Analysis of xx-top95-092-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2.3.......6..8.9.83.5........2...8.7.9..5........6..4.......1...1...4.22..7..8.9 initial

Autosolve

position: 92.3....8..64.8.9.83.5........2...8.7.9..5.....2..6..4..8....1...1...4.22..7..8.9 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A4: 1,5 => CTR => A4: 3,4,6
* DIS # E3: 2,7 => CTR => E3: 1,6,9
* DIS # G4: 3,5 => CTR => G4: 1,6,7,9
* DIS # A7: 3,5 => CTR => A7: 4,6
* DIS # E9: 3,5 => CTR => E9: 1,4
* PRF # F7: 3,9 => SOL
* CNT   6 HDP CHAINS /  46 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 # A4: 1,5 => CTR => A4: 3,4,6
* DIS A4: 3,4,6 # A6: 3 => CTR => A6: 1,5
* DIS A4: 3,4,6 + A6: 1,5 # B6: 1,5 => CTR => B6: 8
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 # E1: 1,7 => CTR => E1: 6
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 # E3: 1,7 => CTR => E3: 2,9
* PRF A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # G1: 1,7 => SOL
* STA A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 + G1: 1,7
* CNT   6 HDP CHAINS /  20 HYP OPENED

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

Details

Positions

.2.3.......6..8.9.83.5........2...8.7.9..5........6..4.......1...1...4.22..7..8.9 initial
92.3....8..64.8.9.83.5........2...8.7.9..5.....2..6..4..8....1...1...4.22..7..8.9 autosolve
924361758156478293837592641613247985749185326582936174498623517371859462265714839 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
C1: 4,7
A2: 1,5
B2: 1,5
C3: 4,7
F1: 1,7
E2: 2,7
I2: 3,7
C4: 3,5
D5: 1,8
B7: 7,9
B8: 7,9
C9: 3,5
D7: 6,9
F8: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,B2: 1.. / A2 = 1  => 16 pairs (_) / B2 = 1  => 16 pairs (_)
D5,D6: 1.. / D5 = 1  => 18 pairs (_) / D6 = 1  => 18 pairs (_)
E9,F9: 1.. / E9 = 1  => 16 pairs (_) / F9 = 1  =>  0 pairs (X)
G5,H5: 2.. / G5 = 2  => 17 pairs (_) / H5 = 2  => 14 pairs (_)
E7,F7: 2.. / E7 = 2  =>  0 pairs (*) / F7 = 2  =>  0 pairs (X)
E2,G2: 2.. / E2 = 2  => 15 pairs (_) / G2 = 2  => 16 pairs (_)
F3,F7: 2.. / F3 = 2  =>  0 pairs (*) / F7 = 2  =>  0 pairs (X)
H3,H5: 2.. / H3 = 2  => 17 pairs (_) / H5 = 2  => 14 pairs (_)
G2,I2: 3.. / G2 = 3  => 13 pairs (_) / I2 = 3  => 15 pairs (_)
C4,C9: 3.. / C4 = 3  => 18 pairs (_) / C9 = 3  => 23 pairs (_)
C1,C3: 4.. / C1 = 4  => 13 pairs (_) / C3 = 4  => 12 pairs (_)
H1,H3: 4.. / H1 = 4  => 12 pairs (_) / H3 = 4  => 13 pairs (_)
A7,B9: 4.. / A7 = 4  => 17 pairs (_) / B9 = 4  =>  0 pairs (X)
C1,H1: 4.. / C1 = 4  => 13 pairs (_) / H1 = 4  => 12 pairs (_)
C3,H3: 4.. / C3 = 4  => 12 pairs (_) / H3 = 4  => 13 pairs (_)
B5,E5: 4.. / B5 = 4  => 19 pairs (_) / E5 = 4  => 15 pairs (_)
A4,A7: 4.. / A4 = 4  =>  0 pairs (X) / A7 = 4  => 17 pairs (_)
A2,B2: 5.. / A2 = 5  => 16 pairs (_) / B2 = 5  => 16 pairs (_)
G1,H1: 5.. / G1 = 5  => 14 pairs (_) / H1 = 5  => 15 pairs (_)
C4,C9: 5.. / C4 = 5  => 23 pairs (_) / C9 = 5  => 18 pairs (_)
I4,I7: 5.. / I4 = 5  => 19 pairs (_) / I7 = 5  => 15 pairs (_)
E1,E3: 6.. / E1 = 6  => 14 pairs (_) / E3 = 6  => 18 pairs (_)
D7,D8: 6.. / D7 = 6  => 15 pairs (_) / D8 = 6  =>  0 pairs (X)
B9,H9: 6.. / B9 = 6  => 18 pairs (_) / H9 = 6  => 16 pairs (_)
C1,C3: 7.. / C1 = 7  => 12 pairs (_) / C3 = 7  => 13 pairs (_)
B7,B8: 7.. / B7 = 7  => 16 pairs (_) / B8 = 7  => 13 pairs (_)
B8,H8: 7.. / B8 = 7  => 13 pairs (_) / H8 = 7  => 16 pairs (_)
B5,B6: 8.. / B5 = 8  => 20 pairs (_) / B6 = 8  => 15 pairs (_)
D8,E8: 8.. / D8 = 8  => 17 pairs (_) / E8 = 8  => 19 pairs (_)
E3,F3: 9.. / E3 = 9  => 15 pairs (_) / F3 = 9  => 16 pairs (_)
G4,G6: 9.. / G4 = 9  => 14 pairs (_) / G6 = 9  => 20 pairs (_)
B7,B8: 9.. / B7 = 9  => 13 pairs (_) / B8 = 9  => 16 pairs (_)
* DURATION: 0:00:45.431826  START: 01:09:23.586809  END: 01:10:09.018635 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B2,B7,B8,C1,C3,C4,C9,D5,D7,E2,F1,F8,I2)
* 92.3....8..64.8.9.83.5........2...8.7.9..5.....2..6..4..8....1...1...4.22..7..8.9
* PAIR C1: 4,7 ROW 1
H1: 4,7,5,6                              # reduction candidate for 4,7
H1: 4,7                                  # 15 pairs
H1: 5,6                                  # 14 pairs
* PAIR A2: 1,5 COL A
A4: 1,5,3,4,6                            # reduction candidate for 1,5
A4: 1,5 => CTR
* 92.3615.851642879383.5976211652..9877491852363829761544.86.2.156.185.4.22537..869
A4: 3,4,6                                # 14 pairs
A6: 1,5,3                                # reduction candidate for 1,5
A6: 1,5                                  # 18 pairs
* PAIR B2: 1,5 COL B
B4: 1,5,4,6                              # reduction candidate for 1,5
B4: 1,5                                  # 19 pairs
B6: 1,5,8                                # reduction candidate for 1,5
B6: 1,5                                  # 20 pairs
* PAIR C3: 4,7 ROW 3
H3: 4,7,2,6                              # reduction candidate for 4,7
H3: 4,7                                  # 16 pairs
H3: 2,6                                  # 13 pairs
* PAIR F1: 1,7 BLK 2
E1: 1,7,6                                # reduction candidate for 1,7
E1: 1,7                                  # 18 pairs
E3: 1,7,2,6,9                            # reduction candidate for 1,7
E3: 1,7                                  # 20 pairs
F3: 1,7,2,9                              # reduction candidate for 1,7
F3: 1,7                                  # 19 pairs
* PAIR F1: 1,7 ROW 1
G1: 1,7,5,6                              # reduction candidate for 1,7
G1: 1,7                                  # 16 pairs
G1: 5,6                                  # 15 pairs
* PAIR E2: 2,7 BLK 2
E3: 2,7,1,6,9                            # reduction candidate for 2,7
E3: 2,7 => CTR
* 92.361..85164.8.9383.5.9..7..52.798.7.9..5....82..6..44.8692315691853472253714869
E3: 1,6,9                                # 14 pairs
F3: 2,7,1,9                              # reduction candidate for 2,7
F3: 2,7                                  # 16 pairs
* PAIR E2: 2,7 ROW 2
G2: 2,7,3                                # reduction candidate for 2,7
G2: 2,7                                  # 15 pairs
G2: 3                                    # 13 pairs
* PAIR I2: 3,7 BLK 3
G2: 3,7,2                                # reduction candidate for 3,7
G2: 2                                    # 16 pairs
G2: 3,7                                  # 15 pairs
* PAIR I2: 3,7 COL I
I4: 3,7,1,5,6                            # reduction candidate for 3,7
I4: 3,7                                  # 18 pairs
I7: 3,7,5,6                              # reduction candidate for 3,7
I7: 3,7                                  # 22 pairs
* PAIR C4: 3,5 BLK 4
A4: 3,5,1,4,6                            # reduction candidate for 3,5
A4: 3,5                                  # 23 pairs
A6: 3,5,1                                # reduction candidate for 3,5
A6: 3,5                                  # 16 pairs
* PAIR C4: 3,5 ROW 4
G4: 3,5,1,6,7,9                          # reduction candidate for 3,5
G4: 3,5 => CTR
* 92.3.7..8156428.9.8375.9.4...5294387749..5.....2..69.4..8....155.1.834.22.3751869
G4: 1,6,7,9                              # 14 pairs
I4: 3,5,1,6,7                            # reduction candidate for 3,5
I4: 3,5                                  # 15 pairs
* PAIR D5: 1,8 BLK 5
D6: 1,8,9                                # reduction candidate for 1,8
D6: 1,8                                  # 19 pairs
D6: 9                                    # 17 pairs
* PAIR D5: 1,8 ROW 5
B5: 1,8,4,6                              # reduction candidate for 1,8
B5: 1,8                                  # 20 pairs
B5: 4,6                                  # 16 pairs
* PAIR C9: 3,5 BLK 7
A7: 3,5,4,6                              # reduction candidate for 3,5
A7: 3,5 => CTR
* 92.3....8..647829383.592...4..23798.7.9.4532.3.2986..459862471.6.1...4.224.7..869
A7: 4,6                                  # 15 pairs
A8: 3,5,6                                # reduction candidate for 3,5
A8: 3,5                                  # 18 pairs
* PAIR C9: 3,5 ROW 9
E9: 3,5,1,4                              # reduction candidate for 3,5
E9: 3,5 => CTR
* 9243.7.58..6428.9.8375.924.4..2...8.7.9..5.2...2..6..4..8..2.1...1..34.224.751869
E9: 1,4                                  # 15 pairs
H9: 3,5,6                                # reduction candidate for 3,5
H9: 3,5                                  # 18 pairs
* PAIR D7: 6,9 BLK 8
D8: 6,9,8                                # reduction candidate for 6,9
D8: 6,9                                  # 19 pairs
D8: 8                                    # 17 pairs
* PAIR F8: 3,9 BLK 8
E7: 3,9,2,4,5                            # reduction candidate for 3,9
E7: 3,9                                  # 23 pairs
F7: 3,9,2,4                              # reduction candidate for 3,9
F7: 3,9 => SOLVED
* 924361758156478293837592641613247985749185326582936174498623517371859462265714839
F7: 2,4                                  # 15 pairs
E8: 3,9,5,8                              # reduction candidate for 3,9
E8: 3,9                                  # 20 pairs
* PAIR F8: 3,9 COL F
F4: 3,9,4,7                              # reduction candidate for 3,9
F4: 3,9                                  # 21 pairs
F4: 4,7                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-092-base-pr-000.dot
* REASONING
* DIS # A4: 1,5 => CTR => A4: 3,4,6
* DIS # E3: 2,7 => CTR => E3: 1,6,9
* DIS # G4: 3,5 => CTR => G4: 1,6,7,9
* DIS # A7: 3,5 => CTR => A7: 4,6
* DIS # E9: 3,5 => CTR => E9: 1,4
* PRF # F7: 3,9 => SOL
* CNT   6 HDP CHAINS /  46 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B2,B7,B8,C1,C3,C4,C9,D5,D7,E2,F1,F8,I2)
* 92.3....8..64.8.9.83.5........2...8.7.9..5.....2..6..4..8....1...1...4.22..7..8.9
* PAIR C1: 4,7 ROW 1
H1: 4,7,5,6                              # reduction candidate for 4,7
H1: 4,7                                  # 15 pairs
H1: 5,6                                  # 14 pairs
* PAIR A2: 1,5 COL A
A4: 1,5,3,4,6                            # reduction candidate for 1,5
A4: 1,5 => CTR
* 92.3615.851642879383.5976211652..9877491852363829761544.86.2.156.185.4.22537..869
A6: 1,5,3                                # reduction candidate for 1,5
A6: 1,5                                  # 18 pairs
* RESTART
* PAIR A2: 1,5 COL A
A6: 1,5,3                                # reduction candidate for 1,5
A6: 3 => CTR
* 92.3.7..8156428.9.8375.9.4...52...8.7.9..5.2.3.2..6..46.89.2.155916..4.22.3751869
* PAIR RESTART
* PAIR B2: 1,5 COL B
B4: 1,5,4,6                              # reduction candidate for 1,5
B4: 1,5                                  # 21 pairs
B6: 1,5,8                                # reduction candidate for 1,5
B6: 1,5 => CTR
* 92.3..5.8..64.8.9.83.5........2...85789145.....2836974..8.52.1..71.8.4522.5714839
* RESTART
* PAIR B2: 1,5 COL B
B4: 1,5,4,6                              # reduction candidate for 1,5
B4: 4,6                                  # 25 pairs
B4: 1,5                                  # 21 pairs
* PAIR RESTART
* PAIR B2: 1,5 COL B
B4: 1,5,4,6                              # reduction candidate for 1,5
B4: 4,6                                  # 25 pairs
B4: 1,5                                  # 21 pairs
* PAIR C3: 4,7 ROW 3
H3: 4,7,2,6                              # reduction candidate for 4,7
H3: 4,7                                  # 21 pairs
H3: 2,6                                  # 19 pairs
* PAIR F1: 1,7 BLK 2
E1: 1,7,6                                # reduction candidate for 1,7
E1: 1,7 => CTR
* 92.3..658..6428.9.83.569.4....2...8.7.9..5.2..82..6.34..86.2.1.6.1.534722.37..869
E3: 1,7,2,9                              # reduction candidate for 1,7
E3: 1,7 => CTR
* 92.36...8516428.9.83.5.9...3.52..9817.9185...1829367544786923156.18534722537..869
F3: 1,7,2,9                              # reduction candidate for 1,7
F3: 1,7                                  # 28 pairs
* RESTART
* PAIR F1: 1,7 BLK 2
F3: 1,7,2,9                              # reduction candidate for 1,7
F3: 1,7                                  # 28 pairs
F3: 2,9                                  # 22 pairs
* PAIR F1: 1,7 ROW 1
G1: 1,7,5                                # reduction candidate for 1,7
G1: 1,7 => SOLVED
* 924361758156478293837592641613247985749185326582936174498623517371859462265714839
* DURATION: 0:00:20.842279  START: 01:10:46.818064  END: 01:11:07.660343 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-092-base-pr-001.dot
* REASONING
* DIS # A4: 1,5 => CTR => A4: 3,4,6
* DIS A4: 3,4,6 # A6: 3 => CTR => A6: 1,5
* DIS A4: 3,4,6 + A6: 1,5 # B6: 1,5 => CTR => B6: 8
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 # E1: 1,7 => CTR => E1: 6
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 # E3: 1,7 => CTR => E3: 2,9
* PRF A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # G1: 1,7 => SOL
* STA A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 + G1: 1,7
* CNT   6 HDP CHAINS /  20 HYP OPENED

Header Info

Top 95 Sudokus 092
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 924361758156478293837592641613247985749185326582936174498623517371859462265714839 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 # H1: 4,7 => UNS
* INC # H1: 5,6 => UNS
* DIS # A4: 1,5 => CTR => A4: 3,4,6
* INC # A4: 3,4,6 => UNS
* INC # A6: 1,5 => UNS
* INC # B4: 1,5 => UNS
* INC # B6: 1,5 => UNS
* INC # H3: 4,7 => UNS
* INC # H3: 2,6 => UNS
* INC # E1: 1,7 => UNS
* INC # E3: 1,7 => UNS
* INC # F3: 1,7 => UNS
* INC # G1: 1,7 => UNS
* INC # G1: 5,6 => UNS
* DIS # E3: 2,7 => CTR => E3: 1,6,9
* INC # E3: 1,6,9 => UNS
* INC # F3: 2,7 => UNS
* INC # G2: 2,7 => UNS
* INC # G2: 3 => UNS
* INC # G2: 3,7 => UNS
* INC # G2: 2 => UNS
* INC # I4: 3,7 => UNS
* INC # I7: 3,7 => UNS
* INC # A4: 3,5 => UNS
* INC # A6: 3,5 => UNS
* DIS # G4: 3,5 => CTR => G4: 1,6,7,9
* INC # G4: 1,6,7,9 => UNS
* INC # I4: 3,5 => UNS
* INC # D6: 1,8 => UNS
* INC # D6: 9 => UNS
* INC # B5: 1,8 => UNS
* INC # B5: 4,6 => UNS
* DIS # A7: 3,5 => CTR => A7: 4,6
* INC # A7: 4,6 => UNS
* INC # A8: 3,5 => UNS
* DIS # E9: 3,5 => CTR => E9: 1,4
* INC # E9: 1,4 => UNS
* INC # H9: 3,5 => UNS
* INC # D8: 6,9 => UNS
* INC # D8: 8 => UNS
* INC # E7: 3,9 => UNS
* PRF # F7: 3,9 => SOL
* INC # F7: 2,4 => UNS
* INC # E8: 3,9 => UNS
* INC # F4: 3,9 => UNS
* INC # F4: 4,7 => UNS
* CNT  46 HDP CHAINS /  46 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # H1: 4,7 => UNS
* INC # H1: 5,6 => UNS
* DIS # A4: 1,5 => CTR => A4: 3,4,6
* INC A4: 3,4,6 # A6: 1,5 => UNS
* INC A4: 3,4,6 # A6: 1,5 => UNS
* DIS A4: 3,4,6 # A6: 3 => CTR => A6: 1,5
* INC A4: 3,4,6 + A6: 1,5 # B4: 1,5 => UNS
* DIS A4: 3,4,6 + A6: 1,5 # B6: 1,5 => CTR => B6: 8
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # B4: 1,5 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # B4: 4,6 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # B4: 1,5 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # B4: 4,6 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # H3: 4,7 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 # H3: 2,6 => UNS
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 # E1: 1,7 => CTR => E1: 6
* DIS A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 # E3: 1,7 => CTR => E3: 2,9
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # F3: 1,7 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # F3: 1,7 => UNS
* INC A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # F3: 2,9 => UNS
* PRF A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 # G1: 1,7 => SOL
* STA A4: 3,4,6 + A6: 1,5 + B6: 8 + E1: 6 + E3: 2,9 + G1: 1,7
* CNT  20 HDP CHAINS /  20 HYP OPENED