Analysis of xx-top500-374-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6.....17....3....21............176...2.....3...........3.2....5...46..........8.. initial

Autosolve

position: 6.3.2.17..7.3.1.621.27.63..3...1762..2.6...3..6..32...4362..715.1.4652932..173846 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # G6: 5,9 => SOL
* PRF # A5: 5,9 => SOL
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* DIS # E5: 5,9 => CTR => E5: 4,8
* PRF # G2: 4 => SOL
* DIS # C6: 5,8 => CTR => C6: 1,4,7,9
* PRF # C6: 4,5,8,9 => SOL
* PRF # A6: 7,8 => SOL
* DIS # B3: 5,9 => CTR => B3: 4,8
* DIS # B4: 5,9 => CTR => B4: 4,8
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* DIS # C6: 5,9 => CTR => C6: 1,4,7,8
* PRF # E3: 8,9 => SOL
* DIS # E5: 8,9 => CTR => E5: 4,5
* CNT  14 HDP CHAINS /  43 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 # G6: 5,9 => SOL
* STA G6: 5,9
* CNT   1 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

6.....17....3....21............176...2.....3...........3.2....5...46..........8.. initial
6.3.2.17..7.3.1.621.27.63..3...1762..2.6...3..6..32...4362..715.1.4652932..173846 autosolve
653824179978351462142796358389517624521648937764932581436289715817465293295173846 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
H3: 5,8
G5: 5,9
I5: 1,7
H6: 5,8
I6: 1,7
A8: 7,8
C8: 7,8
B9: 5,9
C9: 5,9
E7: 8,9
F7: 8,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C5,C6: 1.. / C5 = 1  =>  9 pairs (_) / C6 = 1  => 11 pairs (_)
I5,I6: 1.. / I5 = 1  => 11 pairs (_) / I6 = 1  =>  9 pairs (_)
C5,I5: 1.. / C5 = 1  =>  9 pairs (_) / I5 = 1  => 11 pairs (_)
C6,I6: 1.. / C6 = 1  => 11 pairs (_) / I6 = 1  =>  9 pairs (_)
E5,F5: 4.. / E5 = 4  => 19 pairs (_) / F5 = 4  => 12 pairs (_)
I4,G6: 4.. / I4 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
C6,G6: 4.. / C6 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
F1,F5: 4.. / F1 = 4  => 19 pairs (_) / F5 = 4  => 12 pairs (_)
G2,G6: 4.. / G2 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
G2,H3: 5.. / G2 = 5  =>  0 pairs (X) / H3 = 5  => 12 pairs (_)
B9,C9: 5.. / B9 = 5  =>  0 pairs (X) / C9 = 5  => 11 pairs (_)
B1,D1: 5.. / B1 = 5  => 16 pairs (_) / D1 = 5  =>  0 pairs (X)
H3,H6: 5.. / H3 = 5  => 12 pairs (_) / H6 = 5  =>  0 pairs (X)
I5,I6: 7.. / I5 = 7  =>  9 pairs (_) / I6 = 7  => 11 pairs (_)
A8,C8: 7.. / A8 = 7  => 13 pairs (_) / C8 = 7  => 10 pairs (_)
I4,H6: 8.. / I4 = 8  =>  0 pairs (X) / H6 = 8  => 12 pairs (_)
A8,C8: 8.. / A8 = 8  => 10 pairs (_) / C8 = 8  => 13 pairs (_)
E7,F7: 8.. / E7 = 8  =>  0 pairs (*) / F7 = 8  =>  0 pairs (X)
H3,H6: 8.. / H3 = 8  =>  0 pairs (X) / H6 = 8  => 12 pairs (_)
B9,C9: 9.. / B9 = 9  => 11 pairs (_) / C9 = 9  =>  0 pairs (X)
E7,F7: 9.. / E7 = 9  => 12 pairs (_) / F7 = 9  =>  0 pairs (*)
* DURATION: 0:00:34.591113  START: 15:40:34.802480  END: 15:41:09.393593 2017-05-04
* CP COUNT: (21)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B9,C8,C9,E7,F7,G5,H3,H6,I5,I6)
* 6.3.2.17..7.3.1.621.27.63..3...1762..2.6...3..6..32...4362..715.1.4652932..173846
* PAIR H3: 5,8 ROW 3
B3: 5,8,4,9                              # reduction candidate for 5,8
B3: 5,8                                  # 14 pairs
E3: 5,8,4,9                              # reduction candidate for 5,8
E3: 5,8                                  # 14 pairs
* PAIR G5: 5,9 BLK 6
G6: 5,9,4                                # reduction candidate for 5,9
G6: 5,9 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
G6: 4                                    # 13 pairs
* PAIR G5: 5,9 ROW 5
A5: 5,9,7,8                              # reduction candidate for 5,9
A5: 5,9 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
A5: 7,8                                  # 19 pairs
C5: 5,9,1,7,8                            # reduction candidate for 5,9
C5: 5,9 => CTR
* 6.382.174.783419621427.63..3...1762972.6..531.61.324874362..7158174652932..173846
C5: 1,7,8                                # 11 pairs
E5: 5,9,4,8                              # reduction candidate for 5,9
E5: 5,9 => CTR
* 6.352917.5793814621827463593...17624.2.65493.964832...436298715.1.4652932..173846
E5: 4,8                                  # 17 pairs
* PAIR G5: 5,9 COL G
G2: 5,9,4                                # reduction candidate for 5,9
G2: 4 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
G2: 5,9                                  # 13 pairs
* PAIR I5: 1,7 ROW 5
C5: 1,7,5,8,9                            # reduction candidate for 1,7
C5: 5,8,9                                # 13 pairs
C5: 1,7                                  # 12 pairs
* PAIR H6: 5,8 ROW 6
A6: 5,8,7,9                              # reduction candidate for 5,8
A6: 5,8                                  # 18 pairs
C6: 5,8,1,4,7,9                          # reduction candidate for 5,8
C6: 5,8 => CTR
* 6.382.17..78341.621.275638.3...1762..216...3776.9324.14362..7158174652932..173846
C6: 1,4,7,9                              # 11 pairs
D6: 5,8,9                                # reduction candidate for 5,8
D6: 5,8                                  # 14 pairs
* PAIR I6: 1,7 ROW 6
C6: 1,7,4,5,8,9                          # reduction candidate for 1,7
C6: 4,5,8,9 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
C6: 1,7                                  # 14 pairs
* PAIR A8: 7,8 COL A
A5: 7,8,5,9                              # reduction candidate for 7,8
A5: 7,8                                  # 19 pairs
A6: 7,8,5,9                              # reduction candidate for 7,8
A6: 7,8 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
A6: 5,9                                  # 15 pairs
* PAIR C8: 7,8 COL C
C5: 7,8,1,5,9                            # reduction candidate for 7,8
C5: 7,8                                  # 12 pairs
C6: 7,8,1,4,5,9                          # reduction candidate for 7,8
C6: 7,8                                  # 12 pairs
* PAIR B9: 5,9 COL B
B1: 5,9,4,8                              # reduction candidate for 5,9
B1: 5,9                                  # 14 pairs
B3: 5,9,4,8                              # reduction candidate for 5,9
B3: 5,9 => CTR
* 6.352.17.57.3914621927463583.5917624.2.65493.964832...4362..715.1.465293259173846
B3: 4,8                                  # 12 pairs
B4: 5,9,4,8                              # reduction candidate for 5,9
B4: 5,9 => CTR
* 6435291785793814621827463593..817624.2165493..64.32581436298715.1.4652932..173846
B4: 4,8                                  # 12 pairs
* PAIR C9: 5,9 COL C
C2: 5,9,4,8                              # reduction candidate for 5,9
C2: 5,9                                  # 13 pairs
C4: 5,9,4,8                              # reduction candidate for 5,9
C4: 5,9                                  # 13 pairs
C5: 5,9,1,7,8                            # reduction candidate for 5,9
C5: 5,9 => CTR
* 6.382.174.783419621427.63..3...1762972.6..531.61.324874362..7158174652932..173846
C5: 1,7,8                                # 11 pairs
C6: 5,9,1,4,7,8                          # reduction candidate for 5,9
C6: 5,9 => CTR
* 6.382.1745783419621427.63..3...17629.216..53776..324814362..7158174652932..173846
C6: 1,4,7,8                              # 11 pairs
* PAIR E7: 8,9 COL E
E2: 8,9,4,5                              # reduction candidate for 8,9
E2: 8,9                                  # 14 pairs
E3: 8,9,4,5                              # reduction candidate for 8,9
E3: 8,9 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
E3: 4,5                                  # 12 pairs
E5: 8,9,4,5                              # reduction candidate for 8,9
E5: 8,9 => CTR
* 653.2.174.7.3.156214275638938.51762..2.6.4.3..6..324..4362..715.1.465293295173846
E5: 4,5                                  # 12 pairs
* PAIR F7: 8,9 COL F
F1: 8,9,4                                # reduction candidate for 8,9
F1: 8,9                                  # 12 pairs
F5: 8,9,4                                # reduction candidate for 8,9
F5: 8,9                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-374-base-pr-000.dot
* REASONING
* PRF # G6: 5,9 => SOL
* PRF # A5: 5,9 => SOL
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* DIS # E5: 5,9 => CTR => E5: 4,8
* PRF # G2: 4 => SOL
* DIS # C6: 5,8 => CTR => C6: 1,4,7,9
* PRF # C6: 4,5,8,9 => SOL
* PRF # A6: 7,8 => SOL
* DIS # B3: 5,9 => CTR => B3: 4,8
* DIS # B4: 5,9 => CTR => B4: 4,8
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* DIS # C6: 5,9 => CTR => C6: 1,4,7,8
* PRF # E3: 8,9 => SOL
* DIS # E5: 8,9 => CTR => E5: 4,5
* CNT  14 HDP CHAINS /  43 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B9,C8,C9,E7,F7,G5,H3,H6,I5,I6)
* 6.3.2.17..7.3.1.621.27.63..3...1762..2.6...3..6..32...4362..715.1.4652932..173846
* PAIR H3: 5,8 ROW 3
B3: 5,8,4,9                              # reduction candidate for 5,8
B3: 5,8                                  # 14 pairs
E3: 5,8,4,9                              # reduction candidate for 5,8
E3: 5,8                                  # 14 pairs
* PAIR G5: 5,9 BLK 6
G6: 5,9,4                                # reduction candidate for 5,9
G6: 5,9 => SOLVED
* 653824179978351462142796358389517624521648937764932581436289715817465293295173846
* DURATION: 0:00:03.942483  START: 15:41:52.143227  END: 15:41:56.085710 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-374-base-pr-001.dot
* REASONING
* PRF # G6: 5,9 => SOL
* STA G6: 5,9
* CNT   1 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 374

solution: 653824179978351462142796358389517624521648937764932581436289715817465293295173846
info: 6483     FNBHWY   S8.f     42464

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

Solution

position: 653824179978351462142796358389517624521648937764932581436289715817465293295173846 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 # B3: 5,8 => UNS
* INC # E3: 5,8 => UNS
* PRF # G6: 5,9 => SOL
* INC # G6: 4 => UNS
* PRF # A5: 5,9 => SOL
* INC # A5: 7,8 => UNS
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* INC # C5: 1,7,8 => UNS
* DIS # E5: 5,9 => CTR => E5: 4,8
* INC # E5: 4,8 => UNS
* INC # G2: 5,9 => UNS
* PRF # G2: 4 => SOL
* INC # C5: 1,7 => UNS
* INC # C5: 5,8,9 => UNS
* INC # A6: 5,8 => UNS
* DIS # C6: 5,8 => CTR => C6: 1,4,7,9
* INC # C6: 1,4,7,9 => UNS
* INC # D6: 5,8 => UNS
* INC # C6: 1,7 => UNS
* PRF # C6: 4,5,8,9 => SOL
* INC # A5: 7,8 => UNS
* PRF # A6: 7,8 => SOL
* INC # A6: 5,9 => UNS
* INC # C5: 7,8 => UNS
* INC # C6: 7,8 => UNS
* INC # B1: 5,9 => UNS
* DIS # B3: 5,9 => CTR => B3: 4,8
* INC # B3: 4,8 => UNS
* DIS # B4: 5,9 => CTR => B4: 4,8
* INC # B4: 4,8 => UNS
* INC # C2: 5,9 => UNS
* INC # C4: 5,9 => UNS
* DIS # C5: 5,9 => CTR => C5: 1,7,8
* INC # C5: 1,7,8 => UNS
* DIS # C6: 5,9 => CTR => C6: 1,4,7,8
* INC # C6: 1,4,7,8 => UNS
* INC # E2: 8,9 => UNS
* PRF # E3: 8,9 => SOL
* INC # E3: 4,5 => UNS
* DIS # E5: 8,9 => CTR => E5: 4,5
* INC # E5: 4,5 => UNS
* INC # F1: 8,9 => UNS
* INC # F5: 8,9 => UNS
* CNT  43 HDP CHAINS /  43 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 5,8 => UNS
* INC # E3: 5,8 => UNS
* PRF # G6: 5,9 => SOL
* STA G6: 5,9
* CNT   3 HDP CHAINS /   3 HYP OPENED