Analysis of xx-top95-089-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..5..8..18......9.......78....4.....64....9......53..2.6.........138..5....9.714. initial

Autosolve

position: ..5..8..18.....59.......78....4.....64....9.5....534.2.6.........138..5....9.714. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E1: 6,7 => CTR => E1: 3,4,9
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* DIS # G1: 3 => CTR => G1: 2,6
* CNT   6 HDP CHAINS /  22 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 # E1: 6,7 => CTR => E1: 3,4,9
* PRF E1: 3,4,9 # F8: 2,6 => SOL
* STA E1: 3,4,9 + F8: 2,6
* CNT   2 HDP CHAINS /  13 HYP OPENED

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

Details

Positions

..5..8..18......9.......78....4.....64....9......53..2.6.........138..5....9.714. initial
..5..8..18.....59.......78....4.....64....9.5....534.2.6.........138..5....9.714. autosolve
935748621876231594124695783512469378643872915789153462267514839491386257358927146 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
D1: 6,7
F5: 1,2
E9: 2,6
G8: 2,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G1,H1: 2.. / G1 = 2  =>  0 pairs (X) / H1 = 2  =>  7 pairs (_)
H1,H7: 2.. / H1 = 2  =>  7 pairs (_) / H7 = 2  =>  0 pairs (X)
C5,H5: 3.. / C5 = 3  =>  7 pairs (_) / H5 = 3  =>  7 pairs (_)
I2,I3: 4.. / I2 = 4  =>  5 pairs (_) / I3 = 4  =>  5 pairs (_)
A1,E1: 4.. / A1 = 4  =>  0 pairs (X) / E1 = 4  =>  5 pairs (_)
A8,F8: 4.. / A8 = 4  =>  0 pairs (*) / F8 = 4  =>  0 pairs (X)
D3,F3: 5.. / D3 = 5  =>  5 pairs (_) / F3 = 5  =>  4 pairs (_)
A4,B4: 5.. / A4 = 5  =>  6 pairs (_) / B4 = 5  =>  4 pairs (_)
A9,B9: 5.. / A9 = 5  =>  4 pairs (_) / B9 = 5  =>  6 pairs (_)
D7,F7: 5.. / D7 = 5  =>  4 pairs (_) / F7 = 5  =>  5 pairs (_)
A4,A9: 5.. / A4 = 5  =>  6 pairs (_) / A9 = 5  =>  4 pairs (_)
B4,B9: 5.. / B4 = 5  =>  4 pairs (_) / B9 = 5  =>  6 pairs (_)
D3,D7: 5.. / D3 = 5  =>  5 pairs (_) / D7 = 5  =>  4 pairs (_)
F3,F7: 5.. / F3 = 5  =>  4 pairs (_) / F7 = 5  =>  5 pairs (_)
C2,C3: 6.. / C2 = 6  =>  5 pairs (_) / C3 = 6  =>  5 pairs (_)
F8,E9: 6.. / F8 = 6  =>  0 pairs (*) / E9 = 6  =>  0 pairs (X)
D6,H6: 6.. / D6 = 6  =>  6 pairs (_) / H6 = 6  =>  8 pairs (_)
E9,I9: 6.. / E9 = 6  =>  6 pairs (_) / I9 = 6  =>  0 pairs (*)
D5,D6: 8.. / D5 = 8  =>  4 pairs (_) / D6 = 8  => 15 pairs (_)
G4,I4: 8.. / G4 = 8  =>  5 pairs (_) / I4 = 8  =>  9 pairs (_)
C5,D5: 8.. / C5 = 8  => 15 pairs (_) / D5 = 8  =>  4 pairs (_)
B6,B9: 8.. / B6 = 8  =>  5 pairs (_) / B9 = 8  =>  8 pairs (_)
G4,G7: 8.. / G4 = 8  =>  5 pairs (_) / G7 = 8  =>  9 pairs (_)
E4,F4: 9.. / E4 = 9  =>  5 pairs (_) / F4 = 9  =>  4 pairs (_)
I7,I8: 9.. / I7 = 9  =>  5 pairs (_) / I8 = 9  =>  5 pairs (_)
F3,F4: 9.. / F3 = 9  =>  5 pairs (_) / F4 = 9  =>  4 pairs (_)
* DURATION: 0:00:29.960444  START: 01:02:17.568794  END: 01:02:47.529238 2017-05-04
* CP COUNT: (26)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,E9,F5,G8)
* ..5..8..18.....59.......78....4.....64....9.5....534.2.6.........138..5....9.714.
* PAIR D1: 6,7 BLK 2
E1: 6,7,3,4,9                            # reduction candidate for 6,7
E1: 6,7 => CTR
* 495678..18.....59....5.978....496...64....9.5..9.53462.64..5.....138465....96714.
E1: 3,4,9                                #  4 pairs
D2: 6,7,1,2                              # reduction candidate for 6,7
D2: 6,7                                  # 17 pairs
E2: 6,7,1,2,3,4                          # reduction candidate for 6,7
E2: 6,7                                  #  7 pairs
* PAIR D1: 6,7 COL D
D6: 6,7,1,8                              # reduction candidate for 6,7
D6: 1,8                                  # 16 pairs
D6: 6,7                                  #  6 pairs
* PAIR F5: 1,2 BLK 5
E4: 1,2,6,7,9                            # reduction candidate for 1,2
E4: 1,2                                  #  9 pairs
F4: 1,2,6,9                              # reduction candidate for 1,2
F4: 1,2                                  # 12 pairs
D5: 1,2,7,8                              # reduction candidate for 1,2
D5: 1,2                                  # 16 pairs
E5: 1,2,7                                # reduction candidate for 1,2
E5: 1,2                                  #  9 pairs
* PAIR F5: 1,2 COL F
F2: 1,2,4,6                              # reduction candidate for 1,2
F2: 1,2                                  #  8 pairs
F3: 1,2,4,5,6,9                          # reduction candidate for 1,2
F3: 1,2                                  #  8 pairs
F7: 1,2,4,5                              # reduction candidate for 1,2
F7: 1,2                                  #  7 pairs
* PAIR E9: 2,6 BLK 8
F8: 2,6,4                                # reduction candidate for 2,6
F8: 2,6 => SOLVED
* 935748621876231594124695783512469378643872915789153462267514839491386257358927146
F8: 4 => CTR
* ..57486218.7...594......78....4..8.764.87.9.5.89.534.2468...379..1384256...967148
* PAIR E9: 2,6 COL E
E2: 2,6,1,3,4,7                          # reduction candidate for 2,6
E2: 2,6                                  #  7 pairs
E3: 2,6,1,3,4,9                          # reduction candidate for 2,6
E3: 2,6                                  #  7 pairs
E4: 2,6,1,7,9                            # reduction candidate for 2,6
E4: 2,6                                  #  7 pairs
* PAIR G8: 2,6 ROW 8
F8: 2,6,4                                # reduction candidate for 2,6
F8: 2,6 => SOLVED
* 935748621876231594124695783512469378643872915789153462267514839491386257358927146
F8: 4 => CTR
* ..57486218.7...594......78....4..8.764.87.9.5.89.534.2468...379..1384256...967148
* PAIR G8: 2,6 COL G
G1: 2,6,3                                # reduction candidate for 2,6
G1: 3 => CTR
* ..56483218.....59......978....4968..64...19.5....53462.6...52..4.138265....96714.
G1: 2,6                                  #  7 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-089-base-pr-000.dot
* REASONING
* DIS # E1: 6,7 => CTR => E1: 3,4,9
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* DIS # G1: 3 => CTR => G1: 2,6
* CNT   6 HDP CHAINS /  22 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,E9,F5,G8)
* ..5..8..18.....59.......78....4.....64....9.5....534.2.6.........138..5....9.714.
* PAIR D1: 6,7 BLK 2
E1: 6,7,3,4,9                            # reduction candidate for 6,7
E1: 6,7 => CTR
* 495678..18.....59....5.978....496...64....9.5..9.53462.64..5.....138465....96714.
D2: 6,7,1,2                              # reduction candidate for 6,7
D2: 6,7                                  # 17 pairs
E2: 6,7,1,2,3,4                          # reduction candidate for 6,7
E2: 6,7                                  #  7 pairs
* PAIR D1: 6,7 COL D
D6: 6,7,1,8                              # reduction candidate for 6,7
D6: 1,8                                  # 16 pairs
D6: 6,7                                  #  6 pairs
* PAIR F5: 1,2 BLK 5
E4: 1,2,6,7,9                            # reduction candidate for 1,2
E4: 1,2                                  # 16 pairs
F4: 1,2,6,9                              # reduction candidate for 1,2
F4: 1,2                                  # 20 pairs
D5: 1,2,7,8                              # reduction candidate for 1,2
D5: 1,2                                  # 16 pairs
E5: 1,2,7                                # reduction candidate for 1,2
E5: 1,2                                  #  9 pairs
* PAIR F5: 1,2 COL F
F2: 1,2,4,6                              # reduction candidate for 1,2
F2: 1,2                                  #  8 pairs
F3: 1,2,4,5,6,9                          # reduction candidate for 1,2
F3: 1,2                                  #  8 pairs
F7: 1,2,4,5                              # reduction candidate for 1,2
F7: 1,2                                  #  7 pairs
* PAIR E9: 2,6 BLK 8
F8: 2,6,4                                # reduction candidate for 2,6
F8: 2,6 => SOLVED
* 935748621876231594124695783512469378643872915789153462267514839491386257358927146
* DURATION: 0:00:11.087876  START: 01:03:04.266242  END: 01:03:15.354118 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-089-base-pr-001.dot
* REASONING
* DIS # E1: 6,7 => CTR => E1: 3,4,9
* PRF E1: 3,4,9 # F8: 2,6 => SOL
* STA E1: 3,4,9 + F8: 2,6
* CNT   2 HDP CHAINS /  13 HYP OPENED

Header Info

Top 95 Sudokus 089
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 935748621876231594124695783512469378643872915789153462267514839491386257358927146 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:

* DIS # E1: 6,7 => CTR => E1: 3,4,9
* INC # E1: 3,4,9 => UNS
* INC # D2: 6,7 => UNS
* INC # E2: 6,7 => UNS
* INC # D6: 6,7 => UNS
* INC # D6: 1,8 => UNS
* INC # E4: 1,2 => UNS
* INC # F4: 1,2 => UNS
* INC # D5: 1,2 => UNS
* INC # E5: 1,2 => UNS
* INC # F2: 1,2 => UNS
* INC # F3: 1,2 => UNS
* INC # F7: 1,2 => UNS
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* INC # E2: 2,6 => UNS
* INC # E3: 2,6 => UNS
* INC # E4: 2,6 => UNS
* PRF # F8: 2,6 => SOL
* DIS # F8: 4 => CTR => F8: 2,6
* INC # G1: 2,6 => UNS
* DIS # G1: 3 => CTR => G1: 2,6
* CNT  22 HDP CHAINS /  22 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # E1: 6,7 => CTR => E1: 3,4,9
* INC E1: 3,4,9 # D2: 6,7 => UNS
* INC E1: 3,4,9 # E2: 6,7 => UNS
* INC E1: 3,4,9 # D6: 6,7 => UNS
* INC E1: 3,4,9 # D6: 1,8 => UNS
* INC E1: 3,4,9 # E4: 1,2 => UNS
* INC E1: 3,4,9 # F4: 1,2 => UNS
* INC E1: 3,4,9 # D5: 1,2 => UNS
* INC E1: 3,4,9 # E5: 1,2 => UNS
* INC E1: 3,4,9 # F2: 1,2 => UNS
* INC E1: 3,4,9 # F3: 1,2 => UNS
* INC E1: 3,4,9 # F7: 1,2 => UNS
* PRF E1: 3,4,9 # F8: 2,6 => SOL
* STA E1: 3,4,9 + F8: 2,6
* CNT  13 HDP CHAINS /  13 HYP OPENED