Analysis of xx-top500-205-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .8....2......43......17....7......3....6..8....1.......6.2..5..3......74......... initial

Autosolve

position: .8....2.....843......172...7..4...3....6..8....1.......6.2..5..3......74......... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # F9: 5,9 => SOL
* CNT   1 HDP CHAINS /  13 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: 5,9 => SOL
* STA F9: 5,9
* CNT   1 HDP CHAINS /  10 HYP OPENED

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

Details

Positions

.8....2......43......17....7......3....6..8....1.......6.2..5..3......74......... initial
.8....2.....843......172...7..4...3....6..8....1.......6.2..5..3......74......... autosolve
483956217172843965956172483798425136235617849641398752867234591329581674514769328 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (10)
A1: 1,4
C1: 3,7
D1: 5,9
H1: 1,4
I1: 3,7
C4: 6,8
A6: 6,8
D6: 3,7
D8: 5,9
D9: 3,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A1,H1: 1.. / A1 = 1  =>  0 pairs (X) / H1 = 1  => 11 pairs (_)
B8,C8: 2.. / B8 = 2  => 13 pairs (_) / C8 = 2  => 10 pairs (_)
H9,I9: 2.. / H9 = 2  => 10 pairs (_) / I9 = 2  => 10 pairs (_)
A2,A5: 2.. / A2 = 2  => 10 pairs (_) / A5 = 2  => 13 pairs (_)
C1,I1: 3.. / C1 = 3  =>  0 pairs (*) / I1 = 3  =>  0 pairs (X)
E7,I7: 3.. / E7 = 3  =>  0 pairs (*) / I7 = 3  =>  0 pairs (X)
D6,D9: 3.. / D6 = 3  =>  0 pairs (*) / D9 = 3  =>  0 pairs (X)
G3,G9: 3.. / G3 = 3  =>  0 pairs (X) / G9 = 3  =>  0 pairs (_)
F7,F9: 4.. / F7 = 4  =>  0 pairs (*) / F9 = 4  =>  0 pairs (X)
A1,H1: 4.. / A1 = 4  => 11 pairs (_) / H1 = 4  =>  0 pairs (X)
G3,G6: 4.. / G3 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
D1,D8: 5.. / D1 = 5  => 11 pairs (_) / D8 = 5  => 10 pairs (_)
E1,F1: 6.. / E1 = 6  => 11 pairs (_) / F1 = 6  => 11 pairs (_)
C4,A6: 6.. / C4 = 6  =>  9 pairs (_) / A6 = 6  =>  8 pairs (_)
C1,I1: 7.. / C1 = 7  =>  0 pairs (X) / I1 = 7  =>  0 pairs (_)
F5,I5: 7.. / F5 = 7  =>  0 pairs (*) / I5 = 7  =>  0 pairs (X)
C7,F7: 7.. / C7 = 7  =>  0 pairs (*) / F7 = 7  =>  0 pairs (X)
B2,B9: 7.. / B2 = 7  =>  0 pairs (*) / B9 = 7  =>  0 pairs (X)
D6,D9: 7.. / D6 = 7  =>  0 pairs (X) / D9 = 7  =>  0 pairs (_)
G2,G6: 7.. / G2 = 7  =>  0 pairs (X) / G6 = 7  =>  0 pairs (_)
H3,I3: 8.. / H3 = 8  => 11 pairs (_) / I3 = 8  => 10 pairs (_)
C4,A6: 8.. / C4 = 8  =>  8 pairs (_) / A6 = 8  =>  9 pairs (_)
D1,D8: 9.. / D1 = 9  => 10 pairs (_) / D8 = 9  => 11 pairs (_)
* DURATION: 0:00:34.244141  START: 09:48:44.945202  END: 09:49:19.189343 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,C1,C4,D1,D6,D8,D9,H1,I1)
* .8....2.....843......172...7..4...3....6..8....1.......6.2..5..3......74.........
* PAIR A1: 1,4 COL A
A7: 1,4,8,9                              # reduction candidate for 1,4
A7: 1,4                                  # 11 pairs
A9: 1,4,5,8,9                            # reduction candidate for 1,4
A9: 1,4                                  # 14 pairs
* PAIR D1: 5,9 BLK 2
E1: 5,9,6                                # reduction candidate for 5,9
E1: 5,9                                  # 11 pairs
F1: 5,9,6                                # reduction candidate for 5,9
F1: 5,9                                  # 11 pairs
* PAIR H1: 1,4 COL H
H5: 1,4,2,5,9                            # reduction candidate for 1,4
H5: 1,4                                  # 12 pairs
H5: 2,5,9                                # 10 pairs
* PAIR D8: 5,9 BLK 8
E8: 5,9,1,6,8                            # reduction candidate for 5,9
E8: 5,9                                  # 14 pairs
F8: 5,9,1,6,8                            # reduction candidate for 5,9
F8: 5,9                                  # 14 pairs
E9: 5,9,1,3,6,8                          # reduction candidate for 5,9
E9: 5,9                                  # 11 pairs
F9: 5,9,1,4,6,7,8                        # reduction candidate for 5,9
F9: 5,9 => SOLVED
* 483956217172843965956172483798425136235617849641398752867234591329581674514769328
F9: 1,4,6,7,8                            # 10 pairs
* PAIR D8: 5,9 ROW 8
B8: 5,9,1,2                              # reduction candidate for 5,9
B8: 5,9                                  # 14 pairs
C8: 5,9,2,8                              # reduction candidate for 5,9
C8: 5,9                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-205-base-pr-000.dot
* REASONING
* PRF # F9: 5,9 => SOL
* CNT   1 HDP CHAINS /  13 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A6,C1,C4,D1,D6,D8,D9,H1,I1)
* .8....2.....843......172...7..4...3....6..8....1.......6.2..5..3......74.........
* PAIR A1: 1,4 COL A
A7: 1,4,8,9                              # reduction candidate for 1,4
A7: 1,4                                  # 11 pairs
A9: 1,4,5,8,9                            # reduction candidate for 1,4
A9: 1,4                                  # 14 pairs
* PAIR D1: 5,9 BLK 2
E1: 5,9,6                                # reduction candidate for 5,9
E1: 5,9                                  # 11 pairs
F1: 5,9,6                                # reduction candidate for 5,9
F1: 5,9                                  # 11 pairs
* PAIR H1: 1,4 COL H
H5: 1,4,2,5,9                            # reduction candidate for 1,4
H5: 1,4                                  # 12 pairs
H5: 2,5,9                                # 10 pairs
* PAIR D8: 5,9 BLK 8
E8: 5,9,1,6,8                            # reduction candidate for 5,9
E8: 5,9                                  # 14 pairs
F8: 5,9,1,6,8                            # reduction candidate for 5,9
F8: 5,9                                  # 14 pairs
E9: 5,9,1,3,6,8                          # reduction candidate for 5,9
E9: 5,9                                  # 11 pairs
F9: 5,9,1,4,6,7,8                        # reduction candidate for 5,9
F9: 5,9 => SOLVED
* 483956217172843965956172483798425136235617849641398752867234591329581674514769328
* DURATION: 0:00:09.209552  START: 09:49:30.009846  END: 09:49:39.219398 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-205-base-pr-001.dot
* REASONING
* PRF # F9: 5,9 => SOL
* STA F9: 5,9
* CNT   1 HDP CHAINS /  10 HYP OPENED

Header Info

Top 500 Minimum 17 205

solution: 483956217172843965956172483798425136235617849641398752867234591329581674514769328
info: 1894     FNBTHWY  S8.f     23368

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

Solution

position: 483956217172843965956172483798425136235617849641398752867234591329581674514769328 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 # A7: 1,4 => UNS
* INC # A9: 1,4 => UNS
* INC # E1: 5,9 => UNS
* INC # F1: 5,9 => UNS
* INC # H5: 1,4 => UNS
* INC # H5: 2,5,9 => UNS
* INC # E8: 5,9 => UNS
* INC # F8: 5,9 => UNS
* INC # E9: 5,9 => UNS
* PRF # F9: 5,9 => SOL
* INC # F9: 1,4,6,7,8 => UNS
* INC # B8: 5,9 => UNS
* INC # C8: 5,9 => UNS
* CNT  13 HDP CHAINS /  13 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A7: 1,4 => UNS
* INC # A9: 1,4 => UNS
* INC # E1: 5,9 => UNS
* INC # F1: 5,9 => UNS
* INC # H5: 1,4 => UNS
* INC # H5: 2,5,9 => UNS
* INC # E8: 5,9 => UNS
* INC # F8: 5,9 => UNS
* INC # E9: 5,9 => UNS
* PRF # F9: 5,9 => SOL
* STA F9: 5,9
* CNT  10 HDP CHAINS /  10 HYP OPENED