Analysis of xx-top500-439-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ......23..1..5....7..6..........34.96...2......8.........8...61..2.......5....... initial

Autosolve

position: 56..8123.81325....72.63....2751634896.1.28.....8..5.....78.2561.825.6....563..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # H2: 4,7 => SOL
* DIS # I2: 4,7 => CTR => I2: 6
* PRF # H2: 4,7 => SOL
* DIS # I2: 4,7 => CTR => I2: 6
* DIS # I8: 4,7 => CTR => I8: 3
* DIS # I5: 3,7 => CTR => I5: 5
* DIS # I5: 3 => CTR => I5: 5,7
* CNT   7 HDP CHAINS /  44 HYP OPENED

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

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* PRF # H2: 4,7 => SOL
* STA H2: 4,7
* CNT   1 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

......23..1..5....7..6..........34.96...2......8.........8...61..2.......5....... initial
56..8123.81325....72.63....2751634896.1.28.....8..5.....78.2561.825.6....563..... autosolve
564981237813257946729634158275163489691428375348795612937842561482516793156379824 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
C1: 4,9
C3: 4,9
F2: 4,7
F3: 4,9
I1: 4,7
G3: 1,8
H3: 1,5
I3: 5,8
B5: 4,9
D5: 4,9
G5: 3,7
H5: 5,7
G6: 1,6
H6: 1,2
I6: 2,6
E7: 4,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G3,H3: 1.. / G3 = 1  => 14 pairs (_) / H3 = 1  =>  0 pairs (X)
G6,H6: 1.. / G6 = 1  =>  0 pairs (X) / H6 = 1  => 14 pairs (_)
A8,A9: 1.. / A8 = 1  => 17 pairs (_) / A9 = 1  => 18 pairs (_)
E8,E9: 1.. / E8 = 1  => 18 pairs (_) / E9 = 1  => 17 pairs (_)
A8,E8: 1.. / A8 = 1  => 17 pairs (_) / E8 = 1  => 18 pairs (_)
A9,E9: 1.. / A9 = 1  => 18 pairs (_) / E9 = 1  => 17 pairs (_)
G3,G6: 1.. / G3 = 1  => 14 pairs (_) / G6 = 1  =>  0 pairs (X)
H3,H6: 1.. / H3 = 1  =>  0 pairs (X) / H6 = 1  => 14 pairs (_)
H6,I6: 2.. / H6 = 2  =>  0 pairs (X) / I6 = 2  => 14 pairs (_)
H9,I9: 2.. / H9 = 2  => 14 pairs (_) / I9 = 2  =>  0 pairs (X)
H6,H9: 2.. / H6 = 2  =>  0 pairs (X) / H9 = 2  => 14 pairs (_)
I6,I9: 2.. / I6 = 2  => 14 pairs (_) / I9 = 2  =>  0 pairs (X)
A6,B6: 3.. / A6 = 3  => 18 pairs (_) / B6 = 3  => 18 pairs (_)
G5,I5: 3.. / G5 = 3  => 17 pairs (_) / I5 = 3  =>  0 pairs (X)
A7,B7: 3.. / A7 = 3  => 18 pairs (_) / B7 = 3  => 18 pairs (_)
G8,I8: 3.. / G8 = 3  =>  0 pairs (X) / I8 = 3  => 17 pairs (_)
A6,A7: 3.. / A6 = 3  => 18 pairs (_) / A7 = 3  => 18 pairs (_)
B6,B7: 3.. / B6 = 3  => 18 pairs (_) / B7 = 3  => 18 pairs (_)
G5,G8: 3.. / G5 = 3  => 17 pairs (_) / G8 = 3  =>  0 pairs (X)
I5,I8: 3.. / I5 = 3  =>  0 pairs (X) / I8 = 3  => 17 pairs (_)
C1,C3: 4.. / C1 = 4  => 18 pairs (_) / C3 = 4  => 16 pairs (_)
C3,F3: 4.. / C3 = 4  => 16 pairs (_) / F3 = 4  => 18 pairs (_)
B5,D5: 4.. / B5 = 4  => 18 pairs (_) / D5 = 4  => 21 pairs (_)
H3,I3: 5.. / H3 = 5  => 14 pairs (_) / I3 = 5  =>  0 pairs (X)
H5,I5: 5.. / H5 = 5  =>  0 pairs (X) / I5 = 5  => 14 pairs (_)
H3,H5: 5.. / H3 = 5  => 14 pairs (_) / H5 = 5  =>  0 pairs (X)
I3,I5: 5.. / I3 = 5  =>  0 pairs (X) / I5 = 5  => 14 pairs (_)
G2,I2: 6.. / G2 = 6  =>  0 pairs (X) / I2 = 6  => 14 pairs (_)
G6,I6: 6.. / G6 = 6  => 14 pairs (_) / I6 = 6  =>  0 pairs (X)
G2,G6: 6.. / G2 = 6  =>  0 pairs (X) / G6 = 6  => 14 pairs (_)
I2,I6: 6.. / I2 = 6  => 14 pairs (_) / I6 = 6  =>  0 pairs (X)
D1,F2: 7.. / D1 = 7  => 17 pairs (_) / F2 = 7  => 24 pairs (_)
D6,E6: 7.. / D6 = 7  => 24 pairs (_) / E6 = 7  => 17 pairs (_)
D1,I1: 7.. / D1 = 7  => 17 pairs (_) / I1 = 7  => 24 pairs (_)
D1,D6: 7.. / D1 = 7  => 17 pairs (_) / D6 = 7  => 24 pairs (_)
F2,F9: 7.. / F2 = 7  => 24 pairs (_) / F9 = 7  => 17 pairs (_)
G3,I3: 8.. / G3 = 8  =>  0 pairs (X) / I3 = 8  => 14 pairs (_)
G9,I9: 8.. / G9 = 8  => 14 pairs (_) / I9 = 8  =>  0 pairs (X)
G3,G9: 8.. / G3 = 8  =>  0 pairs (X) / G9 = 8  => 14 pairs (_)
I3,I9: 8.. / I3 = 8  => 14 pairs (_) / I9 = 8  =>  0 pairs (X)
C1,C3: 9.. / C1 = 9  => 16 pairs (_) / C3 = 9  => 18 pairs (_)
D1,F3: 9.. / D1 = 9  => 18 pairs (_) / F3 = 9  => 16 pairs (_)
G2,H2: 9.. / G2 = 9  =>  0 pairs (*) / H2 = 9  =>  0 pairs (X)
C1,D1: 9.. / C1 = 9  => 16 pairs (_) / D1 = 9  => 18 pairs (_)
C3,F3: 9.. / C3 = 9  => 18 pairs (_) / F3 = 9  => 16 pairs (_)
B5,D5: 9.. / B5 = 9  => 21 pairs (_) / D5 = 9  => 18 pairs (_)
F3,F9: 9.. / F3 = 9  => 16 pairs (_) / F9 = 9  => 18 pairs (_)
* DURATION: 0:01:22.271868  START: 17:45:53.173004  END: 17:47:15.444872 2017-05-04
* CP COUNT: (47)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B5,C1,C3,D5,E7,F2,F3,G3,G5,G6,H3,H5,H6,I1,I3,I6)
* 56..8123.81325....72.63....2751634896.1.28.....8..5.....78.2561.825.6....563.....
* PAIR C1: 4,9 ROW 1
D1: 4,9,7                                # reduction candidate for 4,9
D1: 4,9                                  # 24 pairs
D1: 7                                    # 17 pairs
* PAIR F2: 4,7 BLK 2
D1: 4,7,9                                # reduction candidate for 4,7
D1: 9                                    # 18 pairs
D1: 4,7                                  # 16 pairs
* PAIR F2: 4,7 ROW 2
H2: 4,7,9                                # reduction candidate for 4,7
H2: 4,7 => SOLVED
* 564981237813257946729634158275163489691428375348795612937842561482516793156379824
H2: 9                                    # 19 pairs
I2: 4,7,6                                # reduction candidate for 4,7
I2: 4,7 => CTR
* 56..8123.81325.69.72.63.8152751634896.1.28.5...8..5126..78.2561.825.6....563....2
I2: 6                                    # 14 pairs
* PAIR F2: 4,7 COL F
F9: 4,7,9                                # reduction candidate for 4,7
F9: 9                                    # 18 pairs
F9: 4,7                                  # 16 pairs
* PAIR F3: 4,9 BLK 2
D1: 4,9,7                                # reduction candidate for 4,9
D1: 4,9                                  # 24 pairs
D1: 7                                    # 17 pairs
* PAIR F3: 4,9 COL F
F9: 4,9,7                                # reduction candidate for 4,9
F9: 4,9                                  # 24 pairs
F9: 7                                    # 17 pairs
* PAIR I1: 4,7 BLK 3
H2: 4,7,9                                # reduction candidate for 4,7
H2: 4,7 => SOLVED
* 564981237813257946729634158275163489691428375348795612937842561482516793156379824
H2: 9                                    # 19 pairs
I2: 4,7,6                                # reduction candidate for 4,7
I2: 4,7 => CTR
* 56..8123.81325.69.72.63.8152751634896.1.28.5...8..5126..78.2561.825.6....563....2
I2: 6                                    # 14 pairs
* PAIR I1: 4,7 ROW 1
D1: 4,7,9                                # reduction candidate for 4,7
D1: 9                                    # 18 pairs
D1: 4,7                                  # 16 pairs
* PAIR I1: 4,7 COL I
I8: 4,7,3                                # reduction candidate for 4,7
I8: 4,7 => CTR
* 56..8123.81325....72.63.8152751634896.1.28753..8..512...78.2561.825.63...563....8
I8: 3                                    # 17 pairs
I9: 4,7,2,8                              # reduction candidate for 4,7
I9: 4,7                                  # 14 pairs
* PAIR B5: 4,9 BLK 4
A6: 4,9,3                                # reduction candidate for 4,9
A6: 4,9                                  # 18 pairs
B6: 4,9,3                                # reduction candidate for 4,9
B6: 4,9                                  # 18 pairs
* PAIR B5: 4,9 COL B
B7: 4,9,3                                # reduction candidate for 4,9
B7: 4,9                                  # 18 pairs
B7: 3                                    # 18 pairs
* PAIR D5: 4,9 BLK 5
D6: 4,9,7                                # reduction candidate for 4,9
D6: 4,9                                  # 17 pairs
E6: 4,9,7                                # reduction candidate for 4,9
E6: 4,9                                  # 24 pairs
* PAIR D5: 4,9 COL D
D1: 4,9,7                                # reduction candidate for 4,9
D1: 4,9                                  # 24 pairs
D1: 7                                    # 17 pairs
* PAIR G5: 3,7 BLK 6
I5: 3,7,5                                # reduction candidate for 3,7
I5: 3,7 => CTR
* 56..8123.81325....72.63.8152751634896.1.28.5...8..512...78.2561.825.6....563....8
I5: 5                                    # 14 pairs
* PAIR G5: 3,7 COL G
G8: 3,7,9                                # reduction candidate for 3,7
G8: 9                                    # 20 pairs
G8: 3,7                                  # 19 pairs
* PAIR H5: 5,7 BLK 6
I5: 5,7,3                                # reduction candidate for 5,7
I5: 3 => CTR
* 56..8123.81325....72.63.8152751634896.1.28753..8..512...78.2561.825.63...563....8
I5: 5,7                                  # 17 pairs
* PAIR E7: 4,9 BLK 8
E8: 4,9,1,7                              # reduction candidate for 4,9
E8: 4,9                                  # 19 pairs
E9: 4,9,1,7                              # reduction candidate for 4,9
E9: 4,9                                  # 19 pairs
F9: 4,9,7                                # reduction candidate for 4,9
F9: 4,9                                  # 24 pairs
* PAIR E7: 4,9 ROW 7
A7: 4,9,3                                # reduction candidate for 4,9
A7: 4,9                                  # 18 pairs
B7: 4,9,3                                # reduction candidate for 4,9
B7: 4,9                                  # 18 pairs
* PAIR E7: 4,9 COL E
E6: 4,9,7                                # reduction candidate for 4,9
E6: 4,9                                  # 24 pairs
E6: 7                                    # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-439-base-pr-000.dot
* REASONING
* PRF # H2: 4,7 => SOL
* DIS # I2: 4,7 => CTR => I2: 6
* PRF # H2: 4,7 => SOL
* DIS # I2: 4,7 => CTR => I2: 6
* DIS # I8: 4,7 => CTR => I8: 3
* DIS # I5: 3,7 => CTR => I5: 5
* DIS # I5: 3 => CTR => I5: 5,7
* CNT   7 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B5,C1,C3,D5,E7,F2,F3,G3,G5,G6,H3,H5,H6,I1,I3,I6)
* 56..8123.81325....72.63....2751634896.1.28.....8..5.....78.2561.825.6....563.....
* PAIR C1: 4,9 ROW 1
D1: 4,9,7                                # reduction candidate for 4,9
D1: 4,9                                  # 24 pairs
D1: 7                                    # 17 pairs
* PAIR F2: 4,7 BLK 2
D1: 4,7,9                                # reduction candidate for 4,7
D1: 9                                    # 18 pairs
D1: 4,7                                  # 16 pairs
* PAIR F2: 4,7 ROW 2
H2: 4,7,9                                # reduction candidate for 4,7
H2: 4,7 => SOLVED
* 564981237813257946729634158275163489691428375348795612937842561482516793156379824
* DURATION: 0:00:06.173597  START: 17:47:57.252106  END: 17:48:03.425703 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-439-base-pr-001.dot
* REASONING
* PRF # H2: 4,7 => SOL
* STA H2: 4,7
* CNT   1 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 439

solution: 564981237813257946729634158275163489691428375348795612937842561482516793156379824
info: 95250    FNBTHXYK S8.f     45385

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

Solution

position: 564981237813257946729634158275163489691428375348795612937842561482516793156379824 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 # D1: 4,9 => UNS
* INC # D1: 7 => UNS
* INC # D1: 4,7 => UNS
* INC # D1: 9 => UNS
* PRF # H2: 4,7 => SOL
* INC # H2: 9 => UNS
* DIS # I2: 4,7 => CTR => I2: 6
* INC # I2: 6 => UNS
* INC # F9: 4,7 => UNS
* INC # F9: 9 => UNS
* INC # D1: 4,9 => UNS
* INC # D1: 7 => UNS
* INC # F9: 4,9 => UNS
* INC # F9: 7 => UNS
* PRF # H2: 4,7 => SOL
* INC # H2: 9 => UNS
* DIS # I2: 4,7 => CTR => I2: 6
* INC # I2: 6 => UNS
* INC # D1: 4,7 => UNS
* INC # D1: 9 => UNS
* DIS # I8: 4,7 => CTR => I8: 3
* INC # I8: 3 => UNS
* INC # I9: 4,7 => UNS
* INC # A6: 4,9 => UNS
* INC # B6: 4,9 => UNS
* INC # B7: 4,9 => UNS
* INC # B7: 3 => UNS
* INC # D6: 4,9 => UNS
* INC # E6: 4,9 => UNS
* INC # D1: 4,9 => UNS
* INC # D1: 7 => UNS
* DIS # I5: 3,7 => CTR => I5: 5
* INC # I5: 5 => UNS
* INC # G8: 3,7 => UNS
* INC # G8: 9 => UNS
* INC # I5: 5,7 => UNS
* DIS # I5: 3 => CTR => I5: 5,7
* INC # E8: 4,9 => UNS
* INC # E9: 4,9 => UNS
* INC # F9: 4,9 => UNS
* INC # A7: 4,9 => UNS
* INC # B7: 4,9 => UNS
* INC # E6: 4,9 => UNS
* INC # E6: 7 => UNS
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D1: 4,9 => UNS
* INC # D1: 7 => UNS
* INC # D1: 4,7 => UNS
* INC # D1: 9 => UNS
* PRF # H2: 4,7 => SOL
* STA H2: 4,7
* CNT   5 HDP CHAINS /   5 HYP OPENED