 => CTR
* 79435126861..74.59....69174.6749..123417259869..61.7452789465314591.7.2.1.65.2497
I2: 3,5                                  # 18 pairs
* PAIR C7: 3,8 COL C
C3: 3,8,2,5                              # reduction candidate for 3,8
C3: 3,8 => CTR
* 79435126861..74...5...6917486749531234172....9..61.74.27.9465.14591.7.2.1.65.2497
C3: 2,5 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
* PAIR B9: 3,8 COL B
B3: 3,8,2                                # reduction candidate for 3,8
B3: 2 => CTR
* 79435126861..74....2386917486749..1234172....9..61.74.27.9465.14591.7.2.1.65.2497
B3: 3,8                                  # 21 pairs
* PAIR E8: 3,8 ROW 8
G8: 3,8,6                                # reduction candidate for 3,8
G8: 6 => CTR
* 79435126861..74.......69174.6749.812341728.5.9..61.74327.9465.14591.7.2.1.65.2497
G8: 3,8                                  # 18 pairs
* PAIR H7: 3,8 BLK 9
G8: 3,8,6                                # reduction candidate for 3,8
G8: 6 => CTR
* 79435126861..74.......69174.6749.812341728.5.9..61.74327.9465.14591.7.2.1.65.2497
G8: 3,8                                  # 18 pairs
* PAIR I8: 3,6 BLK 9
G8: 3,6,8                                # reduction candidate for 3,6
G8: 3,6 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
G8: 8 => CTR
* 79435126861..749......69174.6749.31234172.6899..613745278946531459137826136582497
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-256-base-pr-000.dot
* REASONING
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* PRF # C3: 5,8 => SOL
* DIS # C3: 2,3 => CTR => C3: 5,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* DIS # I2: 3,9 => CTR => I2: 5
* PRF # I2: 5 => SOL
* DIS # I2: 9 => CTR => I2: 3,5
* DIS # C6: 2 => CTR => C6: 5,8
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # F6: 5,8 => SOL
* DIS # F6: 3 => CTR => F6: 5,8
* PRF # F4: 3,8 => SOL
* DIS # F4: 5 => CTR => F4: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # F6: 3,5 => SOL
* DIS # F6: 8 => CTR => F6: 3,5
* DIS # I2: 9 => CTR => I2: 3,5
* DIS # C3: 3,8 => CTR => C3: 2,5
* PRF # C3: 2,5 => SOL
* DIS # B3: 2 => CTR => B3: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # G8: 3,6 => SOL
* DIS # G8: 8 => CTR => G8: 3,6
* CNT  37 HDP CHAINS /  46 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B6,B9,C2,C7,D2,D3,E8,E9,F5,G2,G4,G5,H2,H5,H7,I5,I6,I8)
* 79435126861..74.......69174.6749..1234172....9..61.74.27.9465.14591.7.2.1.65.2497
* PAIR C2: 2,8 BLK 1
B3: 2,8,3                                # reduction candidate for 2,8
B3: 2,8 => CTR
* 79435126861..74.....3.69174.6749..1234172....9.561.7432789465314591.7.2.1.65.2497
B3: 3 => SOLVED
* 794351268612874935835269174567493812341728659928615743273946581459187326186532497
* DURATION: 0:00:01.530263  START: 11:34:12.148005  END: 11:34:13.678268 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-256-base-pr-001.dot
* REASONING
* DIS # B3: 2,8 => CTR => B3: 3
* PRF B3: 3 => SOL
* STA B3: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 256

solution: 794351268612874935835269174567493812341728659928615743273946581459187326186532497
info: 2078     FNBTWXY  S8.f     4830

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

Solution

position: 794351268612874935835269174567493812341728659928615743273946581459187326186532497 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 # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* INC # C3: 3,5 => UNS
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* PRF # C3: 5,8 => SOL
* DIS # C3: 2,3 => CTR => C3: 5,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # C3: 2,8 => CTR => C3: 3,5
* INC # C3: 3,5 => UNS
* DIS # I2: 3,9 => CTR => I2: 5
* PRF # I2: 5 => SOL
* INC # I2: 3,5 => UNS
* DIS # I2: 9 => CTR => I2: 3,5
* INC # C6: 5,8 => UNS
* DIS # C6: 2 => CTR => C6: 5,8
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # C6: 2,8 => SOL
* DIS # C6: 5 => CTR => C6: 2,8
* DIS # B3: 2,8 => CTR => B3: 3
* PRF # B3: 3 => SOL
* DIS # F4: 5,8 => CTR => F4: 3
* PRF # F4: 3 => SOL
* PRF # F6: 5,8 => SOL
* DIS # F6: 3 => CTR => F6: 5,8
* PRF # F4: 3,8 => SOL
* DIS # F4: 5 => CTR => F4: 3,8
* INC # G8: 3,8 => UNS
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # F6: 3,5 => SOL
* DIS # F6: 8 => CTR => F6: 3,5
* INC # I2: 3,5 => UNS
* DIS # I2: 9 => CTR => I2: 3,5
* DIS # C3: 3,8 => CTR => C3: 2,5
* PRF # C3: 2,5 => SOL
* INC # B3: 3,8 => UNS
* DIS # B3: 2 => CTR => B3: 3,8
* INC # G8: 3,8 => UNS
* DIS # G8: 6 => CTR => G8: 3,8
* INC # G8: 3,8 => UNS
* DIS # G8: 6 => CTR => G8: 3,8
* PRF # G8: 3,6 => SOL
* DIS # G8: 8 => CTR => G8: 3,6
* CNT  46 HDP CHAINS /  46 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B3: 2,8 => CTR => B3: 3
* PRF B3: 3 => SOL
* STA B3: 3
* CNT   2 HDP CHAINS /   1 HYP OPENED