Analysis of xx-top500-421-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 38......2...1...........4....7..65......8..1.....2.......5..73.24.......8........ initial

Autosolve

position: 38......2..21..8.....2.84...27..6589.3..8.21...8.2.34....5427382438.....875....24 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I3: 1 => CTR => I3: 3,5
* DIS # E2: 3,5 => CTR => E2: 6,7,9
* PRF # E9: 1,3 => SOL
* DIS # F5: 7,9 => CTR => F5: 4,5
* DIS # F6: 7,9 => CTR => F6: 1,5
* DIS # D1: 7,9 => CTR => D1: 4,6
* DIS # I3: 1,5 => CTR => I3: 3
* CNT   7 HDP CHAINS /  15 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 # I3: 1 => CTR => I3: 3,5
* PRF I3: 3,5 # E9: 1,3 => SOL
* STA I3: 3,5 + E9: 1,3
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

38......2...1...........4....7..65......8..1.....2.......5..73.24.......8........ initial
38......2..21..8.....2.84...27..6589.3..8.21...8.2.34....5427382438.....875....24 autosolve
389654172462173895751298463127436589634985217598721346916542738243867951875319624 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
I2: 3,5
A4: 1,4
D4: 3,4
E4: 1,3
D6: 7,9
I5: 6,7
I6: 6,7
I8: 1,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G1,I3: 1.. / G1 = 1  => 11 pairs (_) / I3 = 1  =>  0 pairs (X)
E4,F6: 1.. / E4 = 1  =>  0 pairs (X) / F6 = 1  =>  0 pairs (_)
C1,G1: 1.. / C1 = 1  =>  0 pairs (X) / G1 = 1  => 11 pairs (_)
A4,E4: 1.. / A4 = 1  =>  0 pairs (*) / E4 = 1  =>  0 pairs (X)
I3,I8: 1.. / I3 = 1  =>  0 pairs (X) / I8 = 1  => 11 pairs (_)
I2,I3: 3.. / I2 = 3  =>  0 pairs (X) / I3 = 3  => 10 pairs (_)
D4,E4: 3.. / D4 = 3  =>  0 pairs (X) / E4 = 3  =>  0 pairs (_)
E3,I3: 3.. / E3 = 3  =>  0 pairs (X) / I3 = 3  => 10 pairs (_)
D4,D9: 3.. / D4 = 3  =>  0 pairs (X) / D9 = 3  =>  0 pairs (_)
F2,F9: 3.. / F2 = 3  =>  0 pairs (*) / F9 = 3  =>  0 pairs (X)
C1,A2: 4.. / C1 = 4  =>  0 pairs (X) / A2 = 4  =>  0 pairs (_)
A2,F2: 4.. / A2 = 4  =>  0 pairs (*) / F2 = 4  =>  0 pairs (X)
A4,D4: 4.. / A4 = 4  =>  0 pairs (X) / D4 = 4  =>  0 pairs (_)
C1,C5: 4.. / C1 = 4  =>  0 pairs (X) / C5 = 4  =>  0 pairs (_)
F5,F6: 5.. / F5 = 5  =>  8 pairs (_) / F6 = 5  =>  0 pairs (X)
H8,I8: 5.. / H8 = 5  => 11 pairs (_) / I8 = 5  =>  0 pairs (X)
E1,H1: 5.. / E1 = 5  =>  8 pairs (_) / H1 = 5  =>  0 pairs (X)
A5,F5: 5.. / A5 = 5  =>  0 pairs (X) / F5 = 5  =>  8 pairs (_)
I5,I6: 6.. / I5 = 6  =>  9 pairs (_) / I6 = 6  =>  7 pairs (_)
D1,D9: 6.. / D1 = 6  => 12 pairs (_) / D9 = 6  =>  0 pairs (X)
A2,A3: 7.. / A2 = 7  =>  0 pairs (X) / A3 = 7  =>  8 pairs (_)
I5,I6: 7.. / I5 = 7  =>  7 pairs (_) / I6 = 7  =>  9 pairs (_)
E8,F8: 7.. / E8 = 7  => 10 pairs (_) / F8 = 7  => 11 pairs (_)
* DURATION: 0:00:37.097644  START: 17:12:23.736898  END: 17:13:00.834542 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,D4,D6,E4,I2,I5,I6,I8)
* 38......2..21..8.....2.84...27..6589.3..8.21...8.2.34....5427382438.....875....24
* PAIR I2: 3,5 BLK 3
I3: 3,5,1                                # reduction candidate for 3,5
I3: 1 => CTR
* 381.....24.21..8.3...2384.1.27316589.3..8.21...8.2.34....5427382438....5875..3124
I3: 3,5                                  # 11 pairs
* PAIR I2: 3,5 ROW 2
E2: 3,5,6,7,9                            # reduction candidate for 3,5
E2: 3,5 => CTR
* 381.....24.21..8.....2.84...27316589.3..8.21...8.2.34....5427382438.1..5875..3124
E2: 6,7,9                                #  8 pairs
* PAIR E4: 1,3 COL E
E9: 1,3,6,9                              # reduction candidate for 1,3
E9: 1,3 => SOLVED
* 389654172462173895751298463127436589634985217598721346916542738243867951875319624
E9: 6,9                                  #  9 pairs
* PAIR D6: 7,9 BLK 5
D5: 7,9,4                                # reduction candidate for 7,9
D5: 7,9                                  # 13 pairs
F5: 7,9,4,5                              # reduction candidate for 7,9
F5: 7,9 => CTR
* 384...1.2..21.48.....2.84..42731658953.48.21...8.2534....5427382438....1875....24
F5: 4,5                                  #  9 pairs
F6: 7,9,1,5                              # reduction candidate for 7,9
F6: 7,9 => CTR
* 384...1.2..21.48.....2.84..427316589.3.485217..8.2.346...5427382438....1875....24
F6: 1,5                                  #  9 pairs
* PAIR D6: 7,9 COL D
D1: 7,9,4,6                              # reduction candidate for 7,9
D1: 7,9 => CTR
* 384...1.2..21.48.....2.84..427316589.3.48.21...8.2.34....5427382438..6.18756...24
D1: 4,6                                  #  9 pairs
* PAIR I8: 1,5 COL I
I3: 1,5,3                                # reduction candidate for 1,5
I3: 1,5 => CTR
* 381.....24.21..8.3...2384...27316589.3..8.21...8.2.34....5427382438.....875..3124
I3: 3                                    # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-421-base-pr-000.dot
* REASONING
* DIS # I3: 1 => CTR => I3: 3,5
* DIS # E2: 3,5 => CTR => E2: 6,7,9
* PRF # E9: 1,3 => SOL
* DIS # F5: 7,9 => CTR => F5: 4,5
* DIS # F6: 7,9 => CTR => F6: 1,5
* DIS # D1: 7,9 => CTR => D1: 4,6
* DIS # I3: 1,5 => CTR => I3: 3
* CNT   7 HDP CHAINS /  15 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,D4,D6,E4,I2,I5,I6,I8)
* 38......2..21..8.....2.84...27..6589.3..8.21...8.2.34....5427382438.....875....24
* PAIR I2: 3,5 BLK 3
I3: 3,5,1                                # reduction candidate for 3,5
I3: 1 => CTR
* 381.....24.21..8.3...2384.1.27316589.3..8.21...8.2.34....5427382438....5875..3124
* PAIR E4: 1,3 COL E
E9: 1,3,6,9                              # reduction candidate for 1,3
E9: 1,3 => SOLVED
* 389654172462173895751298463127436589634985217598721346916542738243867951875319624
* DURATION: 0:00:04.205780  START: 17:13:13.678362  END: 17:13:17.884142 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-421-base-pr-001.dot
* REASONING
* DIS # I3: 1 => CTR => I3: 3,5
* PRF I3: 3,5 # E9: 1,3 => SOL
* STA I3: 3,5 + E9: 1,3
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 421

solution: 389654172462173895751298463127436589634985217598721346916542738243867951875319624
info: 95113    FNBXYK   S8.f     48374

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

Solution

position: 389654172462173895751298463127436589634985217598721346916542738243867951875319624 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 # I3: 3,5 => UNS
* DIS # I3: 1 => CTR => I3: 3,5
* DIS # E2: 3,5 => CTR => E2: 6,7,9
* INC # E2: 6,7,9 => UNS
* PRF # E9: 1,3 => SOL
* INC # E9: 6,9 => UNS
* INC # D5: 7,9 => UNS
* DIS # F5: 7,9 => CTR => F5: 4,5
* INC # F5: 4,5 => UNS
* DIS # F6: 7,9 => CTR => F6: 1,5
* INC # F6: 1,5 => UNS
* DIS # D1: 7,9 => CTR => D1: 4,6
* INC # D1: 4,6 => UNS
* DIS # I3: 1,5 => CTR => I3: 3
* INC # I3: 3 => UNS
* CNT  15 HDP CHAINS /  15 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # I3: 3,5 => UNS
* DIS # I3: 1 => CTR => I3: 3,5
* PRF I3: 3,5 # E9: 1,3 => SOL
* STA I3: 3,5 + E9: 1,3
* CNT   3 HDP CHAINS /   3 HYP OPENED