Analysis of xx-top500-159-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6.7.....5...8..4..1........2......6..1.3........4.....54..7........6..1.......3.. initial

Autosolve

position: 637.4.1859..831476184657..32.371.86441.3..75.87.4...3154.1736.83.8.645177615..34. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # F9: 2,9 => SOL
* DIS # F5: 6,9 => CTR => F5: 2,8
* PRF # F5: 2,8 => SOL
* PRF # E5: 2,9 => SOL
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # E9: 8 => SOL
* PRF # E5: 2,9 => SOL
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # F9: 2,9 => SOL
* PRF # F9: 2,9 => SOL
* CNT  11 HDP CHAINS /  22 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 # F5: 2,9 => CTR => F5: 6,8
* PRF F5: 6,8 # F9: 2,9 => SOL
* STA F5: 6,8 + F9: 2,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

6.7.....5...8..4..1........2......6..1.3........4.....54..7........6..1.......3.. initial
637.4.1859..831476184657..32.371.86441.3..75.87.4...3154.1736.83.8.645177615..34. autosolve
637249185952831476184657293293715864416398752875426931549173628328964517761582349 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
B2: 2,5
C2: 2,5
D1: 2,9
F1: 2,9
G3: 2,9
H3: 2,9
B4: 5,9
C5: 6,9
C6: 5,6
F4: 5,9
E6: 2,9
F6: 5,6
I5: 2,9
G6: 2,9
C7: 2,9
B8: 2,9
D8: 2,9
H7: 2,9
I9: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,C2: 2.. / B2 = 2  =>  0 pairs (X) / C2 = 2  =>  0 pairs (_)
D1,F1: 2.. / D1 = 2  =>  0 pairs (*) / F1 = 2  =>  0 pairs (X)
G3,H3: 2.. / G3 = 2  =>  0 pairs (*) / H3 = 2  =>  0 pairs (X)
I5,G6: 2.. / I5 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
C7,B8: 2.. / C7 = 2  =>  0 pairs (X) / B8 = 2  =>  0 pairs (_)
H7,I9: 2.. / H7 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
E6,G6: 2.. / E6 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
C7,H7: 2.. / C7 = 2  =>  0 pairs (X) / H7 = 2  =>  0 pairs (_)
B8,D8: 2.. / B8 = 2  =>  0 pairs (*) / D8 = 2  =>  0 pairs (X)
B2,B8: 2.. / B2 = 2  =>  0 pairs (X) / B8 = 2  =>  0 pairs (_)
C2,C7: 2.. / C2 = 2  =>  0 pairs (*) / C7 = 2  =>  0 pairs (X)
D1,D8: 2.. / D1 = 2  =>  0 pairs (*) / D8 = 2  =>  0 pairs (X)
G3,G6: 2.. / G3 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
H3,H7: 2.. / H3 = 2  =>  0 pairs (X) / H7 = 2  =>  0 pairs (_)
I5,I9: 2.. / I5 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
B2,C2: 5.. / B2 = 5  =>  0 pairs (*) / C2 = 5  =>  0 pairs (X)
B4,C6: 5.. / B4 = 5  =>  0 pairs (X) / C6 = 5  =>  0 pairs (_)
F4,F6: 5.. / F4 = 5  =>  0 pairs (*) / F6 = 5  =>  0 pairs (X)
B4,F4: 5.. / B4 = 5  =>  0 pairs (X) / F4 = 5  =>  0 pairs (_)
C6,F6: 5.. / C6 = 5  =>  0 pairs (*) / F6 = 5  =>  0 pairs (X)
B2,B4: 5.. / B2 = 5  =>  0 pairs (*) / B4 = 5  =>  0 pairs (X)
C2,C6: 5.. / C2 = 5  =>  0 pairs (X) / C6 = 5  =>  0 pairs (_)
C5,C6: 6.. / C5 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
F5,F6: 6.. / F5 = 6  =>  0 pairs (X) / F6 = 6  =>  0 pairs (_)
C5,F5: 6.. / C5 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
C6,F6: 6.. / C6 = 6  =>  0 pairs (X) / F6 = 6  =>  0 pairs (_)
E5,F5: 8.. / E5 = 8  => 20 pairs (_) / F5 = 8  =>  0 pairs (*)
E9,F9: 8.. / E9 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
E5,E9: 8.. / E5 = 8  => 20 pairs (_) / E9 = 8  =>  0 pairs (*)
F5,F9: 8.. / F5 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
D1,F1: 9.. / D1 = 9  =>  0 pairs (X) / F1 = 9  =>  0 pairs (_)
G3,H3: 9.. / G3 = 9  =>  0 pairs (X) / H3 = 9  =>  0 pairs (_)
B4,C5: 9.. / B4 = 9  =>  0 pairs (*) / C5 = 9  =>  0 pairs (X)
I5,G6: 9.. / I5 = 9  =>  0 pairs (X) / G6 = 9  =>  0 pairs (_)
C7,B8: 9.. / C7 = 9  =>  0 pairs (*) / B8 = 9  =>  0 pairs (X)
H7,I9: 9.. / H7 = 9  =>  0 pairs (X) / I9 = 9  =>  0 pairs (_)
B4,F4: 9.. / B4 = 9  =>  0 pairs (*) / F4 = 9  =>  0 pairs (X)
E6,G6: 9.. / E6 = 9  =>  0 pairs (X) / G6 = 9  =>  0 pairs (_)
C7,H7: 9.. / C7 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
B8,D8: 9.. / B8 = 9  =>  0 pairs (X) / D8 = 9  =>  0 pairs (_)
B4,B8: 9.. / B4 = 9  =>  0 pairs (*) / B8 = 9  =>  0 pairs (X)
C5,C7: 9.. / C5 = 9  =>  0 pairs (X) / C7 = 9  =>  0 pairs (_)
D1,D8: 9.. / D1 = 9  =>  0 pairs (X) / D8 = 9  =>  0 pairs (_)
G3,G6: 9.. / G3 = 9  =>  0 pairs (X) / G6 = 9  =>  0 pairs (_)
H3,H7: 9.. / H3 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
I5,I9: 9.. / I5 = 9  =>  0 pairs (X) / I9 = 9  =>  0 pairs (_)
* DURATION: 0:01:20.659168  START: 08:10:52.109552  END: 08:12:12.768720 2017-05-04
* CP COUNT: (46)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B4,B8,C2,C5,C6,C7,D1,D8,E6,F1,F4,F6,G3,G6,H3,H7,I5,I9)
* 637.4.1859..831476184657..32.371.86441.3..75.87.4...3154.1736.83.8.645177615..34.
* PAIR F1: 2,9 COL F
F5: 2,9,6,8                              # reduction candidate for 2,9
F5: 2,9 => CTR
* 637.4.1859..831476184657..32.371.86441638.75.8754.6.31549173628328964517761528349
F5: 6,8                                  # 21 pairs
F9: 2,9,8                                # reduction candidate for 2,9
F9: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
F9: 8                                    # 20 pairs
* PAIR C5: 6,9 ROW 5
F5: 6,9,2,8                              # reduction candidate for 6,9
F5: 6,9 => CTR
* 637.4.1859..831476184657..32.371.86441.38.75287.42.93154.1736283289645177615..34.
F5: 2,8 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
* PAIR E6: 2,9 BLK 5
E5: 2,9,8                                # reduction candidate for 2,9
E5: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
E5: 8                                    # 20 pairs
F5: 2,9,6,8                              # reduction candidate for 2,9
F5: 2,9 => CTR
* 637.4.1859..831476184657..32.371.86441638.75.8754.6.31549173628328964517761528349
F5: 6,8                                  # 21 pairs
* PAIR E6: 2,9 COL E
E9: 2,9,8                                # reduction candidate for 2,9
E9: 8 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
E9: 2,9                                  # 20 pairs
* PAIR I5: 2,9 ROW 5
E5: 2,9,8                                # reduction candidate for 2,9
E5: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
E5: 8                                    # 20 pairs
F5: 2,9,6,8                              # reduction candidate for 2,9
F5: 2,9 => CTR
* 637.4.1859..831476184657..32.371.86441638.75.8754.6.31549173628328964517761528349
F5: 6,8                                  # 21 pairs
* PAIR D8: 2,9 BLK 8
E9: 2,9,8                                # reduction candidate for 2,9
E9: 2,9                                  # 20 pairs
F9: 2,9,8                                # reduction candidate for 2,9
F9: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
F9: 8                                    # 20 pairs
* PAIR I9: 2,9 ROW 9
E9: 2,9,8                                # reduction candidate for 2,9
E9: 2,9                                  # 20 pairs
F9: 2,9,8                                # reduction candidate for 2,9
F9: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
F9: 8                                    # 20 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-159-base-pr-000.dot
* REASONING
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # F9: 2,9 => SOL
* DIS # F5: 6,9 => CTR => F5: 2,8
* PRF # F5: 2,8 => SOL
* PRF # E5: 2,9 => SOL
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # E9: 8 => SOL
* PRF # E5: 2,9 => SOL
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF # F9: 2,9 => SOL
* PRF # F9: 2,9 => SOL
* CNT  11 HDP CHAINS /  22 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B4,B8,C2,C5,C6,C7,D1,D8,E6,F1,F4,F6,G3,G6,H3,H7,I5,I9)
* 637.4.1859..831476184657..32.371.86441.3..75.87.4...3154.1736.83.8.645177615..34.
* PAIR F1: 2,9 COL F
F5: 2,9,6,8                              # reduction candidate for 2,9
F5: 2,9 => CTR
* 637.4.1859..831476184657..32.371.86441638.75.8754.6.31549173628328964517761528349
F9: 2,9,8                                # reduction candidate for 2,9
F9: 2,9 => SOLVED
* 637249185952831476184657293293715864416398752875426931549173628328964517761582349
* DURATION: 0:00:03.337136  START: 08:12:38.629479  END: 08:12:41.966615 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-159-base-pr-001.dot
* REASONING
* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF F5: 6,8 # F9: 2,9 => SOL
* STA F5: 6,8 + F9: 2,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 159

solution: 637249185952831476184657293293715864416398752875426931549173628328964517761582349
info: 1819     FNBTWX   S8.f     35542

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

Solution

position: 637249185952831476184657293293715864416398752875426931549173628328964517761582349 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 # F5: 2,9 => CTR => F5: 6,8
* INC # F5: 6,8 => UNS
* PRF # F9: 2,9 => SOL
* INC # F9: 8 => UNS
* DIS # F5: 6,9 => CTR => F5: 2,8
* PRF # F5: 2,8 => SOL
* PRF # E5: 2,9 => SOL
* INC # E5: 8 => UNS
* DIS # F5: 2,9 => CTR => F5: 6,8
* INC # F5: 6,8 => UNS
* INC # E9: 2,9 => UNS
* PRF # E9: 8 => SOL
* PRF # E5: 2,9 => SOL
* INC # E5: 8 => UNS
* DIS # F5: 2,9 => CTR => F5: 6,8
* INC # F5: 6,8 => UNS
* INC # E9: 2,9 => UNS
* PRF # F9: 2,9 => SOL
* INC # F9: 8 => UNS
* INC # E9: 2,9 => UNS
* PRF # F9: 2,9 => SOL
* INC # F9: 8 => UNS
* CNT  22 HDP CHAINS /  22 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # F5: 2,9 => CTR => F5: 6,8
* PRF F5: 6,8 # F9: 2,9 => SOL
* STA F5: 6,8 + F9: 2,9
* CNT   2 HDP CHAINS /   2 HYP OPENED