Analysis of xx-top500-024-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 7..5....83......6.....2....67.3........4..2........1...42.1...........73......... initial

Autosolve

position: 7165349283251..7644..6273516713.2.4..534.12..2.4...13..427136..16.2...73.37....12 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # F9: 8,9 => SOL
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* PRF # F9: 8,9 => SOL
* PRF # A9: 5,8 => SOL
* DIS # A9: 9 => CTR => A9: 5,8
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* PRF # F8: 5 => SOL
* PRF # G8: 8 => SOL
* PRF # F9: 8,9 => SOL
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* CNT  13 HDP CHAINS /  30 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 # F9: 8,9 => SOL
* STA F9: 8,9
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

7..5....83......6.....2....67.3........4..2........1...42.1...........73......... initial
7165349283251..7644..6273516713.2.4..534.12..2.4...13..427136..16.2...73.37....12 autosolve
716534928325198764498627351671382549953471286284956137842713695169245873537869412 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (21)
B3: 8,9
C3: 8,9
E2: 8,9
F2: 8,9
A5: 8,9
B6: 8,9
E4: 8,9
E5: 6,7
D6: 8,9
F6: 5,6
G4: 5,8
I4: 5,9
H5: 8,9
I5: 6,7
I6: 6,7
A7: 5,8
C8: 8,9
E8: 4,5
D9: 8,9
H7: 8,9
I7: 5,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E8,E9: 4.. / E8 = 4  => 22 pairs (_) / E9 = 4  => 22 pairs (_)
G8,G9: 4.. / G8 = 4  => 22 pairs (_) / G9 = 4  => 22 pairs (_)
E8,G8: 4.. / E8 = 4  => 22 pairs (_) / G8 = 4  => 22 pairs (_)
E9,G9: 4.. / E9 = 4  => 22 pairs (_) / G9 = 4  => 22 pairs (_)
E6,F6: 5.. / E6 = 5  => 17 pairs (_) / F6 = 5  => 24 pairs (_)
G4,I4: 5.. / G4 = 5  =>  0 pairs (*) / I4 = 5  =>  0 pairs (X)
A7,A9: 5.. / A7 = 5  =>  0 pairs (X) / A9 = 5  =>  0 pairs (_)
A7,I7: 5.. / A7 = 5  =>  0 pairs (X) / I7 = 5  =>  0 pairs (_)
I4,I7: 5.. / I4 = 5  =>  0 pairs (X) / I7 = 5  =>  0 pairs (_)
I5,I6: 6.. / I5 = 6  => 19 pairs (_) / I6 = 6  => 20 pairs (_)
E9,F9: 6.. / E9 = 6  => 17 pairs (_) / F9 = 6  => 24 pairs (_)
E5,I5: 6.. / E5 = 6  => 20 pairs (_) / I5 = 6  => 19 pairs (_)
F6,F9: 6.. / F6 = 6  => 17 pairs (_) / F9 = 6  => 24 pairs (_)
E5,E6: 7.. / E5 = 7  => 19 pairs (_) / E6 = 7  => 20 pairs (_)
I5,I6: 7.. / I5 = 7  => 20 pairs (_) / I6 = 7  => 19 pairs (_)
E5,I5: 7.. / E5 = 7  => 19 pairs (_) / I5 = 7  => 20 pairs (_)
E6,I6: 7.. / E6 = 7  => 20 pairs (_) / I6 = 7  => 19 pairs (_)
B3,C3: 8.. / B3 = 8  =>  0 pairs (X) / C3 = 8  =>  0 pairs (_)
E2,F2: 8.. / E2 = 8  =>  0 pairs (X) / F2 = 8  =>  0 pairs (_)
A5,B6: 8.. / A5 = 8  =>  0 pairs (X) / B6 = 8  =>  0 pairs (_)
E4,D6: 8.. / E4 = 8  =>  0 pairs (*) / D6 = 8  =>  0 pairs (X)
G4,H5: 8.. / G4 = 8  =>  0 pairs (X) / H5 = 8  =>  0 pairs (_)
E4,G4: 8.. / E4 = 8  =>  0 pairs (*) / G4 = 8  =>  0 pairs (X)
A5,H5: 8.. / A5 = 8  =>  0 pairs (X) / H5 = 8  =>  0 pairs (_)
B6,D6: 8.. / B6 = 8  =>  0 pairs (*) / D6 = 8  =>  0 pairs (X)
A7,H7: 8.. / A7 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
B3,B6: 8.. / B3 = 8  =>  0 pairs (X) / B6 = 8  =>  0 pairs (_)
C3,C8: 8.. / C3 = 8  =>  0 pairs (*) / C8 = 8  =>  0 pairs (X)
D6,D9: 8.. / D6 = 8  =>  0 pairs (X) / D9 = 8  =>  0 pairs (_)
E2,E4: 8.. / E2 = 8  =>  0 pairs (X) / E4 = 8  =>  0 pairs (_)
H5,H7: 8.. / H5 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
B3,C3: 9.. / B3 = 9  =>  0 pairs (*) / C3 = 9  =>  0 pairs (X)
E2,F2: 9.. / E2 = 9  =>  0 pairs (*) / F2 = 9  =>  0 pairs (X)
A5,B6: 9.. / A5 = 9  =>  0 pairs (*) / B6 = 9  =>  0 pairs (X)
E4,D6: 9.. / E4 = 9  =>  0 pairs (X) / D6 = 9  =>  0 pairs (_)
I4,H5: 9.. / I4 = 9  =>  0 pairs (*) / H5 = 9  =>  0 pairs (X)
C8,A9: 9.. / C8 = 9  =>  0 pairs (*) / A9 = 9  =>  0 pairs (X)
H7,I7: 9.. / H7 = 9  =>  0 pairs (*) / I7 = 9  =>  0 pairs (X)
E4,I4: 9.. / E4 = 9  =>  0 pairs (X) / I4 = 9  =>  0 pairs (_)
A5,H5: 9.. / A5 = 9  =>  0 pairs (*) / H5 = 9  =>  0 pairs (X)
B6,D6: 9.. / B6 = 9  =>  0 pairs (X) / D6 = 9  =>  0 pairs (_)
C8,F8: 9.. / C8 = 9  =>  0 pairs (*) / F8 = 9  =>  0 pairs (X)
A5,A9: 9.. / A5 = 9  =>  0 pairs (*) / A9 = 9  =>  0 pairs (X)
B3,B6: 9.. / B3 = 9  =>  0 pairs (*) / B6 = 9  =>  0 pairs (X)
C3,C8: 9.. / C3 = 9  =>  0 pairs (X) / C8 = 9  =>  0 pairs (_)
D6,D9: 9.. / D6 = 9  =>  0 pairs (*) / D9 = 9  =>  0 pairs (X)
E2,E4: 9.. / E2 = 9  =>  0 pairs (*) / E4 = 9  =>  0 pairs (X)
H5,H7: 9.. / H5 = 9  =>  0 pairs (X) / H7 = 9  =>  0 pairs (_)
I4,I7: 9.. / I4 = 9  =>  0 pairs (*) / I7 = 9  =>  0 pairs (X)
* DURATION: 0:01:50.502692  START: 03:24:24.304535  END: 03:26:14.807227 2017-05-04
* CP COUNT: (49)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,B3,B6,C3,C8,D6,D9,E2,E4,E5,E8,F2,F6,G4,H5,H7,I4,I5,I6,I7)
* 7165349283251..7644..6273516713.2.4..534.12..2.4...13..427136..16.2...73.37....12
* PAIR F2: 8,9 COL F
F8: 8,9,5                                # reduction candidate for 8,9
F8: 8,9                                  # 24 pairs
F9: 8,9,5,6                              # reduction candidate for 8,9
F9: 8,9 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
F9: 5,6                                  # 24 pairs
* PAIR A5: 8,9 COL A
A9: 8,9,5                                # reduction candidate for 8,9
A9: 8,9 => CTR
* 7165349283251..7644..6273516713928458534.129.2948..13.5427136891682.9.73.37....12
A9: 5 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
* PAIR E5: 6,7 BLK 5
E6: 6,7,5                                # reduction candidate for 6,7
E6: 6,7                                  # 24 pairs
E6: 5                                    # 17 pairs
* PAIR F6: 5,6 BLK 5
E6: 5,6,7                                # reduction candidate for 5,6
E6: 7                                    # 20 pairs
E6: 5,6                                  # 19 pairs
* PAIR F6: 5,6 COL F
F9: 5,6,8,9                              # reduction candidate for 5,6
F9: 8,9 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
F9: 5,6                                  # 24 pairs
* PAIR G4: 5,8 COL G
G8: 5,8,4                                # reduction candidate for 5,8
G8: 5,8                                  # 22 pairs
G9: 5,8,4                                # reduction candidate for 5,8
G9: 5,8                                  # 22 pairs
* PAIR I6: 6,7 ROW 6
E6: 6,7,5                                # reduction candidate for 6,7
E6: 6,7                                  # 24 pairs
E6: 5                                    # 17 pairs
* PAIR A7: 5,8 BLK 7
A9: 5,8,9                                # reduction candidate for 5,8
A9: 5,8 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
A9: 9 => CTR
* 7165349283251..7644..6273516713.2.4..534.12..2.4...13.5427136891682.9.739378...12
* PAIR C8: 8,9 BLK 7
A9: 8,9,5                                # reduction candidate for 8,9
A9: 8,9 => CTR
* 7165349283251..7644..6273516713928458534.129.2948..13.5427136891682.9.73.37....12
A9: 5 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
* PAIR C8: 8,9 ROW 8
F8: 8,9,5                                # reduction candidate for 8,9
F8: 5 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
F8: 8,9                                  # 24 pairs
* PAIR E8: 4,5 BLK 8
E9: 4,5,6                                # reduction candidate for 4,5
E9: 4,5                                  # 24 pairs
E9: 6                                    # 17 pairs
* PAIR E8: 4,5 ROW 8
G8: 4,5,8                                # reduction candidate for 4,5
G8: 8 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
G8: 4,5                                  # 24 pairs
* PAIR D9: 8,9 BLK 8
F8: 8,9,5                                # reduction candidate for 8,9
F8: 8,9                                  # 24 pairs
F9: 8,9,5,6                              # reduction candidate for 8,9
F9: 8,9 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
F9: 5,6                                  # 24 pairs
* PAIR D9: 8,9 ROW 9
A9: 8,9,5                                # reduction candidate for 8,9
A9: 8,9 => CTR
* 7165349283251..7644..6273516713928458534.129.2948..13.5427136891682.9.73.37....12
A9: 5 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-024-base-pr-000.dot
* REASONING
* PRF # F9: 8,9 => SOL
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* PRF # F9: 8,9 => SOL
* PRF # A9: 5,8 => SOL
* DIS # A9: 9 => CTR => A9: 5,8
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* PRF # F8: 5 => SOL
* PRF # G8: 8 => SOL
* PRF # F9: 8,9 => SOL
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* CNT  13 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,B3,B6,C3,C8,D6,D9,E2,E4,E5,E8,F2,F6,G4,H5,H7,I4,I5,I6,I7)
* 7165349283251..7644..6273516713.2.4..534.12..2.4...13..427136..16.2...73.37....12
* PAIR F2: 8,9 COL F
F8: 8,9,5                                # reduction candidate for 8,9
F8: 8,9                                  # 24 pairs
F9: 8,9,5,6                              # reduction candidate for 8,9
F9: 8,9 => SOLVED
* 716534928325198764498627351671382549953471286284956137842713695169245873537869412
* DURATION: 0:00:03.758607  START: 03:26:58.108536  END: 03:27:01.867143 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-024-base-pr-001.dot
* REASONING
* PRF # F9: 8,9 => SOL
* STA F9: 8,9
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 024

solution: 716534928325198764498627351671382549953471286284956137842713695169245873537869412
info: 1321     FNBTHWX  S8.f     37008

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

Solution

position: 716534928325198764498627351671382549953471286284956137842713695169245873537869412 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 # F8: 8,9 => UNS
* PRF # F9: 8,9 => SOL
* INC # F9: 5,6 => UNS
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* INC # E6: 6,7 => UNS
* INC # E6: 5 => UNS
* INC # E6: 5,6 => UNS
* INC # E6: 7 => UNS
* INC # F9: 5,6 => UNS
* PRF # F9: 8,9 => SOL
* INC # G8: 5,8 => UNS
* INC # G9: 5,8 => UNS
* INC # E6: 6,7 => UNS
* INC # E6: 5 => UNS
* PRF # A9: 5,8 => SOL
* DIS # A9: 9 => CTR => A9: 5,8
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* INC # F8: 8,9 => UNS
* PRF # F8: 5 => SOL
* INC # E9: 4,5 => UNS
* INC # E9: 6 => UNS
* INC # G8: 4,5 => UNS
* PRF # G8: 8 => SOL
* INC # F8: 8,9 => UNS
* PRF # F9: 8,9 => SOL
* INC # F9: 5,6 => UNS
* DIS # A9: 8,9 => CTR => A9: 5
* PRF # A9: 5 => SOL
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # F8: 8,9 => UNS
* PRF # F9: 8,9 => SOL
* STA F9: 8,9
* CNT   2 HDP CHAINS /   2 HYP OPENED