Analysis of xx-top500-378-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .4.....315..72...................26..3...1...8..4.......2.6.7.......34........... initial

Autosolve

position: 2476...3151372.6.....3145721.4.3726.7362.1...82.4.63174.216.7.3..1.7342.37..421.6 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B3: 8 => SOL
* DIS # F1: 8,9 => CTR => F1: 5
* DIS # F7: 5 => CTR => F7: 8,9
* DIS # F1: 8,9 => CTR => F1: 5
* PRF # C9: 8 => SOL
* DIS # H5: 8,9 => CTR => H5: 4,5
* PRF # I5: 8,9 => SOL
* PRF # E5: 5 => SOL
* CNT   8 HDP CHAINS /  37 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 # B3: 8 => SOL
* STA B3: 8
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.4.....315..72...................26..3...1...8..4.......2.6.7.......34........... initial
2476...3151372.6.....3145721.4.3726.7362.1...82.4.63174.216.7.3..1.7342.37..421.6 autosolve
247685931513729684689314572194837265736251849825496317452168793961573428378942156 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
A3: 6,9
C3: 8,9
F2: 8,9
G1: 8,9
B4: 5,9
C6: 5,9
E6: 5,9
G5: 8,9
A8: 6,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H2,I2: 4.. / H2 = 4  => 10 pairs (_) / I2 = 4  => 11 pairs (_)
H5,I5: 4.. / H5 = 4  => 11 pairs (_) / I5 = 4  => 10 pairs (_)
H2,H5: 4.. / H2 = 4  => 10 pairs (_) / H5 = 4  => 11 pairs (_)
I2,I5: 4.. / I2 = 4  => 11 pairs (_) / I5 = 4  => 10 pairs (_)
E1,F1: 5.. / E1 = 5  =>  0 pairs (X) / F1 = 5  => 12 pairs (_)
B4,C6: 5.. / B4 = 5  => 16 pairs (_) / C6 = 5  => 19 pairs (_)
C6,E6: 5.. / C6 = 5  => 19 pairs (_) / E6 = 5  => 16 pairs (_)
C6,C9: 5.. / C6 = 5  => 19 pairs (_) / C9 = 5  => 16 pairs (_)
F1,F7: 5.. / F1 = 5  => 12 pairs (_) / F7 = 5  =>  0 pairs (X)
A3,B3: 6.. / A3 = 6  => 13 pairs (_) / B3 = 6  =>  7 pairs (_)
A8,B8: 6.. / A8 = 6  =>  7 pairs (_) / B8 = 6  => 13 pairs (_)
A3,A8: 6.. / A3 = 6  => 13 pairs (_) / A8 = 6  =>  7 pairs (_)
B3,B8: 6.. / B3 = 6  =>  7 pairs (_) / B8 = 6  => 13 pairs (_)
B3,C3: 8.. / B3 = 8  =>  0 pairs (*) / C3 = 8  =>  0 pairs (X)
D4,E5: 8.. / D4 = 8  => 16 pairs (_) / E5 = 8  => 15 pairs (_)
D4,I4: 8.. / D4 = 8  => 16 pairs (_) / I4 = 8  => 15 pairs (_)
C3,C9: 8.. / C3 = 8  => 10 pairs (_) / C9 = 8  =>  0 pairs (*)
E1,E5: 8.. / E1 = 8  => 16 pairs (_) / E5 = 8  => 15 pairs (_)
G1,G5: 8.. / G1 = 8  => 15 pairs (_) / G5 = 8  => 16 pairs (_)
B4,C6: 9.. / B4 = 9  => 19 pairs (_) / C6 = 9  => 16 pairs (_)
C6,E6: 9.. / C6 = 9  => 16 pairs (_) / E6 = 9  => 19 pairs (_)
A3,A8: 9.. / A3 = 9  =>  7 pairs (_) / A8 = 9  => 13 pairs (_)
G1,G5: 9.. / G1 = 9  => 16 pairs (_) / G5 = 9  => 15 pairs (_)
* DURATION: 0:00:48.059379  START: 15:48:25.430044  END: 15:49:13.489423 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B4,C3,C6,E6,F2,G1,G5)
* 2476...3151372.6.....3145721.4.3726.7362.1...82.4.63174.216.7.3..1.7342.37..421.6
* PAIR A3: 6,9 BLK 1
B3: 6,9,8                                # reduction candidate for 6,9
B3: 8 => SOLVED
* 247685931513729684689314572194837265736251849825496317452168793961573428378942156
B3: 6,9                                  # 10 pairs
* PAIR C3: 8,9 BLK 1
B3: 8,9,6                                # reduction candidate for 8,9
B3: 8,9                                  # 13 pairs
B3: 6                                    #  7 pairs
* PAIR C3: 8,9 COL C
C9: 8,9,5                                # reduction candidate for 8,9
C9: 8,9                                  # 19 pairs
C9: 5                                    # 16 pairs
* PAIR F2: 8,9 BLK 2
E1: 8,9,5                                # reduction candidate for 8,9
E1: 8,9                                  # 12 pairs
F1: 8,9,5                                # reduction candidate for 8,9
F1: 8,9 => CTR
* 2476598315137286949683145721.45372687362819..8254963174.21657.3.5187342937.942156
F1: 5                                    # 12 pairs
* PAIR F2: 8,9 ROW 2
H2: 8,9,4                                # reduction candidate for 8,9
H2: 8,9                                  # 11 pairs
I2: 8,9,4                                # reduction candidate for 8,9
I2: 8,9                                  # 10 pairs
* PAIR F2: 8,9 COL F
F7: 8,9,5                                # reduction candidate for 8,9
F7: 5 => CTR
* 2476598315137286949683145721.45372687362819..8254963174.21657.3.5187342937.942156
F7: 8,9                                  # 12 pairs
* PAIR G1: 8,9 BLK 3
H2: 8,9,4                                # reduction candidate for 8,9
H2: 8,9                                  # 11 pairs
I2: 8,9,4                                # reduction candidate for 8,9
I2: 8,9                                  # 10 pairs
* PAIR G1: 8,9 ROW 1
E1: 8,9,5                                # reduction candidate for 8,9
E1: 8,9                                  # 12 pairs
F1: 8,9,5                                # reduction candidate for 8,9
F1: 8,9 => CTR
* 2476598315137286949683145721.45372687362819..8254963174.21657.3.5187342937.942156
F1: 5                                    # 12 pairs
* PAIR B4: 5,9 ROW 4
D4: 5,9,8                                # reduction candidate for 5,9
D4: 5,9                                  # 15 pairs
I4: 5,9,8                                # reduction candidate for 5,9
I4: 5,9                                  # 16 pairs
* PAIR B4: 5,9 COL B
B7: 5,9,8                                # reduction candidate for 5,9
B7: 5,9                                  # 12 pairs
B8: 5,9,6,8                              # reduction candidate for 5,9
B8: 5,9                                  # 16 pairs
* PAIR C6: 5,9 COL C
C9: 5,9,8                                # reduction candidate for 5,9
C9: 8 => SOLVED
* 247685931513729684689314572194837265736251849825496317452168793961573428378942156
C9: 5,9                                  # 10 pairs
* PAIR E6: 5,9 BLK 5
D4: 5,9,8                                # reduction candidate for 5,9
D4: 5,9                                  # 15 pairs
E5: 5,9,8                                # reduction candidate for 5,9
E5: 5,9                                  # 16 pairs
* PAIR E6: 5,9 COL E
E1: 5,9,8                                # reduction candidate for 5,9
E1: 8                                    # 16 pairs
E1: 5,9                                  # 15 pairs
* PAIR G5: 8,9 BLK 6
I4: 8,9,5                                # reduction candidate for 8,9
I4: 8,9                                  # 13 pairs
H5: 8,9,4,5                              # reduction candidate for 8,9
H5: 8,9 => CTR
* 247685931513729648...3145721948372657362518948254963174.2168753..1.7342.37..421.6
H5: 4,5                                  # 10 pairs
I5: 8,9,4,5                              # reduction candidate for 8,9
I5: 8,9 => SOLVED
* 247685931513729684689314572194837265736251849825496317452168793961573428378942156
I5: 4,5                                  # 10 pairs
* PAIR G5: 8,9 ROW 5
E5: 8,9,5                                # reduction candidate for 8,9
E5: 5 => SOLVED
* 247685931513729684689314572194837265736251849825496317452168793961573428378942156
E5: 8,9                                  # 13 pairs
* PAIR A8: 6,9 BLK 7
B8: 6,9,5,8                              # reduction candidate for 6,9
B8: 6,9                                  # 15 pairs
B8: 5,8                                  #  8 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-378-base-pr-000.dot
* REASONING
* PRF # B3: 8 => SOL
* DIS # F1: 8,9 => CTR => F1: 5
* DIS # F7: 5 => CTR => F7: 8,9
* DIS # F1: 8,9 => CTR => F1: 5
* PRF # C9: 8 => SOL
* DIS # H5: 8,9 => CTR => H5: 4,5
* PRF # I5: 8,9 => SOL
* PRF # E5: 5 => SOL
* CNT   8 HDP CHAINS /  37 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B4,C3,C6,E6,F2,G1,G5)
* 2476...3151372.6.....3145721.4.3726.7362.1...82.4.63174.216.7.3..1.7342.37..421.6
* PAIR A3: 6,9 BLK 1
B3: 6,9,8                                # reduction candidate for 6,9
B3: 8 => SOLVED
* 247685931513729684689314572194837265736251849825496317452168793961573428378942156
* DURATION: 0:00:03.135897  START: 15:49:56.409112  END: 15:49:59.545009 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-378-base-pr-001.dot
* REASONING
* PRF # B3: 8 => SOL
* STA B3: 8
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 378

solution: 247685931513729684689314572194837265736251849825496317452168793961573428378942156
info: 18976    FNBTWXYK S8.f     18573

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

Solution

position: 247685931513729684689314572194837265736251849825496317452168793961573428378942156 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: 6,9 => UNS
* PRF # B3: 8 => SOL
* INC # B3: 8,9 => UNS
* INC # B3: 6 => UNS
* INC # C9: 8,9 => UNS
* INC # C9: 5 => UNS
* INC # E1: 8,9 => UNS
* DIS # F1: 8,9 => CTR => F1: 5
* INC # F1: 5 => UNS
* INC # H2: 8,9 => UNS
* INC # I2: 8,9 => UNS
* INC # F7: 8,9 => UNS
* DIS # F7: 5 => CTR => F7: 8,9
* INC # H2: 8,9 => UNS
* INC # I2: 8,9 => UNS
* INC # E1: 8,9 => UNS
* DIS # F1: 8,9 => CTR => F1: 5
* INC # F1: 5 => UNS
* INC # D4: 5,9 => UNS
* INC # I4: 5,9 => UNS
* INC # B7: 5,9 => UNS
* INC # B8: 5,9 => UNS
* INC # C9: 5,9 => UNS
* PRF # C9: 8 => SOL
* INC # D4: 5,9 => UNS
* INC # E5: 5,9 => UNS
* INC # E1: 5,9 => UNS
* INC # E1: 8 => UNS
* INC # I4: 8,9 => UNS
* DIS # H5: 8,9 => CTR => H5: 4,5
* INC # H5: 4,5 => UNS
* PRF # I5: 8,9 => SOL
* INC # I5: 4,5 => UNS
* INC # E5: 8,9 => UNS
* PRF # E5: 5 => SOL
* INC # B8: 6,9 => UNS
* INC # B8: 5,8 => UNS
* CNT  37 HDP CHAINS /  37 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 6,9 => UNS
* PRF # B3: 8 => SOL
* STA B3: 8
* CNT   2 HDP CHAINS /   2 HYP OPENED