Analysis of xx-top95-055-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...52.....9...3..4......7...1.....4..8..453..6...1...87.2........8....32.4..8..1. initial

Autosolve

position: ...52.....9...3..4......7...1.....4..8..453.16.4.1...87.2......1.8....32.4..8..17 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E4: 6,7 => CTR => E4: 3,9
* DIS # E8: 6,7 => CTR => E8: 5,9
* PRF # E4: 6,9 => SOL
* DIS # E7: 6,9 => CTR => E7: 3,5
* DIS # E8: 6,9 => CTR => E8: 5,7
* DIS # D5: 2,9 => CTR => D5: 6,7
* DIS # C9: 5,6 => CTR => C9: 3,9
* DIS # G8: 5,6 => CTR => G8: 4,9
* DIS # B3: 5,6 => CTR => B3: 2,3
* DIS # D9: 3 => CTR => D9: 2,6
* DIS # G8: 5,6 => CTR => G8: 4,9
* DIS # C9: 5,6 => CTR => C9: 3,9
* CNT  12 HDP CHAINS /  49 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 # E4: 6,7 => CTR => E4: 3,9
* DIS E4: 3,9 # E8: 6,7 => CTR => E8: 5,9
* DIS E4: 3,9 + E8: 5,9 # E7: 6,9 => CTR => E7: 3,5
* DIS E4: 3,9 + E8: 5,9 + E7: 3,5 # D5: 2,9 => CTR => D5: 6,7
* PRF E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # B7: 5,6 => SOL
* STA E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 + B7: 5,6
* CNT   5 HDP CHAINS /  27 HYP OPENED

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

Details

Positions

...52.....9...3..4......7...1.....4..8..453..6...1...87.2........8....32.4..8..1. initial
...52.....9...3..4......7...1.....4..8..453.16.4.1...87.2......1.8....32.4..8..17 autosolve
476529183895173624321864795517398246289645371634712958752431869168957432943286517 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
E2: 6,7
E3: 6,9
A5: 2,9
C5: 7,9
B8: 5,6
F9: 2,6
G9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G1,G2: 1.. / G1 = 1  =>  7 pairs (_) / G2 = 1  =>  7 pairs (_)
D7,F7: 1.. / D7 = 1  =>  7 pairs (_) / F7 = 1  =>  7 pairs (_)
D9,F9: 2.. / D9 = 2  => 13 pairs (_) / F9 = 2  =>  8 pairs (_)
B3,B6: 2.. / B3 = 2  =>  8 pairs (_) / B6 = 2  =>  0 pairs (X)
I1,I3: 3.. / I1 = 3  =>  9 pairs (_) / I3 = 3  =>  8 pairs (_)
B6,D6: 3.. / B6 = 3  => 13 pairs (_) / D6 = 3  =>  0 pairs (X)
E4,E7: 3.. / E4 = 3  =>  0 pairs (X) / E7 = 3  =>  0 pairs (_)
A1,A3: 4.. / A1 = 4  =>  7 pairs (_) / A3 = 4  =>  8 pairs (_)
G7,G8: 4.. / G7 = 4  => 10 pairs (_) / G8 = 4  =>  9 pairs (_)
A1,F1: 4.. / A1 = 4  =>  7 pairs (_) / F1 = 4  =>  8 pairs (_)
E7,E8: 5.. / E7 = 5  =>  0 pairs (X) / E8 = 5  =>  9 pairs (_)
D5,H5: 6.. / D5 = 6  =>  8 pairs (_) / H5 = 6  => 10 pairs (_)
H5,H6: 7.. / H5 = 7  =>  8 pairs (_) / H6 = 7  =>  8 pairs (_)
B1,B6: 7.. / B1 = 7  =>  7 pairs (_) / B6 = 7  =>  0 pairs (X)
D4,F4: 8.. / D4 = 8  =>  7 pairs (_) / F4 = 8  =>  7 pairs (_)
G7,H7: 8.. / G7 = 8  =>  9 pairs (_) / H7 = 8  => 10 pairs (_)
A9,C9: 9.. / A9 = 9  =>  8 pairs (_) / C9 = 9  =>  9 pairs (_)
* DURATION: 0:00:19.465129  START: 00:00:53.112446  END: 00:01:12.577575 2017-05-04
* CP COUNT: (17)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,B8,C5,E2,E3,F9,G9)
* ...52.....9...3..4......7...1.....4..8..453.16.4.1...87.2......1.8....32.4..8..17
* PAIR E2: 6,7 BLK 2
F1: 6,7,1,4,8,9                          # reduction candidate for 6,7
F1: 6,7                                  #  8 pairs
D2: 6,7,1,8                              # reduction candidate for 6,7
D2: 6,7                                  #  8 pairs
* PAIR E2: 6,7 ROW 2
C2: 6,7,1,5                              # reduction candidate for 6,7
C2: 6,7                                  #  9 pairs
C2: 1,5                                  #  8 pairs
* PAIR E2: 6,7 COL E
E4: 6,7,3,9                              # reduction candidate for 6,7
E4: 6,7 => CTR
* .7.52...3.9..63..4....9.7.5.17....4..896453716.4.1..58752.3....168.5..32943286517
E4: 3,9                                  #  8 pairs
E8: 6,7,5,9                              # reduction candidate for 6,7
E8: 6,7 => CTR
* .7652.193.91763824.2319.765.1.83..46.8.645371634.17.58762351489158479632.4.286517
E8: 5,9                                  #  8 pairs
* PAIR E3: 6,9 BLK 2
F1: 6,9,1,4,7,8                          # reduction candidate for 6,9
F1: 6,9                                  #  8 pairs
D3: 6,9,1,4,8                            # reduction candidate for 6,9
D3: 6,9                                  #  9 pairs
F3: 6,9,1,4,8                            # reduction candidate for 6,9
F3: 6,9                                  #  9 pairs
* PAIR E3: 6,9 ROW 3
H3: 6,9,2,5,8                            # reduction candidate for 6,9
H3: 6,9                                  # 10 pairs
I3: 6,9,3,5                              # reduction candidate for 6,9
I3: 6,9                                  # 10 pairs
* PAIR E3: 6,9 COL E
E4: 6,9,3,7                              # reduction candidate for 6,9
E4: 6,9 => SOLVED
* 476529183895173624321864795517398246289645371634712958752431869168957432943286517
E4: 3,7                                  #  8 pairs
E7: 6,9,3,5                              # reduction candidate for 6,9
E7: 6,9 => CTR
* 47.529863.96.73124.2..6.795.1..3.649.8.645371634917258752391486168754932.4.286517
E7: 3,5                                  #  8 pairs
E8: 6,9,5,7                              # reduction candidate for 6,9
E8: 6,9 => CTR
* .7.529.63.96.73.24.2..6.795.1..3..46.8.645371634.1..58762351489158.9.632.4.286517
E8: 5,7                                  #  8 pairs
* PAIR A5: 2,9 BLK 4
A4: 2,9,3,5                              # reduction candidate for 2,9
A4: 2,9                                  # 12 pairs
A4: 3,5                                  #  8 pairs
* PAIR A5: 2,9 ROW 5
D5: 2,9,6,7                              # reduction candidate for 2,9
D5: 2,9 => CTR
* .7.52.....9...3..4.3..9.7...1.....4..87.45361624319578752.3....168.5..32.4..82617
D5: 6,7                                  #  8 pairs
H5: 2,9,6,7                              # reduction candidate for 2,9
H5: 2,9                                  #  9 pairs
* PAIR C5: 7,9 BLK 4
C4: 7,9,3,5                              # reduction candidate for 7,9
C4: 7,9                                  # 11 pairs
C4: 3,5                                  #  9 pairs
* PAIR C5: 7,9 ROW 5
D5: 7,9,2,6                              # reduction candidate for 7,9
D5: 7,9                                  # 12 pairs
H5: 7,9,2,6                              # reduction candidate for 7,9
H5: 7,9                                  #  9 pairs
* PAIR B8: 5,6 BLK 7
B7: 5,6,3                                # reduction candidate for 5,6
B7: 5,6                                  # 13 pairs
C9: 5,6,3,9                              # reduction candidate for 5,6
C9: 5,6 => CTR
* ...52.....9...3..4......7...1..3..4.28..453.1634.1...87.2......1.8....3294.382.17
C9: 3,9                                  #  9 pairs
* PAIR B8: 5,6 ROW 8
E8: 5,6,7,9                              # reduction candidate for 5,6
E8: 5,6                                  #  9 pairs
G8: 5,6,4,9                              # reduction candidate for 5,6
G8: 5,6 => CTR
* 476528193895.63.2432..9.765517.3..46289645371634.1..58762351489158.7.632943286517
G8: 4,9                                  #  8 pairs
* PAIR B8: 5,6 COL B
B3: 5,6,2,3                              # reduction candidate for 5,6
B3: 5,6 => CTR
* ...52.....9...3..4......7...1.....4..8..453.162431...87.2.3....1.8.5..32.4..8..17
B3: 2,3                                  #  8 pairs
* PAIR F9: 2,6 BLK 8
D9: 2,6,3                                # reduction candidate for 2,6
D9: 3 => CTR
* ...52.....9...3..4......7...1..3..4..8..453.1634.1...87.2......1.8....32.4.382.17
D9: 2,6                                  # 13 pairs
* PAIR F9: 2,6 COL F
F4: 2,6,7,8,9                            # reduction candidate for 2,6
F4: 2,6                                  #  9 pairs
F4: 7,8,9                                #  7 pairs
* PAIR G9: 5,6 BLK 9
G7: 5,6,4,8,9                            # reduction candidate for 5,6
G7: 5,6                                  # 19 pairs
H7: 5,6,8,9                              # reduction candidate for 5,6
H7: 5,6                                  # 12 pairs
I7: 5,6,9                                # reduction candidate for 5,6
I7: 5,6                                  # 10 pairs
G8: 5,6,4,9                              # reduction candidate for 5,6
G8: 5,6 => CTR
* 476528193895.63.2432..9.765517.3..46289645371634.1..58762351489158.7.632943286517
G8: 4,9                                  #  8 pairs
* PAIR G9: 5,6 ROW 9
C9: 5,6,3,9                              # reduction candidate for 5,6
C9: 5,6 => CTR
* ...52.....9...3..4......7...1..3..4.28..453.1634.1...87.2......1.8....3294.382.17
C9: 3,9                                  #  9 pairs
* PAIR G9: 5,6 COL G
G2: 5,6,1,2,8                            # reduction candidate for 5,6
G2: 5,6                                  # 15 pairs
G4: 5,6,2,9                              # reduction candidate for 5,6
G4: 5,6                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-055-base-pr-000.dot
* REASONING
* DIS # E4: 6,7 => CTR => E4: 3,9
* DIS # E8: 6,7 => CTR => E8: 5,9
* PRF # E4: 6,9 => SOL
* DIS # E7: 6,9 => CTR => E7: 3,5
* DIS # E8: 6,9 => CTR => E8: 5,7
* DIS # D5: 2,9 => CTR => D5: 6,7
* DIS # C9: 5,6 => CTR => C9: 3,9
* DIS # G8: 5,6 => CTR => G8: 4,9
* DIS # B3: 5,6 => CTR => B3: 2,3
* DIS # D9: 3 => CTR => D9: 2,6
* DIS # G8: 5,6 => CTR => G8: 4,9
* DIS # C9: 5,6 => CTR => C9: 3,9
* CNT  12 HDP CHAINS /  49 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,B8,C5,E2,E3,F9,G9)
* ...52.....9...3..4......7...1.....4..8..453.16.4.1...87.2......1.8....32.4..8..17
* PAIR E2: 6,7 BLK 2
F1: 6,7,1,4,8,9                          # reduction candidate for 6,7
F1: 6,7                                  #  8 pairs
D2: 6,7,1,8                              # reduction candidate for 6,7
D2: 6,7                                  #  8 pairs
* PAIR E2: 6,7 ROW 2
C2: 6,7,1,5                              # reduction candidate for 6,7
C2: 6,7                                  #  9 pairs
C2: 1,5                                  #  8 pairs
* PAIR E2: 6,7 COL E
E4: 6,7,3,9                              # reduction candidate for 6,7
E4: 6,7 => CTR
* .7.52...3.9..63..4....9.7.5.17....4..896453716.4.1..58752.3....168.5..32943286517
E8: 6,7,5,9                              # reduction candidate for 6,7
E8: 6,7 => CTR
* .7652.193.91763824.2319.765.1.83..46.8.645371634.17.58762351489158479632.4.286517
* PAIR RESTART
* PAIR E3: 6,9 BLK 2
F1: 6,9,1,4,8                            # reduction candidate for 6,9
F1: 6,9                                  # 10 pairs
D3: 6,9,1,4,8                            # reduction candidate for 6,9
D3: 6,9                                  # 11 pairs
F3: 6,9,1,4,8                            # reduction candidate for 6,9
F3: 6,9                                  # 11 pairs
* PAIR E3: 6,9 ROW 3
H3: 6,9,2,5,8                            # reduction candidate for 6,9
H3: 6,9                                  # 11 pairs
I3: 6,9,3,5                              # reduction candidate for 6,9
I3: 6,9                                  # 11 pairs
* PAIR E3: 6,9 COL E
E7: 6,9,3,5                              # reduction candidate for 6,9
E7: 6,9 => CTR
* 47.529863.96.73124.2..6.795.1..3.649.8.645371634917258752391486168754932.4.286517
* PAIR RESTART
* PAIR A5: 2,9 BLK 4
A4: 2,9,3,5                              # reduction candidate for 2,9
A4: 2,9                                  # 19 pairs
A4: 3,5                                  # 10 pairs
* PAIR A5: 2,9 ROW 5
D5: 2,9,6,7                              # reduction candidate for 2,9
D5: 2,9 => CTR
* .7.52.....9..73..4....6.7...1.....4..87.453616.4.1..787.2......1.8....32.4..8..17
H5: 2,9,6,7                              # reduction candidate for 2,9
H5: 2,9                                  # 16 pairs
* RESTART
* PAIR A5: 2,9 ROW 5
H5: 2,9,6,7                              # reduction candidate for 2,9
H5: 2,9                                  # 16 pairs
H5: 6,7                                  # 11 pairs
* PAIR RESTART
* PAIR A5: 2,9 BLK 4
A4: 2,9,3,5                              # reduction candidate for 2,9
A4: 2,9                                  # 19 pairs
A4: 3,5                                  # 11 pairs
* PAIR A5: 2,9 ROW 5
H5: 2,9,6,7                              # reduction candidate for 2,9
H5: 2,9                                  # 16 pairs
H5: 6,7                                  # 11 pairs
* PAIR C5: 7,9 BLK 4
C4: 7,9,3,5                              # reduction candidate for 7,9
C4: 3,5                                  # 16 pairs
C4: 7,9                                  # 14 pairs
* PAIR C5: 7,9 ROW 5
H5: 7,9,2,6                              # reduction candidate for 7,9
H5: 2,6                                  # 15 pairs
H5: 7,9                                  # 11 pairs
* PAIR B8: 5,6 BLK 7
B7: 5,6,3                                # reduction candidate for 5,6
B7: 5,6 => SOLVED
* 476529183895173624321864795517398246289645371634712958752431869168957432943286517
* DURATION: 0:00:21.276824  START: 00:01:43.839183  END: 00:02:05.116007 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-055-base-pr-001.dot
* REASONING
* DIS # E4: 6,7 => CTR => E4: 3,9
* DIS E4: 3,9 # E8: 6,7 => CTR => E8: 5,9
* DIS E4: 3,9 + E8: 5,9 # E7: 6,9 => CTR => E7: 3,5
* DIS E4: 3,9 + E8: 5,9 + E7: 3,5 # D5: 2,9 => CTR => D5: 6,7
* PRF E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # B7: 5,6 => SOL
* STA E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 + B7: 5,6
* CNT   5 HDP CHAINS /  27 HYP OPENED

Header Info

Top 95 Sudokus 055
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 476529183895173624321864795517398246289645371634712958752431869168957432943286517 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 # F1: 6,7 => UNS
* INC # D2: 6,7 => UNS
* INC # C2: 6,7 => UNS
* INC # C2: 1,5 => UNS
* DIS # E4: 6,7 => CTR => E4: 3,9
* INC # E4: 3,9 => UNS
* DIS # E8: 6,7 => CTR => E8: 5,9
* INC # E8: 5,9 => UNS
* INC # F1: 6,9 => UNS
* INC # D3: 6,9 => UNS
* INC # F3: 6,9 => UNS
* INC # H3: 6,9 => UNS
* INC # I3: 6,9 => UNS
* PRF # E4: 6,9 => SOL
* INC # E4: 3,7 => UNS
* DIS # E7: 6,9 => CTR => E7: 3,5
* INC # E7: 3,5 => UNS
* DIS # E8: 6,9 => CTR => E8: 5,7
* INC # E8: 5,7 => UNS
* INC # A4: 2,9 => UNS
* INC # A4: 3,5 => UNS
* DIS # D5: 2,9 => CTR => D5: 6,7
* INC # D5: 6,7 => UNS
* INC # H5: 2,9 => UNS
* INC # C4: 7,9 => UNS
* INC # C4: 3,5 => UNS
* INC # D5: 7,9 => UNS
* INC # H5: 7,9 => UNS
* INC # B7: 5,6 => UNS
* DIS # C9: 5,6 => CTR => C9: 3,9
* INC # C9: 3,9 => UNS
* INC # E8: 5,6 => UNS
* DIS # G8: 5,6 => CTR => G8: 4,9
* INC # G8: 4,9 => UNS
* DIS # B3: 5,6 => CTR => B3: 2,3
* INC # B3: 2,3 => UNS
* INC # D9: 2,6 => UNS
* DIS # D9: 3 => CTR => D9: 2,6
* INC # F4: 2,6 => UNS
* INC # F4: 7,8,9 => UNS
* INC # G7: 5,6 => UNS
* INC # H7: 5,6 => UNS
* INC # I7: 5,6 => UNS
* DIS # G8: 5,6 => CTR => G8: 4,9
* INC # G8: 4,9 => UNS
* DIS # C9: 5,6 => CTR => C9: 3,9
* INC # C9: 3,9 => UNS
* INC # G2: 5,6 => UNS
* INC # G4: 5,6 => UNS
* CNT  49 HDP CHAINS /  49 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # F1: 6,7 => UNS
* INC # D2: 6,7 => UNS
* INC # C2: 6,7 => UNS
* INC # C2: 1,5 => UNS
* DIS # E4: 6,7 => CTR => E4: 3,9
* DIS E4: 3,9 # E8: 6,7 => CTR => E8: 5,9
* INC E4: 3,9 + E8: 5,9 # F1: 6,9 => UNS
* INC E4: 3,9 + E8: 5,9 # D3: 6,9 => UNS
* INC E4: 3,9 + E8: 5,9 # F3: 6,9 => UNS
* INC E4: 3,9 + E8: 5,9 # H3: 6,9 => UNS
* INC E4: 3,9 + E8: 5,9 # I3: 6,9 => UNS
* DIS E4: 3,9 + E8: 5,9 # E7: 6,9 => CTR => E7: 3,5
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 # A4: 2,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 # A4: 3,5 => UNS
* DIS E4: 3,9 + E8: 5,9 + E7: 3,5 # D5: 2,9 => CTR => D5: 6,7
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 2,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 2,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 6,7 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # A4: 2,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # A4: 3,5 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 2,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 6,7 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # C4: 7,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # C4: 3,5 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 7,9 => UNS
* INC E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # H5: 2,6 => UNS
* PRF E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 # B7: 5,6 => SOL
* STA E4: 3,9 + E8: 5,9 + E7: 3,5 + D5: 6,7 + B7: 5,6
* CNT  27 HDP CHAINS /  27 HYP OPENED