Analysis of xx-top500-411-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 71..2...8.......6.4..........65...1..35............4..2.....9.....6.3......1..... initial

Autosolve

position: 719.26..835.....6.46........465...1..352..6...27.6.4..2.1...9365.46.3...6.31.2... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # H9: 4,5 => SOL
* DIS # H9: 7,8 => CTR => H9: 4,5
* DIS # I4: 7,9 => CTR => I4: 2,3
* DIS # I2: 7,9 => CTR => I2: 1,2,4
* DIS # E7: 7,8 => CTR => E7: 4,5
* DIS # F7: 7,8 => CTR => F7: 4,5
* CNT   6 HDP CHAINS /  21 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 # H9: 4,5 => SOL
* STA H9: 4,5
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

71..2...8.......6.4..........65...1..35............4..2.....9.....6.3......1..... initial
719.26..835.....6.46........465...1..352..6...27.6.4..2.1...9365.46.3...6.31.2... autosolve
719426358352918764468735192946587213835241679127369485271854936594673821683192547 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
C2: 2,8
C3: 2,8
D1: 3,4
G1: 3,5
H1: 4,5
A4: 8,9
I5: 7,9
B7: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A5,A6: 1.. / A5 = 1  =>  9 pairs (_) / A6 = 1  => 12 pairs (_)
G8,I8: 1.. / G8 = 1  => 10 pairs (_) / I8 = 1  =>  8 pairs (_)
A6,F6: 1.. / A6 = 1  => 12 pairs (_) / F6 = 1  =>  9 pairs (_)
C2,C3: 2.. / C2 = 2  =>  7 pairs (_) / C3 = 2  =>  8 pairs (_)
G4,I4: 2.. / G4 = 2  => 10 pairs (_) / I4 = 2  =>  9 pairs (_)
H3,H8: 2.. / H3 = 2  => 14 pairs (_) / H8 = 2  => 10 pairs (_)
E4,D6: 3.. / E4 = 3  =>  0 pairs (X) / D6 = 3  =>  0 pairs (_)
D1,G1: 3.. / D1 = 3  =>  0 pairs (X) / G1 = 3  =>  0 pairs (_)
D6,I6: 3.. / D6 = 3  =>  0 pairs (*) / I6 = 3  =>  0 pairs (X)
E3,E4: 3.. / E3 = 3  =>  0 pairs (*) / E4 = 3  =>  0 pairs (X)
H1,I2: 4.. / H1 = 4  =>  0 pairs (X) / I2 = 4  =>  0 pairs (_)
E5,F5: 4.. / E5 = 4  =>  8 pairs (_) / F5 = 4  =>  8 pairs (_)
H9,I9: 4.. / H9 = 4  =>  0 pairs (*) / I9 = 4  =>  0 pairs (X)
D1,H1: 4.. / D1 = 4  =>  0 pairs (*) / H1 = 4  =>  0 pairs (X)
H1,H9: 4.. / H1 = 4  =>  0 pairs (X) / H9 = 4  =>  0 pairs (_)
I2,I9: 4.. / I2 = 4  =>  0 pairs (*) / I9 = 4  =>  0 pairs (X)
E3,F3: 5.. / E3 = 5  =>  0 pairs (X) / F3 = 5  =>  8 pairs (_)
G1,H1: 5.. / G1 = 5  =>  0 pairs (X) / H1 = 5  =>  0 pairs (_)
H6,I6: 5.. / H6 = 5  =>  0 pairs (X) / I6 = 5  =>  0 pairs (_)
E7,F7: 5.. / E7 = 5  =>  8 pairs (_) / F7 = 5  =>  0 pairs (X)
E3,E7: 5.. / E3 = 5  =>  0 pairs (X) / E7 = 5  =>  8 pairs (_)
F3,F7: 5.. / F3 = 5  =>  8 pairs (_) / F7 = 5  =>  0 pairs (X)
G1,G9: 5.. / G1 = 5  =>  0 pairs (X) / G9 = 5  =>  0 pairs (_)
I6,I9: 5.. / I6 = 5  =>  0 pairs (*) / I9 = 5  =>  0 pairs (X)
C2,C3: 8.. / C2 = 8  =>  8 pairs (_) / C3 = 8  =>  7 pairs (_)
B8,B9: 9.. / B8 = 9  => 10 pairs (_) / B9 = 9  => 10 pairs (_)
E8,E9: 9.. / E8 = 9  => 10 pairs (_) / E9 = 9  => 10 pairs (_)
B8,E8: 9.. / B8 = 9  => 10 pairs (_) / E8 = 9  => 10 pairs (_)
B9,E9: 9.. / B9 = 9  => 10 pairs (_) / E9 = 9  => 10 pairs (_)
* DURATION: 0:00:42.468013  START: 16:51:44.939980  END: 16:52:27.407993 2017-05-04
* CP COUNT: (29)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B7,C2,C3,D1,G1,H1,I5)
* 719.26..835.....6.46........465...1..352..6...27.6.4..2.1...9365.46.3...6.31.2...
* PAIR H1: 4,5 COL H
H9: 4,5,7,8                              # reduction candidate for 4,5
H9: 4,5 => SOLVED
* 719426358352918764468735192946587213835241679127369485271854936594673821683192547
H9: 7,8 => CTR
* 719.26.4835.....6.46........465...1..352..6...27.6.45.2.1...9365.46.3...6.31.2...
* PAIR A4: 8,9 BLK 4
A5: 8,9,1                                # reduction candidate for 8,9
A5: 8,9                                  # 12 pairs
A6: 8,9,1                                # reduction candidate for 8,9
A6: 8,9                                  #  9 pairs
* PAIR A4: 8,9 ROW 4
F4: 8,9,7                                # reduction candidate for 8,9
F4: 8,9                                  # 11 pairs
F4: 7                                    #  9 pairs
* PAIR I5: 7,9 BLK 6
I4: 7,9,2,3                              # reduction candidate for 7,9
I4: 7,9 => CTR
* 719.2654835.....6.46....3...4653.21..352..6...27.6.4532.1...9365.46.3...6.31.2..5
I4: 2,3                                  #  9 pairs
H5: 7,9,8                                # reduction candidate for 7,9
H5: 7,9                                  # 13 pairs
* PAIR I5: 7,9 ROW 5
F5: 7,9,1,4,8                            # reduction candidate for 7,9
F5: 7,9                                  # 12 pairs
F5: 1,4,8                                #  8 pairs
* PAIR I5: 7,9 COL I
I2: 7,9,1,2,4                            # reduction candidate for 7,9
I2: 7,9 => CTR
* 71932654835.....6.46........4653..1..352..6...27.6.4..2.1...9365.46.3...6.31.2..4
I2: 1,2,4                                #  8 pairs
I3: 7,9,1,2,3                            # reduction candidate for 7,9
I3: 7,9                                  # 13 pairs
* PAIR B7: 7,8 BLK 7
B8: 7,8,9                                # reduction candidate for 7,8
B8: 7,8                                  # 10 pairs
B9: 7,8,9                                # reduction candidate for 7,8
B9: 7,8                                  # 10 pairs
* PAIR B7: 7,8 ROW 7
D7: 7,8,4                                # reduction candidate for 7,8
D7: 7,8                                  # 11 pairs
E7: 7,8,4,5                              # reduction candidate for 7,8
E7: 7,8 => CTR
* 719.2654835.....6.46..5.3...4653..1..352..6...27.6.4532.14.59365.46.3...6.31.2..5
E7: 4,5                                  #  9 pairs
F7: 7,8,4,5                              # reduction candidate for 7,8
F7: 7,8 => CTR
* 71932654835.....6.46...5....4653..1..352..6...27.6.4.32.145.9365.46.3...6.31.2...
F7: 4,5                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-411-base-pr-000.dot
* REASONING
* PRF # H9: 4,5 => SOL
* DIS # H9: 7,8 => CTR => H9: 4,5
* DIS # I4: 7,9 => CTR => I4: 2,3
* DIS # I2: 7,9 => CTR => I2: 1,2,4
* DIS # E7: 7,8 => CTR => E7: 4,5
* DIS # F7: 7,8 => CTR => F7: 4,5
* CNT   6 HDP CHAINS /  21 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B7,C2,C3,D1,G1,H1,I5)
* 719.26..835.....6.46........465...1..352..6...27.6.4..2.1...9365.46.3...6.31.2...
* PAIR H1: 4,5 COL H
H9: 4,5,7,8                              # reduction candidate for 4,5
H9: 4,5 => SOLVED
* 719426358352918764468735192946587213835241679127369485271854936594673821683192547
* DURATION: 0:00:02.575119  START: 16:52:43.533035  END: 16:52:46.108154 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-411-base-pr-001.dot
* REASONING
* PRF # H9: 4,5 => SOL
* STA H9: 4,5
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 411

solution: 719426358352918764468735192946587213835241679127369485271854936594673821683192547
info: 95022    FNBXYK   S8.f     37504

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

Solution

position: 719426358352918764468735192946587213835241679127369485271854936594673821683192547 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:

* PRF # H9: 4,5 => SOL
* DIS # H9: 7,8 => CTR => H9: 4,5
* INC # A5: 8,9 => UNS
* INC # A6: 8,9 => UNS
* INC # F4: 8,9 => UNS
* INC # F4: 7 => UNS
* DIS # I4: 7,9 => CTR => I4: 2,3
* INC # I4: 2,3 => UNS
* INC # H5: 7,9 => UNS
* INC # F5: 7,9 => UNS
* INC # F5: 1,4,8 => UNS
* DIS # I2: 7,9 => CTR => I2: 1,2,4
* INC # I2: 1,2,4 => UNS
* INC # I3: 7,9 => UNS
* INC # B8: 7,8 => UNS
* INC # B9: 7,8 => UNS
* INC # D7: 7,8 => UNS
* DIS # E7: 7,8 => CTR => E7: 4,5
* INC # E7: 4,5 => UNS
* DIS # F7: 7,8 => CTR => F7: 4,5
* INC # F7: 4,5 => UNS
* CNT  21 HDP CHAINS /  21 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # H9: 4,5 => SOL
* STA H9: 4,5
* CNT   1 HDP CHAINS /   1 HYP OPENED