Analysis of xx-top500-319-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..2.9.3..8.5......1.........9..6..4........58........1.7....2..3..5........1..... initial

Autosolve

position: 7.2.9.3..8.5......1.9.......9..6.74........58........1.7....2..3..5........1..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D1: 4,6 => CTR => D1: 8
* PRF # D1: 8 => SOL
* DIS # F1: 4,6 => CTR => F1: 1,5,8
* PRF # I1: 4,6 => SOL
* DIS # I1: 5 => CTR => I1: 4,6
* DIS # F2: 1,4 => CTR => F2: 2,3,6,7
* DIS # G8: 8 => CTR => G8: 1,4
* DIS # A6: 2,5 => CTR => A6: 4,6
* PRF # B6: 2,5 => SOL
* DIS # B6: 8 => CTR => B6: 2,5
* DIS # F4: 2,5 => CTR => F4: 1,3,8
* PRF # F4: 1,3,8 => SOL
* PRF # A9: 2,5 => SOL
* DIS # A9: 4,6,9 => CTR => A9: 2,5
* PRF # F5: 1,2 => SOL
* PRF # B8: 8 => SOL
* PRF # D4: 2,3 => SOL
* DIS # D4: 8 => CTR => D4: 2,3
* DIS # F4: 2,3 => CTR => F4: 1,5,8
* DIS # E6: 2,3 => CTR => E6: 4,5,7,8
* CNT  20 HDP CHAINS /  34 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 # D1: 4,6 => CTR => D1: 8
* PRF D1: 8 => SOL
* STA D1: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

..2.9.3..8.5......1.........9..6..4........58........1.7....2..3..5........1..... initial
7.2.9.3..8.5......1.9.......9..6.74........58........1.7....2..3..5........1..... autosolve
742895316835617429169234587598361742613742958427958631971483265386529174254176893 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
B1: 4,6
G2: 1,4
A4: 2,5
B5: 1,2
I4: 2,3
G5: 6,9
G6: 6,9
H6: 2,3

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F1,H1: 1.. / F1 = 1  =>  0 pairs (X) / H1 = 1  =>  0 pairs (_)
C4,F4: 1.. / C4 = 1  =>  0 pairs (X) / F4 = 1  =>  0 pairs (_)
C7,H7: 1.. / C7 = 1  =>  0 pairs (*) / H7 = 1  =>  0 pairs (X)
B5,B8: 1.. / B5 = 1  =>  0 pairs (*) / B8 = 1  =>  0 pairs (X)
E2,E5: 1.. / E2 = 1  =>  0 pairs (*) / E5 = 1  =>  0 pairs (X)
G2,G8: 1.. / G2 = 1  =>  0 pairs (X) / G8 = 1  =>  0 pairs (_)
I4,H6: 2.. / I4 = 2  =>  0 pairs (*) / H6 = 2  =>  0 pairs (X)
B2,B3: 3.. / B2 = 3  =>  9 pairs (_) / B3 = 3  =>  9 pairs (_)
I4,H6: 3.. / I4 = 3  => 14 pairs (_) / H6 = 3  =>  0 pairs (*)
F1,I1: 5.. / F1 = 5  =>  0 pairs (*) / I1 = 5  =>  0 pairs (X)
A4,F4: 5.. / A4 = 5  =>  0 pairs (*) / F4 = 5  =>  0 pairs (X)
A7,I7: 5.. / A7 = 5  =>  0 pairs (X) / I7 = 5  =>  0 pairs (_)
B6,B9: 5.. / B6 = 5  =>  0 pairs (X) / B9 = 5  =>  0 pairs (_)
E3,E6: 5.. / E3 = 5  =>  0 pairs (X) / E6 = 5  =>  0 pairs (_)
G3,G9: 5.. / G3 = 5  =>  0 pairs (*) / G9 = 5  =>  0 pairs (X)
G5,G6: 6.. / G5 = 6  =>  7 pairs (_) / G6 = 6  =>  6 pairs (_)
C5,C6: 7.. / C5 = 7  =>  9 pairs (_) / C6 = 7  =>  8 pairs (_)
H2,I2: 9.. / H2 = 9  =>  8 pairs (_) / I2 = 9  =>  8 pairs (_)
G5,G6: 9.. / G5 = 9  =>  6 pairs (_) / G6 = 9  =>  7 pairs (_)
A7,A9: 9.. / A7 = 9  =>  0 pairs (*) / A9 = 9  =>  0 pairs (X)
* DURATION: 0:00:30.385900  START: 13:51:50.571172  END: 13:52:20.957072 2017-05-04
* CP COUNT: (20)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B1,B5,G2,G5,G6,H6,I4)
* 7.2.9.3..8.5......1.9.......9..6.74........58........1.7....2..3..5........1.....
* PAIR B1: 4,6 BLK 1
B2: 4,6,3                                # reduction candidate for 4,6
B2: 4,6                                  #  9 pairs
B3: 4,6,3                                # reduction candidate for 4,6
B3: 4,6                                  #  9 pairs
* PAIR B1: 4,6 ROW 1
D1: 4,6,8                                # reduction candidate for 4,6
D1: 4,6 => CTR
* 7.2.9.3.58.5......1.9......29..65743.1.....58.5.....2157....2..3..5.....9..1..5..
D1: 8 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
F1: 4,6,1,5,8                            # reduction candidate for 4,6
F1: 4,6 => CTR
* 7.2.9.3158.5...4..1.9...8...9..6.74........58........1571...2..3..5..1..9..1..5..
F1: 1,5,8                                #  8 pairs
I1: 4,6,5                                # reduction candidate for 4,6
I1: 4,6 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
I1: 5 => CTR
* 7.2.9.3.58.5......1.9......29..65743.1.....58.5.....2157....2..3..5.....9..1..5..
* PAIR G2: 1,4 ROW 2
E2: 1,4,2,3,7                            # reduction candidate for 1,4
E2: 1,4                                  # 10 pairs
F2: 1,4,2,3,6,7                          # reduction candidate for 1,4
F2: 1,4 => CTR
* 7.2.913.58.5..41..1.9......591.6.74..2..1..58........1.7....21.31.5.....2..1.....
F2: 2,3,6,7                              #  8 pairs
* PAIR G2: 1,4 COL G
G8: 1,4,8                                # reduction candidate for 1,4
G8: 8 => CTR
* 7.2.913.58.5...1..1.9...4...91.6.74..2..1..58........157....2..31.5..8.....1.....
G8: 1,4                                  # 11 pairs
* PAIR A4: 2,5 BLK 4
A6: 2,5,4,6                              # reduction candidate for 2,5
A6: 2,5 => CTR
* 7.2.9531.8.5.1.4..1.9...58.593861742.1.....5828..5..31.71...2.532.5..1.4.5.1..8.3
A6: 4,6                                  #  9 pairs
B6: 2,5,8                                # reduction candidate for 2,5
B6: 2,5 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
B6: 8 => CTR
* 7.28953168.5...4..1.9...58.593.6.74........58.8..5...1.71...2.532.5..1...5.1..8..
* PAIR A4: 2,5 ROW 4
F4: 2,5,1,3,8                            # reduction candidate for 2,5
F4: 2,5 => CTR
* 7.2.913858.5...1..1.9...4..59186.743.2.....58.......21.7....21.31.5.....2..1...3.
F4: 1,3,8 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
* PAIR A4: 2,5 COL A
A9: 2,5,4,6,9                            # reduction candidate for 2,5
A9: 2,5 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
A9: 4,6,9 => CTR
* 7.2.953168.5.1.4..1.9...58.593861742.1.....58.8..5..31.71...2.53285..1...5.1..8.3
* PAIR B5: 1,2 ROW 5
E5: 1,2,3,4,7                            # reduction candidate for 1,2
E5: 1,2                                  # 10 pairs
F5: 1,2,3,4,7,9                          # reduction candidate for 1,2
F5: 1,2 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
F5: 3,4,7,9                              #  8 pairs
* PAIR B5: 1,2 COL B
B8: 1,2,8                                # reduction candidate for 1,2
B8: 8 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
B8: 1,2                                  # 11 pairs
* PAIR I4: 2,3 ROW 4
D4: 2,3,8                                # reduction candidate for 2,3
D4: 2,3 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
D4: 8 => CTR
* 7.2.9.3.58.5......1.9......29.865743.1.....58........157....2..3..5.....9..1..5..
F4: 2,3,1,5,8                            # reduction candidate for 2,3
F4: 2,3 => CTR
* 7.2.9.3..8.5......1.9......59186.74..2.....58.8......1.7....21531.5.....25.1.....
F4: 1,5,8                                #  8 pairs
* PAIR H6: 2,3 ROW 6
D6: 2,3,4,7,8,9                          # reduction candidate for 2,3
D6: 2,3                                  # 10 pairs
E6: 2,3,4,5,7,8                          # reduction candidate for 2,3
E6: 2,3 => CTR
* 7.2.9.3.58.5......1.9.5....29..65743.1.....58.5.....2157....2..3..5.....9..1..5..
E6: 4,5,7,8                              #  8 pairs
F6: 2,3,4,5,7,8,9                        # reduction candidate for 2,3
F6: 2,3                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-319-base-pr-000.dot
* REASONING
* DIS # D1: 4,6 => CTR => D1: 8
* PRF # D1: 8 => SOL
* DIS # F1: 4,6 => CTR => F1: 1,5,8
* PRF # I1: 4,6 => SOL
* DIS # I1: 5 => CTR => I1: 4,6
* DIS # F2: 1,4 => CTR => F2: 2,3,6,7
* DIS # G8: 8 => CTR => G8: 1,4
* DIS # A6: 2,5 => CTR => A6: 4,6
* PRF # B6: 2,5 => SOL
* DIS # B6: 8 => CTR => B6: 2,5
* DIS # F4: 2,5 => CTR => F4: 1,3,8
* PRF # F4: 1,3,8 => SOL
* PRF # A9: 2,5 => SOL
* DIS # A9: 4,6,9 => CTR => A9: 2,5
* PRF # F5: 1,2 => SOL
* PRF # B8: 8 => SOL
* PRF # D4: 2,3 => SOL
* DIS # D4: 8 => CTR => D4: 2,3
* DIS # F4: 2,3 => CTR => F4: 1,5,8
* DIS # E6: 2,3 => CTR => E6: 4,5,7,8
* CNT  20 HDP CHAINS /  34 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B1,B5,G2,G5,G6,H6,I4)
* 7.2.9.3..8.5......1.9.......9..6.74........58........1.7....2..3..5........1.....
* PAIR B1: 4,6 BLK 1
B2: 4,6,3                                # reduction candidate for 4,6
B2: 4,6                                  #  9 pairs
B3: 4,6,3                                # reduction candidate for 4,6
B3: 4,6                                  #  9 pairs
* PAIR B1: 4,6 ROW 1
D1: 4,6,8                                # reduction candidate for 4,6
D1: 4,6 => CTR
* 7.2.9.3.58.5......1.9......29..65743.1.....58.5.....2157....2..3..5.....9..1..5..
D1: 8 => SOLVED
* 742895316835617429169234587598361742613742958427958631971483265386529174254176893
* DURATION: 0:00:02.970078  START: 13:52:49.708898  END: 13:52:52.678976 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-319-base-pr-001.dot
* REASONING
* DIS # D1: 4,6 => CTR => D1: 8
* PRF D1: 8 => SOL
* STA D1: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 319

solution: 742895316835617429169234587598361742613742958427958631971483265386529174254176893
info: 2914     FNBTHWY  S8.f     13278

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

Solution

position: 742895316835617429169234587598361742613742958427958631971483265386529174254176893 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 # B2: 4,6 => UNS
* INC # B3: 4,6 => UNS
* DIS # D1: 4,6 => CTR => D1: 8
* PRF # D1: 8 => SOL
* DIS # F1: 4,6 => CTR => F1: 1,5,8
* INC # F1: 1,5,8 => UNS
* PRF # I1: 4,6 => SOL
* DIS # I1: 5 => CTR => I1: 4,6
* INC # E2: 1,4 => UNS
* DIS # F2: 1,4 => CTR => F2: 2,3,6,7
* INC # F2: 2,3,6,7 => UNS
* INC # G8: 1,4 => UNS
* DIS # G8: 8 => CTR => G8: 1,4
* DIS # A6: 2,5 => CTR => A6: 4,6
* INC # A6: 4,6 => UNS
* PRF # B6: 2,5 => SOL
* DIS # B6: 8 => CTR => B6: 2,5
* DIS # F4: 2,5 => CTR => F4: 1,3,8
* PRF # F4: 1,3,8 => SOL
* PRF # A9: 2,5 => SOL
* DIS # A9: 4,6,9 => CTR => A9: 2,5
* INC # E5: 1,2 => UNS
* PRF # F5: 1,2 => SOL
* INC # F5: 3,4,7,9 => UNS
* INC # B8: 1,2 => UNS
* PRF # B8: 8 => SOL
* PRF # D4: 2,3 => SOL
* DIS # D4: 8 => CTR => D4: 2,3
* DIS # F4: 2,3 => CTR => F4: 1,5,8
* INC # F4: 1,5,8 => UNS
* INC # D6: 2,3 => UNS
* DIS # E6: 2,3 => CTR => E6: 4,5,7,8
* INC # E6: 4,5,7,8 => UNS
* INC # F6: 2,3 => UNS
* CNT  34 HDP CHAINS /  34 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B2: 4,6 => UNS
* INC # B3: 4,6 => UNS
* DIS # D1: 4,6 => CTR => D1: 8
* PRF D1: 8 => SOL
* STA D1: 8
* CNT   4 HDP CHAINS /   3 HYP OPENED