Analysis of xx-top500-023-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....5..6.4.2...........1......3..2.4.18............7...5..6..1.7..2..4........... initial

Autosolve

position: 1..457.624.2...175....21.4....31.2.4.187426...245..7.125..64.177.12.54.6.4617.52. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B1: 3,9 => CTR => B1: 8
* PRF # B1: 8 => SOL
* PRF # B3: 3,9 => SOL
* PRF # G1: 3,9 => SOL
* DIS # G1: 8 => CTR => G1: 3,9
* DIS # E2: 8,9 => CTR => E2: 3
* DIS # I3: 3,9 => CTR => I3: 8
* PRF # I3: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # F9: 8,9 => CTR => F9: 3
* PRF # A3: 5,6 => SOL
* DIS # F9: 8,9 => CTR => F9: 3
* DIS # G7: 3 => CTR => G7: 8,9
* DIS # D3: 8,9 => CTR => D3: 6
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # E8: 3,9 => CTR => E8: 8
* PRF # E8: 8 => SOL
* CNT  28 HDP CHAINS /  50 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 # B1: 3,9 => CTR => B1: 8
* PRF B1: 8 => SOL
* STA B1: 8
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

....5..6.4.2...........1......3..2.4.18............7...5..6..1.7..2..4........... initial
1..457.624.2...175....21.4....31.2.4.187426...245..7.125..64.177.12.54.6.4617.52. autosolve
189457362462839175537621948675318294918742653324596781253964817791285436846173529 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
C1: 3,9
C3: 5,7
C4: 5,7
E6: 8,9
I5: 3,9
C7: 3,9
A9: 8,9
D7: 8,9
H8: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,F2: 3.. / E2 = 3  => 12 pairs (_) / F2 = 3  =>  0 pairs (X)
A5,A6: 3.. / A5 = 3  => 14 pairs (_) / A6 = 3  => 12 pairs (_)
C7,B8: 3.. / C7 = 3  => 14 pairs (_) / B8 = 3  =>  0 pairs (X)
E8,F9: 3.. / E8 = 3  =>  0 pairs (X) / F9 = 3  => 12 pairs (_)
A6,H6: 3.. / A6 = 3  => 12 pairs (_) / H6 = 3  => 14 pairs (_)
C7,G7: 3.. / C7 = 3  => 14 pairs (_) / G7 = 3  =>  0 pairs (X)
F9,I9: 3.. / F9 = 3  => 12 pairs (_) / I9 = 3  =>  0 pairs (X)
C1,C7: 3.. / C1 = 3  =>  0 pairs (X) / C7 = 3  => 14 pairs (_)
E2,E8: 3.. / E2 = 3  => 12 pairs (_) / E8 = 3  =>  0 pairs (X)
F2,F9: 3.. / F2 = 3  =>  0 pairs (X) / F9 = 3  => 12 pairs (_)
A3,C3: 5.. / A3 = 5  =>  0 pairs (*) / C3 = 5  =>  0 pairs (X)
H4,H5: 5.. / H4 = 5  => 14 pairs (_) / H5 = 5  => 11 pairs (_)
A5,H5: 5.. / A5 = 5  => 14 pairs (_) / H5 = 5  => 11 pairs (_)
C3,C4: 5.. / C3 = 5  =>  9 pairs (_) / C4 = 5  =>  0 pairs (*)
D2,D3: 6.. / D2 = 6  =>  0 pairs (X) / D3 = 6  => 11 pairs (_)
F4,F6: 6.. / F4 = 6  => 15 pairs (_) / F6 = 6  => 11 pairs (_)
B2,D2: 6.. / B2 = 6  => 11 pairs (_) / D2 = 6  =>  0 pairs (X)
A6,F6: 6.. / A6 = 6  => 15 pairs (_) / F6 = 6  => 11 pairs (_)
B3,C3: 7.. / B3 = 7  =>  9 pairs (_) / C3 = 7  =>  0 pairs (*)
B4,C4: 7.. / B4 = 7  =>  0 pairs (*) / C4 = 7  =>  0 pairs (X)
B3,B4: 7.. / B3 = 7  =>  9 pairs (_) / B4 = 7  =>  0 pairs (*)
C3,C4: 7.. / C3 = 7  =>  0 pairs (*) / C4 = 7  =>  0 pairs (X)
H4,H6: 8.. / H4 = 8  => 12 pairs (_) / H6 = 8  => 14 pairs (_)
B8,A9: 8.. / B8 = 8  =>  0 pairs (X) / A9 = 8  =>  0 pairs (_)
G7,I9: 8.. / G7 = 8  =>  0 pairs (*) / I9 = 8  =>  0 pairs (X)
B1,G1: 8.. / B1 = 8  =>  0 pairs (*) / G1 = 8  =>  0 pairs (X)
F4,H4: 8.. / F4 = 8  => 14 pairs (_) / H4 = 8  => 12 pairs (_)
D7,G7: 8.. / D7 = 8  =>  0 pairs (X) / G7 = 8  =>  0 pairs (_)
B8,E8: 8.. / B8 = 8  =>  0 pairs (X) / E8 = 8  =>  0 pairs (_)
A3,A9: 8.. / A3 = 8  =>  0 pairs (X) / A9 = 8  =>  0 pairs (_)
I3,I9: 8.. / I3 = 8  =>  0 pairs (*) / I9 = 8  =>  0 pairs (X)
C1,C7: 9.. / C1 = 9  => 14 pairs (_) / C7 = 9  =>  0 pairs (X)
* DURATION: 0:00:59.427146  START: 03:22:11.218350  END: 03:23:10.645496 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,C1,C3,C4,C7,D7,E6,H8,I5)
* 1..457.624.2...175....21.4....31.2.4.187426...245..7.125..64.177.12.54.6.4617.52.
* PAIR C1: 3,9 BLK 1
B1: 3,9,8                                # reduction candidate for 3,9
B1: 3,9 => CTR
* 1.94578624629381758.5621.4..97316284.1874265962458973125.864.177812.54.6946173528
B1: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
B3: 3,9,6,7,8                            # reduction candidate for 3,9
B3: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
B3: 6,7,8                                # 10 pairs
* PAIR C1: 3,9 ROW 1
G1: 3,9,8                                # reduction candidate for 3,9
G1: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
G1: 8 => CTR
* 1.94578624629381758.5621.4..97316284.1874265962458973125.864.177812.54.6946173528
* PAIR E6: 8,9 BLK 5
F4: 8,9,6                                # reduction candidate for 8,9
F4: 8,9                                  # 11 pairs
F6: 8,9,6                                # reduction candidate for 8,9
F6: 8,9                                  # 15 pairs
* PAIR E6: 8,9 ROW 6
H6: 8,9,3                                # reduction candidate for 8,9
H6: 3                                    # 14 pairs
H6: 8,9                                  # 12 pairs
* PAIR E6: 8,9 COL E
E2: 8,9,3                                # reduction candidate for 8,9
E2: 8,9 => CTR
* 1..457.624.2..3175....21.48...31.2.4.187426.9.245..7.1253964817781235496.4617.523
E2: 3                                    # 12 pairs
E8: 8,9,3                                # reduction candidate for 8,9
E8: 8,9                                  # 12 pairs
* PAIR I5: 3,9 BLK 6
H5: 3,9,5                                # reduction candidate for 3,9
H5: 3,9                                  # 14 pairs
H6: 3,9,8                                # reduction candidate for 3,9
H6: 3,9                                  # 12 pairs
* PAIR I5: 3,9 ROW 5
A5: 3,9,5                                # reduction candidate for 3,9
A5: 5                                    # 14 pairs
A5: 3,9                                  # 11 pairs
* PAIR I5: 3,9 COL I
I3: 3,9,8                                # reduction candidate for 3,9
I3: 3,9 => CTR
* 1.9457862462938175875621.4..97316284.1874265962458973125.864.177812.54.6946173528
I3: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
I9: 3,9,8                                # reduction candidate for 3,9
I9: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
I9: 8 => CTR
* 1.9457862462938175875621349.97316284.187426...245..7.125.864.17781295436946173528
* PAIR C7: 3,9 BLK 7
B8: 3,9,8                                # reduction candidate for 3,9
B8: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
B8: 8 => CTR
* 1.9457862462...1758.5621349.9731.2.4.187426933245.67812538649177812954.694617.52.
* PAIR C7: 3,9 ROW 7
G7: 3,9,8                                # reduction candidate for 3,9
G7: 3,9 => CTR
* 1.94578624629381758.5621.4..97316284.1874265962458973125.864.177812.54.6946173528
G7: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
* PAIR A9: 8,9 BLK 7
B8: 8,9,3                                # reduction candidate for 8,9
B8: 3 => CTR
* 1..457.624.2...175....21.4....31.2.4.187426...245..7.125..64.17731285496.4617.52.
B8: 8,9                                  # 14 pairs
* PAIR A9: 8,9 ROW 9
F9: 8,9,3                                # reduction candidate for 8,9
F9: 8,9 => CTR
* 1..457.624.2..3175....21.48...31.2.4.187426.9.245..7.1253964817781235496.4617.523
F9: 3                                    # 12 pairs
I9: 8,9,3                                # reduction candidate for 8,9
I9: 8,9                                  # 12 pairs
* PAIR A9: 8,9 COL A
A3: 8,9,5,6                              # reduction candidate for 8,9
A3: 5,6 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
A3: 8,9                                  # 18 pairs
* PAIR D7: 8,9 BLK 8
E8: 8,9,3                                # reduction candidate for 8,9
E8: 8,9                                  # 12 pairs
F9: 8,9,3                                # reduction candidate for 8,9
F9: 8,9 => CTR
* 1..457.624.2..3175....21.48...31.2.4.187426.9.245..7.1253964817781235496.4617.523
F9: 3                                    # 12 pairs
* PAIR D7: 8,9 ROW 7
G7: 8,9,3                                # reduction candidate for 8,9
G7: 3 => CTR
* 1..457.624.2...175....21.4....31.2.4.187426...245..7.125.8643177.12.54.6.4617.52.
G7: 8,9                                  # 14 pairs
* PAIR D7: 8,9 COL D
D2: 8,9,6                                # reduction candidate for 8,9
D2: 8,9                                  # 11 pairs
D3: 8,9,6                                # reduction candidate for 8,9
D3: 8,9 => CTR
* 1..457.624.26..175....21.48...31.2.4.187426...245..7.125.864.177.12.54.684617.52.
D3: 6                                    # 11 pairs
* PAIR H8: 3,9 BLK 9
G7: 3,9,8                                # reduction candidate for 3,9
G7: 3,9 => CTR
* 1.94578624629381758.5621.4..97316284.1874265962458973125.864.177812.54.6946173528
G7: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
I9: 3,9,8                                # reduction candidate for 3,9
I9: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
I9: 8 => CTR
* 1.9457862462938175875621349.97316284.187426...245..7.125.864.17781295436946173528
* PAIR H8: 3,9 ROW 8
B8: 3,9,8                                # reduction candidate for 3,9
B8: 3,9 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
B8: 8 => CTR
* 1.9457862462...1758.5621349.9731.2.4.187426933245.67812538649177812954.694617.52.
E8: 3,9,8                                # reduction candidate for 3,9
E8: 3,9 => CTR
* 139457862462938175875621349.97316284.187426...245..7.1253864917781295436946173528
E8: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
* PAIR H8: 3,9 COL H
H5: 3,9,5                                # reduction candidate for 3,9
H5: 3,9                                  # 14 pairs
H6: 3,9,8                                # reduction candidate for 3,9
H6: 3,9                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-023-base-pr-000.dot
* REASONING
* DIS # B1: 3,9 => CTR => B1: 8
* PRF # B1: 8 => SOL
* PRF # B3: 3,9 => SOL
* PRF # G1: 3,9 => SOL
* DIS # G1: 8 => CTR => G1: 3,9
* DIS # E2: 8,9 => CTR => E2: 3
* DIS # I3: 3,9 => CTR => I3: 8
* PRF # I3: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # F9: 8,9 => CTR => F9: 3
* PRF # A3: 5,6 => SOL
* DIS # F9: 8,9 => CTR => F9: 3
* DIS # G7: 3 => CTR => G7: 8,9
* DIS # D3: 8,9 => CTR => D3: 6
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # E8: 3,9 => CTR => E8: 8
* PRF # E8: 8 => SOL
* CNT  28 HDP CHAINS /  50 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,C1,C3,C4,C7,D7,E6,H8,I5)
* 1..457.624.2...175....21.4....31.2.4.187426...245..7.125..64.177.12.54.6.4617.52.
* PAIR C1: 3,9 BLK 1
B1: 3,9,8                                # reduction candidate for 3,9
B1: 3,9 => CTR
* 1.94578624629381758.5621.4..97316284.1874265962458973125.864.177812.54.6946173528
B1: 8 => SOLVED
* 189457362462839175537621948675318294918742653324596781253964817791285436846173529
* DURATION: 0:00:02.011698  START: 03:24:07.030359  END: 03:24:09.042057 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-023-base-pr-001.dot
* REASONING
* DIS # B1: 3,9 => CTR => B1: 8
* PRF B1: 8 => SOL
* STA B1: 8
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 023

solution: 189457362462839175537621948675318294918742653324596781253964817791285436846173529
info: 1319     FNBTWXY  S8.f     4755

http://www.sfsudoku.com/su17ExtremeDiff500.txt from http://www.minimumsudoku.com/

Solution

position: 189457362462839175537621948675318294918742653324596781253964817791285436846173529 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 # B1: 3,9 => CTR => B1: 8
* PRF # B1: 8 => SOL
* PRF # B3: 3,9 => SOL
* INC # B3: 6,7,8 => UNS
* PRF # G1: 3,9 => SOL
* DIS # G1: 8 => CTR => G1: 3,9
* INC # F4: 8,9 => UNS
* INC # F6: 8,9 => UNS
* INC # H6: 8,9 => UNS
* INC # H6: 3 => UNS
* DIS # E2: 8,9 => CTR => E2: 3
* INC # E2: 3 => UNS
* INC # E8: 8,9 => UNS
* INC # H5: 3,9 => UNS
* INC # H6: 3,9 => UNS
* INC # A5: 3,9 => UNS
* INC # A5: 5 => UNS
* DIS # I3: 3,9 => CTR => I3: 8
* PRF # I3: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* INC # B8: 8,9 => UNS
* DIS # B8: 3 => CTR => B8: 8,9
* DIS # F9: 8,9 => CTR => F9: 3
* INC # F9: 3 => UNS
* INC # I9: 8,9 => UNS
* INC # A3: 8,9 => UNS
* PRF # A3: 5,6 => SOL
* INC # E8: 8,9 => UNS
* DIS # F9: 8,9 => CTR => F9: 3
* INC # F9: 3 => UNS
* INC # G7: 8,9 => UNS
* DIS # G7: 3 => CTR => G7: 8,9
* INC # D2: 8,9 => UNS
* DIS # D3: 8,9 => CTR => D3: 6
* INC # D3: 6 => UNS
* DIS # G7: 3,9 => CTR => G7: 8
* PRF # G7: 8 => SOL
* PRF # I9: 3,9 => SOL
* DIS # I9: 8 => CTR => I9: 3,9
* PRF # B8: 3,9 => SOL
* DIS # B8: 8 => CTR => B8: 3,9
* DIS # E8: 3,9 => CTR => E8: 8
* PRF # E8: 8 => SOL
* INC # H5: 3,9 => UNS
* INC # H6: 3,9 => UNS
* CNT  50 HDP CHAINS /  50 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B1: 3,9 => CTR => B1: 8
* PRF B1: 8 => SOL
* STA B1: 8
* CNT   2 HDP CHAINS /   1 HYP OPENED