Analysis of xx-top500-458-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 5....27...1.4..............26....8.....13........4.......6...31..9....4.7........ initial

Autosolve

position: 5...127...1.4..3........1..264...813...13.4.....24.......6...31..9....477........ autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A2: 8,9 => CTR => A2: 6
* PRF # A2: 6 => SOL
* DIS # A3: 8,9 => CTR => A3: 3,4,6
* DIS # B7: 4,8 => CTR => B7: 2,5
* PRF # A3: 4,8 => SOL
* DIS # A3: 3,6,9 => CTR => A3: 4,8
* CNT   6 HDP CHAINS /  10 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 # A2: 8,9 => CTR => A2: 6
* PRF A2: 6 => SOL
* STA A2: 6
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

5....27...1.4..............26....8.....13........4.......6...31..9....4.7........ initial
5...127...1.4..3........1..264...813...13.4.....24.......6...31..9....477........ autosolve
583912764612487359497563128264759813958136472371248596825674931139825647746391285 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
A5: 8,9
A6: 1,3
C6: 1,3
F5: 6,8
F6: 6,8
A7: 4,8
A8: 1,6
C9: 1,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A6,C6: 1.. / A6 = 1  =>  0 pairs (X) / C6 = 1  =>  0 pairs (_)
A8,C9: 1.. / A8 = 1  =>  0 pairs (*) / C9 = 1  =>  0 pairs (X)
F8,F9: 1.. / F8 = 1  =>  0 pairs (X) / F9 = 1  =>  0 pairs (_)
A8,F8: 1.. / A8 = 1  =>  0 pairs (*) / F8 = 1  =>  0 pairs (X)
C9,F9: 1.. / C9 = 1  =>  0 pairs (X) / F9 = 1  =>  0 pairs (_)
A6,A8: 1.. / A6 = 1  =>  0 pairs (X) / A8 = 1  =>  0 pairs (_)
C6,C9: 1.. / C6 = 1  =>  0 pairs (*) / C9 = 1  =>  0 pairs (X)
H5,I5: 2.. / H5 = 2  =>  8 pairs (_) / I5 = 2  =>  8 pairs (_)
A6,C6: 3.. / A6 = 3  =>  0 pairs (*) / C6 = 3  =>  0 pairs (X)
B8,B9: 3.. / B8 = 3  => 10 pairs (_) / B9 = 3  =>  0 pairs (X)
C1,D1: 3.. / C1 = 3  =>  0 pairs (*) / D1 = 3  =>  0 pairs (X)
A3,A6: 3.. / A3 = 3  =>  0 pairs (X) / A6 = 3  =>  0 pairs (_)
I1,I3: 4.. / I1 = 4  =>  9 pairs (_) / I3 = 4  =>  0 pairs (X)
F7,F9: 4.. / F7 = 4  =>  0 pairs (*) / F9 = 4  =>  0 pairs (X)
B1,I1: 4.. / B1 = 4  =>  0 pairs (X) / I1 = 4  =>  9 pairs (_)
B9,F9: 4.. / B9 = 4  =>  0 pairs (*) / F9 = 4  =>  0 pairs (X)
A3,A7: 4.. / A3 = 4  =>  0 pairs (*) / A7 = 4  =>  0 pairs (X)
C5,C7: 5.. / C5 = 5  =>  9 pairs (_) / C7 = 5  => 10 pairs (_)
E2,E3: 6.. / E2 = 6  =>  0 pairs (X) / E3 = 6  =>  8 pairs (_)
F5,F6: 6.. / F5 = 6  =>  6 pairs (_) / F6 = 6  => 13 pairs (_)
A8,C9: 6.. / A8 = 6  =>  0 pairs (X) / C9 = 6  =>  0 pairs (_)
A8,G8: 6.. / A8 = 6  =>  0 pairs (X) / G8 = 6  =>  0 pairs (_)
H5,H6: 7.. / H5 = 7  =>  7 pairs (_) / H6 = 7  =>  8 pairs (_)
E7,F7: 7.. / E7 = 7  =>  9 pairs (_) / F7 = 7  =>  0 pairs (X)
B6,H6: 7.. / B6 = 7  =>  7 pairs (_) / H6 = 7  =>  8 pairs (_)
D3,D4: 7.. / D3 = 7  => 11 pairs (_) / D4 = 7  => 10 pairs (_)
F5,F6: 8.. / F5 = 8  => 13 pairs (_) / F6 = 8  =>  6 pairs (_)
H9,I9: 8.. / H9 = 8  =>  9 pairs (_) / I9 = 8  =>  8 pairs (_)
B6,F6: 8.. / B6 = 8  => 13 pairs (_) / F6 = 8  =>  6 pairs (_)
* DURATION: 0:00:53.386295  START: 18:24:24.458033  END: 18:25:17.844328 2017-05-04
* CP COUNT: (29)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,A7,A8,C6,C9,F5,F6)
* 5...127...1.4..3........1..264...813...13.4.....24.......6...31..9....477........
* PAIR A5: 8,9 BLK 4
B5: 8,9,5,7                              # reduction candidate for 8,9
B5: 8,9                                  # 10 pairs
B6: 8,9,5,7                              # reduction candidate for 8,9
B6: 8,9                                  # 11 pairs
* PAIR A5: 8,9 COL A
A2: 8,9,6                                # reduction candidate for 8,9
A2: 8,9 => CTR
* 5...127...1.4..3.......31..264...813...13.4.....24....4..6...31..9..1.477.1..4...
A2: 6 => SOLVED
* 583912764612487359497563128264759813958136472371248596825674931139825647746391285
A3: 8,9,3,4,6                            # reduction candidate for 8,9
A3: 8,9 => CTR
* 5...127...1.4..3........1..264...813...13.4..3.124....4..6...311.9...6477.6......
A3: 3,4,6                                #  8 pairs
* PAIR A7: 4,8 BLK 7
B7: 4,8,2,5                              # reduction candidate for 4,8
B7: 4,8 => CTR
* 5...127...1.4..3.......31..264...813...13.4..3.124.......6...311.9....477........
B7: 2,5                                  #  9 pairs
* PAIR A7: 4,8 COL A
A3: 4,8,3,6,9                            # reduction candidate for 4,8
A3: 4,8 => SOLVED
* 583912764612487359497563128264759813958136472371248596825674931139825647746391285
A3: 3,6,9 => CTR
* 5...127...1.4..3.......31..264...813...13.4.....24....4..6...31..9..1.477.1..4...
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-458-base-pr-000.dot
* REASONING
* DIS # A2: 8,9 => CTR => A2: 6
* PRF # A2: 6 => SOL
* DIS # A3: 8,9 => CTR => A3: 3,4,6
* DIS # B7: 4,8 => CTR => B7: 2,5
* PRF # A3: 4,8 => SOL
* DIS # A3: 3,6,9 => CTR => A3: 4,8
* CNT   6 HDP CHAINS /  10 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,A7,A8,C6,C9,F5,F6)
* 5...127...1.4..3........1..264...813...13.4.....24.......6...31..9....477........
* PAIR A5: 8,9 BLK 4
B5: 8,9,5,7                              # reduction candidate for 8,9
B5: 8,9                                  # 10 pairs
B6: 8,9,5,7                              # reduction candidate for 8,9
B6: 8,9                                  # 11 pairs
* PAIR A5: 8,9 COL A
A2: 8,9,6                                # reduction candidate for 8,9
A2: 8,9 => CTR
* 5...127...1.4..3.......31..264...813...13.4.....24....4..6...31..9..1.477.1..4...
A2: 6 => SOLVED
* 583912764612487359497563128264759813958136472371248596825674931139825647746391285
* DURATION: 0:00:03.815404  START: 18:25:29.226460  END: 18:25:33.041864 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-458-base-pr-001.dot
* REASONING
* DIS # A2: 8,9 => CTR => A2: 6
* PRF A2: 6 => SOL
* STA A2: 6
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 458

solution: 583912764612487359497563128264759813958136472371248596825674931139825647746391285
info: 95523    FNBHYK   S8.f     44295

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

Solution

position: 583912764612487359497563128264759813958136472371248596825674931139825647746391285 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 # B5: 8,9 => UNS
* INC # B6: 8,9 => UNS
* DIS # A2: 8,9 => CTR => A2: 6
* PRF # A2: 6 => SOL
* DIS # A3: 8,9 => CTR => A3: 3,4,6
* INC # A3: 3,4,6 => UNS
* DIS # B7: 4,8 => CTR => B7: 2,5
* INC # B7: 2,5 => UNS
* PRF # A3: 4,8 => SOL
* DIS # A3: 3,6,9 => CTR => A3: 4,8
* CNT  10 HDP CHAINS /  10 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B5: 8,9 => UNS
* INC # B6: 8,9 => UNS
* DIS # A2: 8,9 => CTR => A2: 6
* PRF A2: 6 => SOL
* STA A2: 6
* CNT   4 HDP CHAINS /   3 HYP OPENED