Analysis of xx-top500-249-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..2.63.........4.1..........3....56.4..8..................2.63.17.4.....8........ initial

Autosolve

position: .42163..536..8.4.1.81...3.623891.56.4..8.62.36..3.2..9..4721638176438952823695... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A3: 5 => CTR => A3: 7,9
* DIS # H1: 7,9 => CTR => H1: 8
* PRF # H1: 8 => SOL
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* DIS # C5: 7 => CTR => C5: 5,9
* PRF # F3: 7,9 => SOL
* DIS # F3: 4 => CTR => F3: 7,9
* DIS # H2: 2 => CTR => H2: 7,9
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* PRF # E6: 5 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 9 => CTR => H1: 7,8
* DIS # G6: 1 => CTR => G6: 7,8
* DIS # B5: 9 => CTR => B5: 1,5
* DIS # C5: 5,7 => CTR => C5: 9
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* PRF # E6: 5 => SOL
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* DIS # C5: 5,7 => CTR => C5: 9
* PRF # H6: 4,7 => SOL
* DIS # H6: 1,8 => CTR => H6: 4,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # H6: 1,7 => CTR => H6: 4,8
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* DIS # B5: 1 => CTR => B5: 5,9
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # H9: 1 => CTR => H9: 4,7
* CNT  40 HDP CHAINS /  52 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 # A3: 5 => CTR => A3: 7,9
* DIS A3: 7,9 # H1: 7,9 => CTR => H1: 8
* PRF A3: 7,9 + H1: 8 => SOL
* STA A3: 7,9 + H1: 8
* CNT   3 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

..2.63.........4.1..........3....56.4..8..................2.63.17.4.....8........ initial
.42163..536..8.4.1.81...3.623891.56.4..8.62.36..3.2..9..4721638176438952823695... autosolve
942163785365287491781549326238914567459876213617352849594721638176438952823695174 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
A1: 7,9
C2: 5,9
D2: 2,5
F2: 7,9
D3: 2,5
E3: 4,7
G1: 7,8
B6: 1,5
C6: 5,7
F4: 4,7
E5: 5,7
I4: 4,7
H5: 1,7
A7: 5,9
B7: 5,9
G9: 1,7
I9: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B5,B6: 1.. / B5 = 1  =>  0 pairs (X) / B6 = 1  => 17 pairs (_)
G9,H9: 1.. / G9 = 1  => 18 pairs (_) / H9 = 1  =>  0 pairs (X)
B5,H5: 1.. / B5 = 1  =>  0 pairs (X) / H5 = 1  => 17 pairs (_)
G6,G9: 1.. / G6 = 1  =>  0 pairs (X) / G9 = 1  => 18 pairs (_)
D2,D3: 2.. / D2 = 2  => 16 pairs (_) / D3 = 2  =>  0 pairs (X)
H2,H3: 2.. / H2 = 2  =>  0 pairs (X) / H3 = 2  => 16 pairs (_)
D2,H2: 2.. / D2 = 2  => 16 pairs (_) / H2 = 2  =>  0 pairs (X)
D3,H3: 2.. / D3 = 2  =>  0 pairs (X) / H3 = 2  => 16 pairs (_)
E3,F3: 4.. / E3 = 4  =>  0 pairs (*) / F3 = 4  =>  0 pairs (X)
F4,E6: 4.. / F4 = 4  =>  0 pairs (*) / E6 = 4  =>  0 pairs (X)
I4,H6: 4.. / I4 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
H9,I9: 4.. / H9 = 4  =>  0 pairs (X) / I9 = 4  =>  0 pairs (_)
F4,I4: 4.. / F4 = 4  =>  0 pairs (*) / I4 = 4  =>  0 pairs (X)
E6,H6: 4.. / E6 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
E3,E6: 4.. / E3 = 4  =>  0 pairs (*) / E6 = 4  =>  0 pairs (X)
F3,F4: 4.. / F3 = 4  =>  0 pairs (X) / F4 = 4  =>  0 pairs (_)
H6,H9: 4.. / H6 = 4  =>  0 pairs (*) / H9 = 4  =>  0 pairs (X)
I4,I9: 4.. / I4 = 4  =>  0 pairs (X) / I9 = 4  =>  0 pairs (_)
C2,A3: 5.. / C2 = 5  => 16 pairs (_) / A3 = 5  =>  0 pairs (X)
D2,D3: 5.. / D2 = 5  =>  0 pairs (X) / D3 = 5  => 16 pairs (_)
E5,E6: 5.. / E5 = 5  => 19 pairs (_) / E6 = 5  =>  0 pairs (*)
A7,B7: 5.. / A7 = 5  => 16 pairs (_) / B7 = 5  =>  0 pairs (X)
C2,D2: 5.. / C2 = 5  => 16 pairs (_) / D2 = 5  =>  0 pairs (X)
A3,D3: 5.. / A3 = 5  =>  0 pairs (X) / D3 = 5  => 16 pairs (_)
A3,A7: 5.. / A3 = 5  =>  0 pairs (X) / A7 = 5  => 16 pairs (_)
A1,A3: 7.. / A1 = 7  =>  0 pairs (X) / A3 = 7  =>  0 pairs (_)
C5,C6: 7.. / C5 = 7  =>  0 pairs (X) / C6 = 7  => 19 pairs (_)
F2,H2: 7.. / F2 = 7  =>  0 pairs (*) / H2 = 7  =>  0 pairs (X)
F4,I4: 7.. / F4 = 7  =>  0 pairs (X) / I4 = 7  =>  0 pairs (_)
I4,I9: 7.. / I4 = 7  =>  0 pairs (*) / I9 = 7  =>  0 pairs (X)
G1,H1: 8.. / G1 = 8  =>  0 pairs (X) / H1 = 8  =>  0 pairs (_)
G6,H6: 8.. / G6 = 8  =>  0 pairs (*) / H6 = 8  =>  0 pairs (X)
G1,G6: 8.. / G1 = 8  =>  0 pairs (X) / G6 = 8  =>  0 pairs (_)
H1,H6: 8.. / H1 = 8  =>  0 pairs (*) / H6 = 8  =>  0 pairs (X)
F2,F3: 9.. / F2 = 9  =>  0 pairs (X) / F3 = 9  =>  0 pairs (_)
B5,C5: 9.. / B5 = 9  =>  0 pairs (X) / C5 = 9  => 16 pairs (_)
A7,B7: 9.. / A7 = 9  =>  0 pairs (X) / B7 = 9  => 16 pairs (_)
A1,H1: 9.. / A1 = 9  =>  0 pairs (*) / H1 = 9  =>  0 pairs (X)
B5,B7: 9.. / B5 = 9  =>  0 pairs (X) / B7 = 9  => 16 pairs (_)
C2,C5: 9.. / C2 = 9  =>  0 pairs (X) / C5 = 9  => 16 pairs (_)
* DURATION: 0:01:08.692822  START: 11:17:43.896621  END: 11:18:52.589443 2017-05-04
* CP COUNT: (40)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A7,B6,B7,C2,C6,D2,D3,E3,E5,F2,F4,G1,G9,H5,I4,I9)
* .42163..536..8.4.1.81...3.623891.56.4..8.62.36..3.2..9..4721638176438952823695...
* PAIR A1: 7,9 BLK 1
A3: 7,9,5                                # reduction candidate for 7,9
A3: 5 => CTR
* 74216389536958742158124937623891.56.4..8.62.36..3.2..9..4721638176438952823695...
A3: 7,9                                  # 16 pairs
* PAIR A1: 7,9 ROW 1
H1: 7,9,8                                # reduction candidate for 7,9
H1: 7,9 => CTR
* .421638.536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
H1: 8 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR C2: 5,9 BLK 1
A3: 5,9,7                                # reduction candidate for 5,9
A3: 5,9 => CTR
* 74216389536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
A3: 7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR C2: 5,9 COL C
C5: 5,9,7                                # reduction candidate for 5,9
C5: 7 => CTR
* .42163..53695874215812493762389145674978562136153728.9..4721638176438952823695...
C5: 5,9                                  # 19 pairs
* PAIR F2: 7,9 BLK 2
F3: 7,9,4                                # reduction candidate for 7,9
F3: 7,9 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
F3: 4 => CTR
* .42163..536..89471.81.743262389175644..8.62.36..3.2..9..4721638176438952823695...
* PAIR F2: 7,9 ROW 2
H2: 7,9,2                                # reduction candidate for 7,9
H2: 2 => CTR
* .42163..536..87421.812493762389145674..8.621361.3.28.9..4721638176438952823695...
H2: 7,9                                  # 16 pairs
* PAIR E3: 4,7 BLK 2
F3: 4,7,9                                # reduction candidate for 4,7
F3: 4,7 => CTR
* .42163..536..89471.81...32623891.56.4.98762136173528.9..4721638176438952823695...
F3: 9 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR E3: 4,7 COL E
E6: 4,7,5                                # reduction candidate for 4,7
E6: 5 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
E6: 4,7                                  # 19 pairs
* PAIR G1: 7,8 BLK 3
H1: 7,8,9                                # reduction candidate for 7,8
H1: 7,8 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
H1: 9 => CTR
* 74216389536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
* PAIR G1: 7,8 COL G
G6: 7,8,1                                # reduction candidate for 7,8
G6: 1 => CTR
* .421638.536..8.4.1.81...3.623891.56.4..8.62.36..3.2189..47216381764389528236957..
G6: 7,8                                  # 18 pairs
* PAIR B6: 1,5 BLK 4
B5: 1,5,9                                # reduction candidate for 1,5
B5: 9 => CTR
* 74216389536958742158124937623891.56.49.8.621361.3.2..99547216381764389528236951..
B5: 1,5                                  # 16 pairs
* PAIR C6: 5,7 BLK 4
C5: 5,7,9                                # reduction candidate for 5,7
C5: 5,7 => CTR
* .42163..536958742158124937623891456749.8.621361.3.28.9..4721638176438952823695...
C5: 9                                    # 16 pairs
* PAIR C6: 5,7 ROW 6
E6: 5,7,4                                # reduction candidate for 5,7
E6: 5,7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
E6: 4 => CTR
* 74216389536..894719815743262389175644..8562.36..342..9..4721638176438952823695147
* PAIR F4: 4,7 BLK 5
E6: 4,7,5                                # reduction candidate for 4,7
E6: 5 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
E6: 4,7                                  # 19 pairs
* PAIR F4: 4,7 COL F
F3: 4,7,9                                # reduction candidate for 4,7
F3: 4,7 => CTR
* .42163..536..89471.81...32623891.56.4.98762136173528.9..4721638176438952823695...
F3: 9 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR E5: 5,7 BLK 5
E6: 5,7,4                                # reduction candidate for 5,7
E6: 5,7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
E6: 4 => CTR
* 74216389536..894719815743262389175644..8562.36..342..9..4721638176438952823695147
* PAIR E5: 5,7 ROW 5
C5: 5,7,9                                # reduction candidate for 5,7
C5: 5,7 => CTR
* .42163..536958742158124937623891456749.8.621361.3.28.9..4721638176438952823695...
C5: 9                                    # 16 pairs
* PAIR I4: 4,7 BLK 6
H6: 4,7,1,8                              # reduction candidate for 4,7
H6: 4,7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
H6: 1,8 => CTR
* 74216389536..894719815743262389175644..8562.36..342..9..4721638176438952823695147
* PAIR H5: 1,7 BLK 6
G6: 1,7,8                                # reduction candidate for 1,7
G6: 1,7 => CTR
* .421638.536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
G6: 8 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
H6: 1,7,4,8                              # reduction candidate for 1,7
H6: 1,7 => CTR
* 9421637853652874.1.81...3.623891.5644..8.62.36..3428.9..4721638176438952823695147
H6: 4,8                                  # 18 pairs
* PAIR H5: 1,7 COL H
H9: 1,7,4                                # reduction candidate for 1,7
H9: 1,7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
H9: 4 => CTR
* .42163..536..89471.81.743262389175644..8562.36..342..9..4721638176438952823695147
* PAIR A7: 5,9 COL A
A3: 5,9,7                                # reduction candidate for 5,9
A3: 5,9 => CTR
* 74216389536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
A3: 7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR B7: 5,9 COL B
B5: 5,9,1                                # reduction candidate for 5,9
B5: 1 => CTR
* .421637853652874.1.81...3.623891.56.419856273657342..9594721638176438952823695.47
B5: 5,9                                  # 17 pairs
* PAIR G9: 1,7 BLK 9
H9: 1,7,4                                # reduction candidate for 1,7
H9: 1,7 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
H9: 4 => CTR
* .42163..536..89471.81.743262389175644..8562.36..342..9..4721638176438952823695147
* PAIR G9: 1,7 COL G
G6: 1,7,8                                # reduction candidate for 1,7
G6: 1,7 => CTR
* .421638.536..8.4.1.81...3.62389175644..856213615342789.54721638176438952823695147
G6: 8 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* PAIR I9: 4,7 BLK 9
H9: 4,7,1                                # reduction candidate for 4,7
H9: 1 => CTR
* .42163..536..8.4.1.81...3.623891.56.4..8.62.36..3.2.49..4721638176438952823695.14
H9: 4,7                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-249-base-pr-000.dot
* REASONING
* DIS # A3: 5 => CTR => A3: 7,9
* DIS # H1: 7,9 => CTR => H1: 8
* PRF # H1: 8 => SOL
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* DIS # C5: 7 => CTR => C5: 5,9
* PRF # F3: 7,9 => SOL
* DIS # F3: 4 => CTR => F3: 7,9
* DIS # H2: 2 => CTR => H2: 7,9
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* PRF # E6: 5 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 9 => CTR => H1: 7,8
* DIS # G6: 1 => CTR => G6: 7,8
* DIS # B5: 9 => CTR => B5: 1,5
* DIS # C5: 5,7 => CTR => C5: 9
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* PRF # E6: 5 => SOL
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* DIS # C5: 5,7 => CTR => C5: 9
* PRF # H6: 4,7 => SOL
* DIS # H6: 1,8 => CTR => H6: 4,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # H6: 1,7 => CTR => H6: 4,8
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* DIS # B5: 1 => CTR => B5: 5,9
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # H9: 1 => CTR => H9: 4,7
* CNT  40 HDP CHAINS /  52 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A7,B6,B7,C2,C6,D2,D3,E3,E5,F2,F4,G1,G9,H5,I4,I9)
* .42163..536..8.4.1.81...3.623891.56.4..8.62.36..3.2..9..4721638176438952823695...
* PAIR A1: 7,9 BLK 1
A3: 7,9,5                                # reduction candidate for 7,9
A3: 5 => CTR
* 74216389536958742158124937623891.56.4..8.62.36..3.2..9..4721638176438952823695...
* PAIR A1: 7,9 ROW 1
H1: 7,9,8                                # reduction candidate for 7,9
H1: 7,9 => CTR
* .421638.536528.4.1.815..32623891.56.4.98.62.36.73.21895947216381764389528236957..
H1: 8 => SOLVED
* 942163785365287491781549326238914567459876213617352849594721638176438952823695174
* DURATION: 0:00:04.811045  START: 11:19:47.532270  END: 11:19:52.343315 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-249-base-pr-001.dot
* REASONING
* DIS # A3: 5 => CTR => A3: 7,9
* DIS A3: 7,9 # H1: 7,9 => CTR => H1: 8
* PRF A3: 7,9 + H1: 8 => SOL
* STA A3: 7,9 + H1: 8
* CNT   3 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 249

solution: 942163785365287491781549326238914567459876213617352849594721638176438952823695174
info: 2073     FNBWXY   S8.f     13260

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

Solution

position: 942163785365287491781549326238914567459876213617352849594721638176438952823695174 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 # A3: 7,9 => UNS
* DIS # A3: 5 => CTR => A3: 7,9
* DIS # H1: 7,9 => CTR => H1: 8
* PRF # H1: 8 => SOL
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* INC # C5: 5,9 => UNS
* DIS # C5: 7 => CTR => C5: 5,9
* PRF # F3: 7,9 => SOL
* DIS # F3: 4 => CTR => F3: 7,9
* INC # H2: 7,9 => UNS
* DIS # H2: 2 => CTR => H2: 7,9
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* INC # E6: 4,7 => UNS
* PRF # E6: 5 => SOL
* PRF # H1: 7,8 => SOL
* DIS # H1: 9 => CTR => H1: 7,8
* INC # G6: 7,8 => UNS
* DIS # G6: 1 => CTR => G6: 7,8
* INC # B5: 1,5 => UNS
* DIS # B5: 9 => CTR => B5: 1,5
* DIS # C5: 5,7 => CTR => C5: 9
* INC # C5: 9 => UNS
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* INC # E6: 4,7 => UNS
* PRF # E6: 5 => SOL
* DIS # F3: 4,7 => CTR => F3: 9
* PRF # F3: 9 => SOL
* PRF # E6: 5,7 => SOL
* DIS # E6: 4 => CTR => E6: 5,7
* DIS # C5: 5,7 => CTR => C5: 9
* INC # C5: 9 => UNS
* PRF # H6: 4,7 => SOL
* DIS # H6: 1,8 => CTR => H6: 4,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # H6: 1,7 => CTR => H6: 4,8
* INC # H6: 4,8 => UNS
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # A3: 5,9 => CTR => A3: 7
* PRF # A3: 7 => SOL
* INC # B5: 5,9 => UNS
* DIS # B5: 1 => CTR => B5: 5,9
* PRF # H9: 1,7 => SOL
* DIS # H9: 4 => CTR => H9: 1,7
* DIS # G6: 1,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* INC # H9: 4,7 => UNS
* DIS # H9: 1 => CTR => H9: 4,7
* CNT  52 HDP CHAINS /  52 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 7,9 => UNS
* DIS # A3: 5 => CTR => A3: 7,9
* DIS A3: 7,9 # H1: 7,9 => CTR => H1: 8
* PRF A3: 7,9 + H1: 8 => SOL
* STA A3: 7,9 + H1: 8
* CNT   4 HDP CHAINS /   3 HYP OPENED