Analysis of xx-top95-085-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....6...4..6.3....1..4..5.77.....8.5...8.....6.8....9...2.9....4....32....97..1.. initial

Autosolve

position: ....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F1: 2,8 => CTR => F1: 1,5,9
* DIS # F3: 2,8 => CTR => F3: 9
* DIS # B3: 9 => CTR => B3: 2,8
* DIS # F4: 1,4 => CTR => F4: 2,6,9
* CNT   4 HDP CHAINS /  24 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 # F1: 2,8 => CTR => F1: 1,5,9
* DIS F1: 1,5,9 # F3: 2,8 => CTR => F3: 9
* PRF F1: 1,5,9 + F3: 9 # C5: 5 => SOL
* STA F1: 1,5,9 + F3: 9 + C5: 5
* CNT   3 HDP CHAINS /   8 HYP OPENED

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

Details

Positions

....6...4..6.3....1..4..5.77.....8.5...8.....6.8....9...2.9....4....32....97..1.. initial
....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1.. autosolve
957261384846537921123489567734926815295814736618375492572198643481653279369742158 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
C1: 5,7
E3: 2,8
C4: 1,4
G6: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E9,F9: 2.. / E9 = 2  => 11 pairs (_) / F9 = 2  =>  5 pairs (_)
D4,D6: 3.. / D4 = 3  =>  0 pairs (X) / D6 = 3  =>  5 pairs (_)
C4,C5: 4.. / C4 = 4  =>  5 pairs (_) / C5 = 4  =>  6 pairs (_)
A2,D2: 5.. / A2 = 5  => 11 pairs (_) / D2 = 5  => 12 pairs (_)
D4,F4: 6.. / D4 = 6  =>  0 pairs (X) / F4 = 6  =>  4 pairs (_)
G5,I5: 6.. / G5 = 6  =>  5 pairs (_) / I5 = 6  => 12 pairs (_)
B8,D8: 6.. / B8 = 6  =>  7 pairs (_) / D8 = 6  =>  5 pairs (_)
G5,G7: 6.. / G5 = 6  =>  5 pairs (_) / G7 = 6  => 12 pairs (_)
B1,C1: 7.. / B1 = 7  => 18 pairs (_) / C1 = 7  =>  4 pairs (_)
E5,E6: 7.. / E5 = 7  =>  6 pairs (_) / E6 = 7  =>  5 pairs (_)
E6,G6: 7.. / E6 = 7  =>  5 pairs (_) / G6 = 7  =>  6 pairs (_)
C1,C8: 7.. / C1 = 7  =>  4 pairs (_) / C8 = 7  => 18 pairs (_)
B3,F3: 9.. / B3 = 9  =>  0 pairs (X) / F3 = 9  => 10 pairs (_)
A1,A5: 9.. / A1 = 9  => 10 pairs (_) / A5 = 9  =>  0 pairs (X)
D1,D4: 9.. / D1 = 9  =>  0 pairs (X) / D4 = 9  => 10 pairs (_)
* DURATION: 0:00:15.737785  START: 00:54:56.913844  END: 00:55:12.651629 2017-05-04
* CP COUNT: (15)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,C4,E3,G6)
* ....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1..
* PAIR C1: 5,7 BLK 1
B1: 5,7,2,8,9                            # reduction candidate for 5,7
B1: 5,7                                  # 18 pairs
B1: 2,8,9                                # 10 pairs
* PAIR C1: 5,7 COL C
C8: 5,7,1                                # reduction candidate for 5,7
C8: 5,7                                  #  6 pairs
C8: 1                                    #  5 pairs
* PAIR E3: 2,8 BLK 2
F1: 2,8,1,5,9                            # reduction candidate for 2,8
F1: 2,8 => CTR
* ....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1..
F1: 1,5,9                                #  5 pairs
F3: 2,8,9                                # reduction candidate for 2,8
F3: 2,8 => CTR
* ....6.3.4.46.379..1934..5677.....8.59..8.....6.8....9...2.9....4....32.9..97..1..
F3: 9                                    # 10 pairs
* PAIR E3: 2,8 ROW 3
B3: 2,8,9                                # reduction candidate for 2,8
B3: 9 => CTR
* ....6.3.4.46.379..1934..5677.....8.59..8.....6.8....9...2.9....4....32.9..97..1..
B3: 2,8                                  # 10 pairs
* PAIR E3: 2,8 COL E
E9: 2,8,4,5                              # reduction candidate for 2,8
E9: 2,8                                  # 10 pairs
E9: 4,5                                  #  6 pairs
* PAIR C4: 1,4 BLK 4
C5: 1,4,5                                # reduction candidate for 1,4
C5: 1,4                                  #  6 pairs
C5: 5                                    #  5 pairs
* PAIR C4: 1,4 ROW 4
E4: 1,4,2                                # reduction candidate for 1,4
E4: 1,4                                  #  6 pairs
F4: 1,4,2,6,9                            # reduction candidate for 1,4
F4: 1,4 => CTR
* 9...6.3.4.46.379..1.34..56779.6..835...8.9...6.83...9...2.9....46...32.9..97..1..
F4: 2,6,9                                #  4 pairs
H4: 1,4,2,3                              # reduction candidate for 1,4
H4: 1,4                                  # 11 pairs
* PAIR G6: 4,7 BLK 6
G5: 4,7,6                                # reduction candidate for 4,7
G5: 4,7                                  # 12 pairs
H5: 4,7,1,2,3                            # reduction candidate for 4,7
H5: 4,7                                  #  6 pairs
* PAIR G6: 4,7 ROW 6
E6: 4,7,1,2,5                            # reduction candidate for 4,7
E6: 1,2,5                                #  7 pairs
E6: 4,7                                  #  5 pairs
* PAIR G6: 4,7 COL G
G7: 4,7,6                                # reduction candidate for 4,7
G7: 6                                    # 12 pairs
G7: 4,7                                  #  5 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-085-base-pr-000.dot
* REASONING
* DIS # F1: 2,8 => CTR => F1: 1,5,9
* DIS # F3: 2,8 => CTR => F3: 9
* DIS # B3: 9 => CTR => B3: 2,8
* DIS # F4: 1,4 => CTR => F4: 2,6,9
* CNT   4 HDP CHAINS /  24 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,C4,E3,G6)
* ....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1..
* PAIR C1: 5,7 BLK 1
B1: 5,7,2,8,9                            # reduction candidate for 5,7
B1: 5,7                                  # 18 pairs
B1: 2,8,9                                # 10 pairs
* PAIR C1: 5,7 COL C
C8: 5,7,1                                # reduction candidate for 5,7
C8: 5,7                                  #  6 pairs
C8: 1                                    #  5 pairs
* PAIR E3: 2,8 BLK 2
F1: 2,8,1,5,9                            # reduction candidate for 2,8
F1: 2,8 => CTR
* ....6.3.4.46.379..1.34..5677.....8.5...8.....6.8....9...2.9....4....32.9..97..1..
F3: 2,8,9                                # reduction candidate for 2,8
F3: 2,8 => CTR
* ....6.3.4.46.379..1934..5677.....8.59..8.....6.8....9...2.9....4....32.9..97..1..
* PAIR C4: 1,4 BLK 4
C5: 1,4,5                                # reduction candidate for 1,4
C5: 5 => SOLVED
* 957261384846537921123489567734926815295814736618375492572198643481653279369742158
* DURATION: 0:00:06.892750  START: 00:55:27.049553  END: 00:55:33.942303 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-085-base-pr-001.dot
* REASONING
* DIS # F1: 2,8 => CTR => F1: 1,5,9
* DIS F1: 1,5,9 # F3: 2,8 => CTR => F3: 9
* PRF F1: 1,5,9 + F3: 9 # C5: 5 => SOL
* STA F1: 1,5,9 + F3: 9 + C5: 5
* CNT   3 HDP CHAINS /   8 HYP OPENED

Header Info

Top 95 Sudokus 085
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 957261384846537921123489567734926815295814736618375492572198643481653279369742158 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 # B1: 5,7 => UNS
* INC # B1: 2,8,9 => UNS
* INC # C8: 5,7 => UNS
* INC # C8: 1 => UNS
* DIS # F1: 2,8 => CTR => F1: 1,5,9
* INC # F1: 1,5,9 => UNS
* DIS # F3: 2,8 => CTR => F3: 9
* INC # F3: 9 => UNS
* INC # B3: 2,8 => UNS
* DIS # B3: 9 => CTR => B3: 2,8
* INC # E9: 2,8 => UNS
* INC # E9: 4,5 => UNS
* INC # C5: 1,4 => UNS
* INC # C5: 5 => UNS
* INC # E4: 1,4 => UNS
* DIS # F4: 1,4 => CTR => F4: 2,6,9
* INC # F4: 2,6,9 => UNS
* INC # H4: 1,4 => UNS
* INC # G5: 4,7 => UNS
* INC # H5: 4,7 => UNS
* INC # E6: 4,7 => UNS
* INC # E6: 1,2,5 => UNS
* INC # G7: 4,7 => UNS
* INC # G7: 6 => UNS
* CNT  24 HDP CHAINS /  24 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B1: 5,7 => UNS
* INC # B1: 2,8,9 => UNS
* INC # C8: 5,7 => UNS
* INC # C8: 1 => UNS
* DIS # F1: 2,8 => CTR => F1: 1,5,9
* DIS F1: 1,5,9 # F3: 2,8 => CTR => F3: 9
* INC F1: 1,5,9 + F3: 9 # C5: 1,4 => UNS
* PRF F1: 1,5,9 + F3: 9 # C5: 5 => SOL
* STA F1: 1,5,9 + F3: 9 + C5: 5
* CNT   8 HDP CHAINS /   8 HYP OPENED