Analysis of xx-top500-362-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 2...1.5...7.3........4.......4...17......9..38............456....3.......9....... initial

Autosolve

position: 23..1759447539.81.9.145.3.73.45..179.5.1.94838197342.....94563..43.719...9...374. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # C9: 2 => SOL
* DIS # F3: 2 => CTR => F3: 6,8
* DIS # F3: 2 => CTR => F3: 6,8
* PRF # D9: 6,8 => SOL
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* PRF # C5: 6,7 => SOL
* DIS # C5: 2 => CTR => C5: 6,7
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* DIS # F3: 2 => CTR => F3: 6,8
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # C7: 2,8 => CTR => C7: 7
* DIS # I7: 1 => CTR => I7: 2,8
* PRF # D9: 6,8 => SOL
* PRF # C9: 2 => SOL
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* DIS # I8: 2,5 => CTR => I8: 8
* CNT  26 HDP CHAINS /  41 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 # C9: 2 => SOL
* STA C9: 2
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

2...1.5...7.3........4.......4...17......9..38............456....3.......9....... initial
23..1759447539.81.9.145.3.73.45..179.5.1.94838197342.....94563..43.719...9...374. autosolve
238617594475392816961458327324586179756129483819734265187945632643271958592863741 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
C1: 6,8
B3: 6,8
D1: 6,8
F2: 2,6
I2: 2,6
H3: 2,6
B4: 2,6
A5: 6,7
F4: 6,8
E5: 2,6
H6: 5,6
I6: 5,6
A7: 1,7
B7: 2,8
A8: 5,6
A9: 1,5
E9: 6,8
H8: 2,5
I9: 1,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A7,A9: 1.. / A7 = 1  => 18 pairs (_) / A9 = 1  =>  0 pairs (X)
I7,I9: 1.. / I7 = 1  =>  0 pairs (X) / I9 = 1  => 18 pairs (_)
A7,I7: 1.. / A7 = 1  => 18 pairs (_) / I7 = 1  =>  0 pairs (X)
A9,I9: 1.. / A9 = 1  =>  0 pairs (X) / I9 = 1  => 18 pairs (_)
F2,F3: 2.. / F2 = 2  => 14 pairs (_) / F3 = 2  =>  0 pairs (X)
I2,H3: 2.. / I2 = 2  =>  0 pairs (X) / H3 = 2  => 14 pairs (_)
B4,C5: 2.. / B4 = 2  =>  0 pairs (*) / C5 = 2  =>  0 pairs (X)
E4,E5: 2.. / E4 = 2  =>  0 pairs (X) / E5 = 2  =>  0 pairs (_)
D8,D9: 2.. / D8 = 2  =>  0 pairs (*) / D9 = 2  =>  0 pairs (X)
F2,I2: 2.. / F2 = 2  => 14 pairs (_) / I2 = 2  =>  0 pairs (X)
F3,H3: 2.. / F3 = 2  =>  0 pairs (X) / H3 = 2  => 14 pairs (_)
B4,E4: 2.. / B4 = 2  =>  0 pairs (*) / E4 = 2  =>  0 pairs (X)
C5,E5: 2.. / C5 = 2  =>  0 pairs (X) / E5 = 2  =>  0 pairs (_)
C9,D9: 2.. / C9 = 2  =>  0 pairs (*) / D9 = 2  =>  0 pairs (X)
B4,B7: 2.. / B4 = 2  =>  0 pairs (*) / B7 = 2  =>  0 pairs (X)
H3,H8: 2.. / H3 = 2  => 14 pairs (_) / H8 = 2  =>  0 pairs (X)
H6,I6: 5.. / H6 = 5  =>  0 pairs (X) / I6 = 5  => 14 pairs (_)
A8,A9: 5.. / A8 = 5  =>  0 pairs (X) / A9 = 5  => 18 pairs (_)
A9,I9: 5.. / A9 = 5  => 18 pairs (_) / I9 = 5  =>  0 pairs (X)
H6,H8: 5.. / H6 = 5  =>  0 pairs (X) / H8 = 5  => 14 pairs (_)
C1,B3: 6.. / C1 = 6  =>  0 pairs (X) / B3 = 6  =>  0 pairs (_)
I2,H3: 6.. / I2 = 6  => 14 pairs (_) / H3 = 6  =>  0 pairs (X)
H6,I6: 6.. / H6 = 6  => 14 pairs (_) / I6 = 6  =>  0 pairs (X)
A8,C9: 6.. / A8 = 6  => 18 pairs (_) / C9 = 6  =>  0 pairs (X)
C1,D1: 6.. / C1 = 6  =>  0 pairs (X) / D1 = 6  =>  0 pairs (_)
F2,I2: 6.. / F2 = 6  =>  0 pairs (X) / I2 = 6  => 14 pairs (_)
A8,D8: 6.. / A8 = 6  => 18 pairs (_) / D8 = 6  =>  0 pairs (X)
A5,A8: 6.. / A5 = 6  =>  0 pairs (X) / A8 = 6  => 18 pairs (_)
B3,B4: 6.. / B3 = 6  =>  0 pairs (*) / B4 = 6  =>  0 pairs (X)
H3,H6: 6.. / H3 = 6  =>  0 pairs (X) / H6 = 6  => 14 pairs (_)
I2,I6: 6.. / I2 = 6  => 14 pairs (_) / I6 = 6  =>  0 pairs (X)
A5,C5: 7.. / A5 = 7  => 18 pairs (_) / C5 = 7  =>  0 pairs (X)
A7,C7: 7.. / A7 = 7  =>  0 pairs (X) / C7 = 7  => 18 pairs (_)
A5,A7: 7.. / A5 = 7  => 18 pairs (_) / A7 = 7  =>  0 pairs (X)
C5,C7: 7.. / C5 = 7  =>  0 pairs (X) / C7 = 7  => 18 pairs (_)
C1,B3: 8.. / C1 = 8  =>  0 pairs (*) / B3 = 8  =>  0 pairs (X)
D1,F3: 8.. / D1 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
E4,F4: 8.. / E4 = 8  =>  0 pairs (*) / F4 = 8  =>  0 pairs (X)
I7,I8: 8.. / I7 = 8  =>  0 pairs (X) / I8 = 8  => 22 pairs (_)
C1,D1: 8.. / C1 = 8  =>  0 pairs (*) / D1 = 8  =>  0 pairs (X)
B3,F3: 8.. / B3 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
D8,I8: 8.. / D8 = 8  =>  0 pairs (X) / I8 = 8  => 22 pairs (_)
B3,B7: 8.. / B3 = 8  =>  0 pairs (X) / B7 = 8  =>  0 pairs (_)
E4,E9: 8.. / E4 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
F3,F4: 8.. / F3 = 8  =>  0 pairs (*) / F4 = 8  =>  0 pairs (X)
* DURATION: 0:01:20.934628  START: 15:10:09.246599  END: 15:11:30.181227 2017-05-04
* CP COUNT: (45)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,A8,A9,B3,B4,B7,C1,D1,E5,E9,F2,F4,H3,H6,H8,I2,I6,I9)
* 23..1759447539.81.9.145.3.73.45..179.5.1.94838197342.....94563..43.719...9...374.
* PAIR C1: 6,8 COL C
C9: 6,8,2                                # reduction candidate for 6,8
C9: 2 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
C9: 6,8                                  # 24 pairs
* PAIR B3: 6,8 ROW 3
F3: 6,8,2                                # reduction candidate for 6,8
F3: 2 => CTR
* 23.8175944753968129814523673645281797521694838197342561279456386432719...9...374.
F3: 6,8                                  # 14 pairs
* PAIR D1: 6,8 BLK 2
F3: 6,8,2                                # reduction candidate for 6,8
F3: 2 => CTR
* 23.8175944753968129814523673645281797521694838197342561279456386432719...9...374.
F3: 6,8                                  # 14 pairs
* PAIR D1: 6,8 COL D
D8: 6,8,2                                # reduction candidate for 6,8
D8: 6,8                                  # 24 pairs
D9: 6,8,2                                # reduction candidate for 6,8
D9: 6,8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
D9: 2                                    # 24 pairs
* PAIR F2: 2,6 BLK 2
F3: 2,6,8                                # reduction candidate for 2,6
F3: 2,6 => CTR
* 23.81759447539.81.98145.3.73645281797521694838197342..1279456386432719...9...374.
F3: 8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
* PAIR H3: 2,6 ROW 3
F3: 2,6,8                                # reduction candidate for 2,6
F3: 2,6 => CTR
* 23.81759447539.81.98145.3.73645281797521694838197342..1279456386432719...9...374.
F3: 8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
* PAIR B4: 2,6 BLK 4
C5: 2,6,7                                # reduction candidate for 2,6
C5: 7 => CTR
* 23..1759447539.81.9.145.3.73245..1796571294838197342..782945631543671928196..374.
C5: 2,6                                  # 18 pairs
* PAIR B4: 2,6 ROW 4
E4: 2,6,8                                # reduction candidate for 2,6
E4: 2,6 => CTR
* 23.81759447539.81.98145.3.73645281797521.94838197342.....94563..43.719...9..8374.
E4: 8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
* PAIR A5: 6,7 BLK 4
C5: 6,7,2                                # reduction candidate for 6,7
C5: 6,7 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
C5: 2 => CTR
* 23..1759447539.81.9.145.3.73.45..1797521694838197342..1279456386438719...9...374.
* PAIR F4: 6,8 BLK 5
E4: 6,8,2                                # reduction candidate for 6,8
E4: 6,8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
E4: 2 => CTR
* 23..1759447539.81.9.145.3.73.4528179.521694838197342...279456386438719...9...374.
* PAIR F4: 6,8 COL F
F3: 6,8,2                                # reduction candidate for 6,8
F3: 2 => CTR
* 23.8175944753968129814523673645281797521694838197342561279456386432719...9...374.
F3: 6,8                                  # 14 pairs
* PAIR E5: 2,6 BLK 5
E4: 2,6,8                                # reduction candidate for 2,6
E4: 2,6 => CTR
* 23.81759447539.81.98145.3.73645281797521.94838197342.....94563..43.719...9..8374.
E4: 8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
* PAIR E5: 2,6 ROW 5
C5: 2,6,7                                # reduction candidate for 2,6
C5: 7 => CTR
* 23..1759447539.81.9.145.3.73245..1796571294838197342..782945631543671928196..374.
C5: 2,6                                  # 18 pairs
* PAIR B7: 2,8 BLK 7
C7: 2,8,7                                # reduction candidate for 2,8
C7: 2,8 => CTR
* 23..1759447539.8129.14523673.45..179.571294838197342..7..945631.43.719.819...3745
C7: 7                                    # 18 pairs
C9: 2,8,6                                # reduction candidate for 2,8
C9: 2,8                                  # 18 pairs
* PAIR B7: 2,8 ROW 7
I7: 2,8,1                                # reduction candidate for 2,8
I7: 1 => CTR
* 23..1759447539.8129.145236736452817975.1.94838197342.....945631.43.719.819...3745
I7: 2,8                                  # 18 pairs
* PAIR E9: 6,8 BLK 8
D8: 6,8,2                                # reduction candidate for 6,8
D8: 6,8                                  # 24 pairs
D9: 6,8,2                                # reduction candidate for 6,8
D9: 6,8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
D9: 2                                    # 24 pairs
* PAIR E9: 6,8 ROW 9
C9: 6,8,2                                # reduction candidate for 6,8
C9: 2 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
C9: 6,8                                  # 24 pairs
* PAIR E9: 6,8 COL E
E4: 6,8,2                                # reduction candidate for 6,8
E4: 6,8 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
E4: 2 => CTR
* 23..1759447539.81.9.145.3.73.4528179.521694838197342...279456386438719...9...374.
* PAIR H8: 2,5 BLK 9
I8: 2,5,8                                # reduction candidate for 2,5
I8: 2,5 => CTR
* 23..1759447539.81.9.145.3.73.45..179.5.1.94838197342.....945638.438719...98263741
I8: 8                                    # 22 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-362-base-pr-000.dot
* REASONING
* PRF # C9: 2 => SOL
* DIS # F3: 2 => CTR => F3: 6,8
* DIS # F3: 2 => CTR => F3: 6,8
* PRF # D9: 6,8 => SOL
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* PRF # C5: 6,7 => SOL
* DIS # C5: 2 => CTR => C5: 6,7
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* DIS # F3: 2 => CTR => F3: 6,8
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # C7: 2,8 => CTR => C7: 7
* DIS # I7: 1 => CTR => I7: 2,8
* PRF # D9: 6,8 => SOL
* PRF # C9: 2 => SOL
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* DIS # I8: 2,5 => CTR => I8: 8
* CNT  26 HDP CHAINS /  41 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,A8,A9,B3,B4,B7,C1,D1,E5,E9,F2,F4,H3,H6,H8,I2,I6,I9)
* 23..1759447539.81.9.145.3.73.45..179.5.1.94838197342.....94563..43.719...9...374.
* PAIR C1: 6,8 COL C
C9: 6,8,2                                # reduction candidate for 6,8
C9: 2 => SOLVED
* 238617594475392816961458327324586179756129483819734265187945632643271958592863741
* DURATION: 0:00:02.951832  START: 15:12:14.572491  END: 15:12:17.524323 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-362-base-pr-001.dot
* REASONING
* PRF # C9: 2 => SOL
* STA C9: 2
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 362

solution: 238617594475392816961458327324586179756129483819734265187945632643271958592863741
info: 4947     FNBHWX   S8.f     45357

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

Solution

position: 238617594475392816961458327324586179756129483819734265187945632643271958592863741 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 # C9: 6,8 => UNS
* PRF # C9: 2 => SOL
* INC # F3: 6,8 => UNS
* DIS # F3: 2 => CTR => F3: 6,8
* INC # F3: 6,8 => UNS
* DIS # F3: 2 => CTR => F3: 6,8
* INC # D8: 6,8 => UNS
* PRF # D9: 6,8 => SOL
* INC # D9: 2 => UNS
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* DIS # F3: 2,6 => CTR => F3: 8
* PRF # F3: 8 => SOL
* INC # C5: 2,6 => UNS
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* PRF # C5: 6,7 => SOL
* DIS # C5: 2 => CTR => C5: 6,7
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* INC # F3: 6,8 => UNS
* DIS # F3: 2 => CTR => F3: 6,8
* DIS # E4: 2,6 => CTR => E4: 8
* PRF # E4: 8 => SOL
* INC # C5: 2,6 => UNS
* DIS # C5: 7 => CTR => C5: 2,6
* DIS # C7: 2,8 => CTR => C7: 7
* INC # C7: 7 => UNS
* INC # C9: 2,8 => UNS
* INC # I7: 2,8 => UNS
* DIS # I7: 1 => CTR => I7: 2,8
* INC # D8: 6,8 => UNS
* PRF # D9: 6,8 => SOL
* INC # D9: 2 => UNS
* INC # C9: 6,8 => UNS
* PRF # C9: 2 => SOL
* PRF # E4: 6,8 => SOL
* DIS # E4: 2 => CTR => E4: 6,8
* DIS # I8: 2,5 => CTR => I8: 8
* INC # I8: 8 => UNS
* CNT  41 HDP CHAINS /  41 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C9: 6,8 => UNS
* PRF # C9: 2 => SOL
* STA C9: 2
* CNT   2 HDP CHAINS /   2 HYP OPENED