Analysis of xx-top95-077-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 1.......3.6.3..7...7...5..121.7...9...7........8.1..2....8.64....9.2..6....4..... initial

Autosolve

position: 1...78..3.6.3.17...73..5..12157..89...758213...8.1.527..18.647...912736.7.64...1. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # E3: 4,9 => SOL
* DIS # E3: 6 => CTR => E3: 4,9
* PRF # G1: 2,9 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # A5: 4,9 => SOL
* DIS # A5: 6 => CTR => A5: 4,9
* DIS # A6: 3,4 => CTR => A6: 6
* PRF # A6: 6 => SOL
* DIS # D3: 6,9 => CTR => D3: 2
* PRF # A5: 4,6 => SOL
* DIS # A5: 9 => CTR => A5: 4,6
* DIS # B7: 3,5 => CTR => B7: 2
* DIS # B9: 3,5 => CTR => B9: 2,8
* PRF # E7: 3,5 => SOL
* DIS # E7: 9 => CTR => E7: 3,5
* PRF # E9: 3,9 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # B8: 4 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # G1: 2,9 => SOL
* CNT  20 HDP CHAINS /  38 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 # E3: 4,9 => SOL
* STA E3: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

1.......3.6.3..7...7...5..121.7...9...7........8.1..2....8.64....9.2..6....4..... initial
1...78..3.6.3.17...73..5..12157..89...758213...8.1.527..18.647...912736.7.64...1. autosolve
152678943864391752973245681215763894497582136638914527321856479549127368786439215 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (23)
B1: 5,9
C1: 2,4
A2: 5,8
C2: 2,4
A3: 8,9
E2: 4,9
H1: 4,5
H2: 5,8
I2: 2,9
H3: 4,8
B5: 4,9
B6: 3,4
E4: 3,6
F4: 3,4
D6: 6,9
F6: 4,9
I4: 4,6
I5: 4,6
A7: 3,5
A8: 4,5
F9: 3,9
I8: 5,8
G9: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C1,C2: 2.. / C1 = 2  =>  0 pairs (*) / C2 = 2  =>  0 pairs (X)
D1,D3: 2.. / D1 = 2  =>  0 pairs (X) / D3 = 2  => 25 pairs (_)
B7,B9: 2.. / B7 = 2  => 24 pairs (_) / B9 = 2  =>  0 pairs (X)
C2,I2: 2.. / C2 = 2  =>  0 pairs (X) / I2 = 2  =>  0 pairs (_)
D3,G3: 2.. / D3 = 2  => 25 pairs (_) / G3 = 2  =>  0 pairs (X)
B7,I7: 2.. / B7 = 2  => 24 pairs (_) / I7 = 2  =>  0 pairs (X)
A6,B6: 3.. / A6 = 3  =>  0 pairs (X) / B6 = 3  => 24 pairs (_)
E4,F4: 3.. / E4 = 3  =>  0 pairs (X) / F4 = 3  =>  0 pairs (_)
A6,A7: 3.. / A6 = 3  =>  0 pairs (X) / A7 = 3  => 24 pairs (_)
F4,F9: 3.. / F4 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
C1,C2: 4.. / C1 = 4  =>  0 pairs (X) / C2 = 4  =>  0 pairs (_)
E2,E3: 4.. / E2 = 4  =>  0 pairs (X) / E3 = 4  =>  0 pairs (_)
H1,H3: 4.. / H1 = 4  =>  0 pairs (*) / H3 = 4  =>  0 pairs (X)
F4,F6: 4.. / F4 = 4  =>  0 pairs (X) / F6 = 4  =>  0 pairs (_)
I4,I5: 4.. / I4 = 4  =>  0 pairs (*) / I5 = 4  =>  0 pairs (X)
A8,B8: 4.. / A8 = 4  => 25 pairs (_) / B8 = 4  =>  0 pairs (*)
C1,H1: 4.. / C1 = 4  =>  0 pairs (X) / H1 = 4  =>  0 pairs (_)
C2,E2: 4.. / C2 = 4  =>  0 pairs (*) / E2 = 4  =>  0 pairs (X)
E3,H3: 4.. / E3 = 4  =>  0 pairs (*) / H3 = 4  =>  0 pairs (X)
F4,I4: 4.. / F4 = 4  =>  0 pairs (X) / I4 = 4  =>  0 pairs (_)
B1,A2: 5.. / B1 = 5  =>  0 pairs (*) / A2 = 5  =>  0 pairs (X)
H1,H2: 5.. / H1 = 5  =>  0 pairs (X) / H2 = 5  =>  0 pairs (_)
E7,E9: 5.. / E7 = 5  =>  0 pairs (*) / E9 = 5  =>  0 pairs (X)
B1,H1: 5.. / B1 = 5  =>  0 pairs (*) / H1 = 5  =>  0 pairs (X)
A2,H2: 5.. / A2 = 5  =>  0 pairs (X) / H2 = 5  =>  0 pairs (_)
G1,G3: 6.. / G1 = 6  => 25 pairs (_) / G3 = 6  =>  0 pairs (*)
A5,A6: 6.. / A5 = 6  =>  0 pairs (X) / A6 = 6  =>  0 pairs (_)
E4,D6: 6.. / E4 = 6  =>  0 pairs (*) / D6 = 6  =>  0 pairs (X)
I4,I5: 6.. / I4 = 6  =>  0 pairs (X) / I5 = 6  =>  0 pairs (_)
D1,G1: 6.. / D1 = 6  =>  0 pairs (*) / G1 = 6  =>  0 pairs (X)
E4,I4: 6.. / E4 = 6  =>  0 pairs (*) / I4 = 6  =>  0 pairs (X)
A5,I5: 6.. / A5 = 6  =>  0 pairs (X) / I5 = 6  =>  0 pairs (_)
A6,D6: 6.. / A6 = 6  =>  0 pairs (*) / D6 = 6  =>  0 pairs (X)
E3,E4: 6.. / E3 = 6  =>  0 pairs (X) / E4 = 6  =>  0 pairs (_)
A2,A3: 8.. / A2 = 8  =>  0 pairs (*) / A3 = 8  =>  0 pairs (X)
H2,H3: 8.. / H2 = 8  =>  0 pairs (X) / H3 = 8  =>  0 pairs (_)
B8,B9: 8.. / B8 = 8  => 24 pairs (_) / B9 = 8  => 24 pairs (_)
I8,I9: 8.. / I8 = 8  => 24 pairs (_) / I9 = 8  => 24 pairs (_)
A2,H2: 8.. / A2 = 8  =>  0 pairs (*) / H2 = 8  =>  0 pairs (X)
A3,H3: 8.. / A3 = 8  =>  0 pairs (X) / H3 = 8  =>  0 pairs (_)
B8,I8: 8.. / B8 = 8  => 24 pairs (_) / I8 = 8  => 24 pairs (_)
B9,I9: 8.. / B9 = 8  => 24 pairs (_) / I9 = 8  => 24 pairs (_)
B1,A3: 9.. / B1 = 9  =>  0 pairs (X) / A3 = 9  =>  0 pairs (_)
A5,B5: 9.. / A5 = 9  =>  0 pairs (X) / B5 = 9  =>  0 pairs (_)
D6,F6: 9.. / D6 = 9  =>  0 pairs (*) / F6 = 9  =>  0 pairs (X)
E2,I2: 9.. / E2 = 9  =>  0 pairs (*) / I2 = 9  =>  0 pairs (X)
E7,I7: 9.. / E7 = 9  =>  0 pairs (X) / I7 = 9  =>  0 pairs (_)
A3,A5: 9.. / A3 = 9  =>  0 pairs (*) / A5 = 9  =>  0 pairs (X)
B1,B5: 9.. / B1 = 9  =>  0 pairs (X) / B5 = 9  =>  0 pairs (_)
F6,F9: 9.. / F6 = 9  =>  0 pairs (X) / F9 = 9  =>  0 pairs (_)
* DURATION: 0:01:52.645095  START: 00:42:46.481606  END: 00:44:39.126701 2017-05-04
* CP COUNT: (50)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,A7,A8,B1,B5,B6,C1,C2,D6,E2,E4,F4,F6,F9,G9,H1,H2,H3,I2,I4,I5,I8)
* 1...78..3.6.3.17...73..5..12157..89...758213...8.1.527..18.647...912736.7.64...1.
* PAIR E2: 4,9 BLK 2
E3: 4,9,6                                # reduction candidate for 4,9
E3: 4,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
E3: 6 => CTR
* 1...78..3.6.3417.9.73.65241215734896697582134..861.527..18.647...912736.7.64...1.
* PAIR I2: 2,9 BLK 3
G1: 2,9,6                                # reduction candidate for 2,9
G1: 2,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
G1: 6                                    # 25 pairs
G3: 2,9,6                                # reduction candidate for 2,9
G3: 2,9                                  # 25 pairs
* PAIR I2: 2,9 COL I
I7: 2,9,5                                # reduction candidate for 2,9
I7: 2,9                                  # 25 pairs
I9: 2,9,5,8                              # reduction candidate for 2,9
I9: 2,9 => CTR
* 15..786438643.17...73..5..1215734896697582134..8619527.21896475..9127368786453.1.
I9: 5,8                                  # 25 pairs
* PAIR B5: 4,9 BLK 4
A5: 4,9,6                                # reduction candidate for 4,9
A5: 4,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
A5: 6 => CTR
* 1...78..3.6.3.17..973..5.812157..89.697582134..8619527..18.647...912736.7.64.3.1.
* PAIR B6: 3,4 BLK 4
A6: 3,4,6                                # reduction candidate for 3,4
A6: 3,4 => CTR
* 15..786438643917...73..5..12157..89.697582134..8619527..18.647...912736.7.64.3.1.
A6: 6 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
* PAIR D6: 6,9 COL D
D1: 6,9,2                                # reduction candidate for 6,9
D1: 6,9                                  # 25 pairs
D3: 6,9,2                                # reduction candidate for 6,9
D3: 6,9 => CTR
* 194278653562341789873965241215734896..758213...8.1.527..189647...912736.7.645391.
D3: 2                                    # 25 pairs
* PAIR I5: 4,6 ROW 5
A5: 4,6,9                                # reduction candidate for 4,6
A5: 4,6 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
A5: 9 => CTR
* 19..7865356.3.1782873..5..12157..89.9475821366389145273.18.647.4.912736.7.64.921.
* PAIR A7: 3,5 BLK 7
B7: 3,5,2                                # reduction candidate for 3,5
B7: 3,5 => CTR
* 1.4.78.53562341789873965241215734896..758213...8.19527..1896472.89127365726453918
B7: 2                                    # 24 pairs
B9: 3,5,2,8                              # reduction candidate for 3,5
B9: 3,5 => CTR
* 1.2.78.43.64391752.73245681215763894.47582136638.1.527.218.64794891273657.64..218
B9: 2,8                                  # 25 pairs
* PAIR A7: 3,5 ROW 7
E7: 3,5,9                                # reduction candidate for 3,5
E7: 3,5 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
E7: 9 => CTR
* 1...78..3.6.3417.9.73.65241215734896697582134..861.527..189647...912736.7.6453.1.
* PAIR A8: 4,5 BLK 7
B8: 4,5,8                                # reduction candidate for 4,5
B8: 8                                    # 24 pairs
B8: 4,5                                  # 24 pairs
* PAIR F9: 3,9 BLK 8
E7: 3,9,5                                # reduction candidate for 3,9
E7: 3,9                                  # 24 pairs
E9: 3,9,5                                # reduction candidate for 3,9
E9: 3,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
E9: 5                                    # 24 pairs
* PAIR I8: 5,8 BLK 9
I9: 5,8,2,9                              # reduction candidate for 5,8
I9: 2,9 => CTR
* 15..786438643.17...73..5..1215734896697582134..8619527.21896475..9127368786453.1.
I9: 5,8                                  # 25 pairs
* PAIR I8: 5,8 ROW 8
B8: 5,8,4                                # reduction candidate for 5,8
B8: 4 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
B8: 5,8                                  # 25 pairs
* PAIR G9: 2,9 BLK 9
I7: 2,9,5                                # reduction candidate for 2,9
I7: 2,9                                  # 25 pairs
I9: 2,9,5,8                              # reduction candidate for 2,9
I9: 2,9 => CTR
* 15..786438643.17...73..5..1215734896697582134..8619527.21896475..9127368786453.1.
I9: 5,8                                  # 25 pairs
* PAIR G9: 2,9 COL G
G1: 2,9,6                                # reduction candidate for 2,9
G1: 2,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
G1: 6                                    # 25 pairs
G3: 2,9,6                                # reduction candidate for 2,9
G3: 2,9                                  # 25 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-077-base-pr-000.dot
* REASONING
* PRF # E3: 4,9 => SOL
* DIS # E3: 6 => CTR => E3: 4,9
* PRF # G1: 2,9 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # A5: 4,9 => SOL
* DIS # A5: 6 => CTR => A5: 4,9
* DIS # A6: 3,4 => CTR => A6: 6
* PRF # A6: 6 => SOL
* DIS # D3: 6,9 => CTR => D3: 2
* PRF # A5: 4,6 => SOL
* DIS # A5: 9 => CTR => A5: 4,6
* DIS # B7: 3,5 => CTR => B7: 2
* DIS # B9: 3,5 => CTR => B9: 2,8
* PRF # E7: 3,5 => SOL
* DIS # E7: 9 => CTR => E7: 3,5
* PRF # E9: 3,9 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # B8: 4 => SOL
* DIS # I9: 2,9 => CTR => I9: 5,8
* PRF # G1: 2,9 => SOL
* CNT  20 HDP CHAINS /  38 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,A7,A8,B1,B5,B6,C1,C2,D6,E2,E4,F4,F6,F9,G9,H1,H2,H3,I2,I4,I5,I8)
* 1...78..3.6.3.17...73..5..12157..89...758213...8.1.527..18.647...912736.7.64...1.
* PAIR E2: 4,9 BLK 2
E3: 4,9,6                                # reduction candidate for 4,9
E3: 4,9 => SOLVED
* 152678943864391752973245681215763894497582136638914527321856479549127368786439215
* DURATION: 0:00:02.659457  START: 00:45:28.739097  END: 00:45:31.398554 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-077-base-pr-001.dot
* REASONING
* PRF # E3: 4,9 => SOL
* STA E3: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 95 Sudokus 077
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 152678943864391752973245681215763894497582136638914527321856479549127368786439215 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 # E3: 4,9 => SOL
* DIS # E3: 6 => CTR => E3: 4,9
* PRF # G1: 2,9 => SOL
* INC # G1: 6 => UNS
* INC # G3: 2,9 => UNS
* INC # I7: 2,9 => UNS
* DIS # I9: 2,9 => CTR => I9: 5,8
* INC # I9: 5,8 => UNS
* PRF # A5: 4,9 => SOL
* DIS # A5: 6 => CTR => A5: 4,9
* DIS # A6: 3,4 => CTR => A6: 6
* PRF # A6: 6 => SOL
* INC # D1: 6,9 => UNS
* DIS # D3: 6,9 => CTR => D3: 2
* INC # D3: 2 => UNS
* PRF # A5: 4,6 => SOL
* DIS # A5: 9 => CTR => A5: 4,6
* DIS # B7: 3,5 => CTR => B7: 2
* INC # B7: 2 => UNS
* DIS # B9: 3,5 => CTR => B9: 2,8
* INC # B9: 2,8 => UNS
* PRF # E7: 3,5 => SOL
* DIS # E7: 9 => CTR => E7: 3,5
* INC # B8: 4,5 => UNS
* INC # B8: 8 => UNS
* INC # E7: 3,9 => UNS
* PRF # E9: 3,9 => SOL
* INC # E9: 5 => UNS
* INC # I9: 5,8 => UNS
* DIS # I9: 2,9 => CTR => I9: 5,8
* INC # B8: 5,8 => UNS
* PRF # B8: 4 => SOL
* INC # I7: 2,9 => UNS
* DIS # I9: 2,9 => CTR => I9: 5,8
* INC # I9: 5,8 => UNS
* PRF # G1: 2,9 => SOL
* INC # G1: 6 => UNS
* INC # G3: 2,9 => UNS
* CNT  38 HDP CHAINS /  38 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # E3: 4,9 => SOL
* STA E3: 4,9
* CNT   1 HDP CHAINS /   1 HYP OPENED