Analysis of xx-top500-295-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...32....7..6.....1.....8......81....6.....3........2...4...1.7.3.4...........5.. initial

Autosolve

position: ...32..1.7..61.3..1.3...8..3...816...6.....31.1.....28..48..1.7.314..28....1..543 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I2: 5,9 => CTR => I2: 2,4
* DIS # H3: 5,9 => CTR => H3: 6,7
* DIS # I3: 5,9 => CTR => I3: 2,4,6
* DIS # F2: 5,9 => CTR => F2: 4,8
* PRF # H4: 5,9 => SOL
* DIS # H4: 7 => CTR => H4: 5,9
* DIS # H4: 7,9 => CTR => H4: 5
* PRF # H4: 5 => SOL
* PRF # G6: 7,9 => SOL
* DIS # G6: 4 => CTR => G6: 7,9
* DIS # G1: 7,9 => CTR => G1: 4
* PRF # G1: 4 => SOL
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* DIS # E8: 6,9 => CTR => E8: 5,7
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* DIS # H3: 6,9 => CTR => H3: 5,7
* PRF # H3: 5,7 => SOL
* DIS # E8: 6,9 => CTR => E8: 5,7
* PRF # I3: 6,9 => SOL
* DIS # I3: 2,4,5 => CTR => I3: 6,9
* CNT  20 HDP CHAINS /  48 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 # I2: 5,9 => CTR => I2: 2,4
* DIS I2: 2,4 # H3: 5,9 => CTR => H3: 6,7
* DIS I2: 2,4 + H3: 6,7 # I3: 5,9 => CTR => I3: 2,4,6
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 # I1: 4 => CTR => I1: 5,9
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 # F2: 5,9 => CTR => F2: 4,8
* PRF I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # G6: 7,9 => SOL
* STA I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 + G6: 7,9
* CNT   6 HDP CHAINS /  16 HYP OPENED

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

Details

Positions

...32....7..6.....1.....8......81....6.....3........2...4...1.7.3.4...........5.. initial
...32..1.7..61.3..1.3...8..3...816...6.....31.1.....28..48..1.7.314..28....1..543 autosolve
986327415745618392123954876392781654568249731417536928254893167631475289879162543 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
H2: 5,9
E6: 3,6
F6: 3,6
G5: 7,9
E9: 6,9
H7: 6,9
I8: 6,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I2,I3: 2.. / I2 = 2  =>  8 pairs (_) / I3 = 2  =>  0 pairs (X)
D4,D5: 2.. / D4 = 2  => 11 pairs (_) / D5 = 2  =>  9 pairs (_)
F7,F9: 2.. / F7 = 2  =>  9 pairs (_) / F9 = 2  =>  7 pairs (_)
B3,I3: 2.. / B3 = 2  =>  8 pairs (_) / I3 = 2  =>  0 pairs (X)
E6,F6: 3.. / E6 = 3  =>  5 pairs (_) / F6 = 3  =>  6 pairs (_)
E7,F7: 3.. / E7 = 3  =>  6 pairs (_) / F7 = 3  =>  5 pairs (_)
E6,E7: 3.. / E6 = 3  =>  5 pairs (_) / E7 = 3  =>  6 pairs (_)
F6,F7: 3.. / F6 = 3  =>  6 pairs (_) / F7 = 3  =>  5 pairs (_)
B4,A6: 4.. / B4 = 4  =>  0 pairs (X) / A6 = 4  =>  0 pairs (_)
E5,F5: 4.. / E5 = 4  =>  7 pairs (_) / F5 = 4  =>  7 pairs (_)
I4,G6: 4.. / I4 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
B4,I4: 4.. / B4 = 4  =>  0 pairs (X) / I4 = 4  =>  0 pairs (_)
A6,G6: 4.. / A6 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
A1,A6: 4.. / A1 = 4  =>  0 pairs (X) / A6 = 4  =>  0 pairs (_)
E3,E5: 4.. / E3 = 4  =>  7 pairs (_) / E5 = 4  =>  7 pairs (_)
G1,G6: 4.. / G1 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
H4,I4: 5.. / H4 = 5  =>  0 pairs (*) / I4 = 5  =>  0 pairs (X)
A1,C1: 6.. / A1 = 6  =>  0 pairs (X) / C1 = 6  =>  7 pairs (_)
H3,I3: 6.. / H3 = 6  =>  0 pairs (X) / I3 = 6  =>  0 pairs (_)
E6,F6: 6.. / E6 = 6  =>  6 pairs (_) / F6 = 6  =>  5 pairs (_)
H7,I8: 6.. / H7 = 6  =>  0 pairs (*) / I8 = 6  =>  0 pairs (X)
C1,C9: 6.. / C1 = 6  =>  7 pairs (_) / C9 = 6  =>  0 pairs (X)
H3,H7: 6.. / H3 = 6  =>  0 pairs (X) / H7 = 6  =>  0 pairs (_)
I3,I8: 6.. / I3 = 6  =>  0 pairs (*) / I8 = 6  =>  0 pairs (X)
G1,H3: 7.. / G1 = 7  =>  0 pairs (X) / H3 = 7  =>  0 pairs (_)
B9,C9: 7.. / B9 = 7  =>  7 pairs (_) / C9 = 7  =>  0 pairs (X)
E8,F8: 7.. / E8 = 7  =>  7 pairs (_) / F8 = 7  =>  0 pairs (X)
F1,G1: 7.. / F1 = 7  =>  0 pairs (*) / G1 = 7  =>  0 pairs (X)
B4,B9: 7.. / B4 = 7  =>  0 pairs (X) / B9 = 7  =>  7 pairs (_)
H3,H4: 7.. / H3 = 7  =>  0 pairs (*) / H4 = 7  =>  0 pairs (X)
F1,F2: 8.. / F1 = 8  =>  0 pairs (X) / F2 = 8  =>  7 pairs (_)
A5,C5: 8.. / A5 = 8  => 10 pairs (_) / C5 = 8  =>  7 pairs (_)
H7,I8: 9.. / H7 = 9  =>  0 pairs (X) / I8 = 9  =>  0 pairs (_)
* DURATION: 0:00:57.133364  START: 13:03:09.524978  END: 13:04:06.658342 2017-05-04
* CP COUNT: (33)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (E6,E9,F6,G5,H2,H7,I8)
* ...32..1.7..61.3..1.3...8..3...816...6.....31.1.....28..48..1.7.314..28....1..543
* PAIR H2: 5,9 BLK 3
I1: 5,9,4                                # reduction candidate for 5,9
I1: 5,9                                  # 13 pairs
I2: 5,9,2,4                              # reduction candidate for 5,9
I2: 5,9 => CTR
* 4.632.7197..61.3..1.3...8623...81675.6....931.1....428..48..197.314..286.7.1..543
I2: 2,4                                  #  8 pairs
H3: 5,9,6,7                              # reduction candidate for 5,9
H3: 5,9 => CTR
* 4..32.71.7..61.3..1.3...8.63...81675.6....931.1....428..48..167.314..289.7.1..543
H3: 6,7                                  #  8 pairs
I3: 5,9,2,4,6                            # reduction candidate for 5,9
I3: 5,9 => CTR
* 4.632.7197..61.3.2123...86.3...81675.6....931.1....428..48..197.314..286.7.1..543
I3: 2,4,6                                #  7 pairs
* PAIR H2: 5,9 ROW 2
B2: 5,9,2,4,8                            # reduction candidate for 5,9
B2: 5,9                                  # 11 pairs
C2: 5,9,2,8                              # reduction candidate for 5,9
C2: 5,9                                  # 11 pairs
F2: 5,9,4,8                              # reduction candidate for 5,9
F2: 5,9 => CTR
* 456328719782619354193...862349281675268...931.1....428.248..197.314..286.7.1.2543
F2: 4,8                                  #  8 pairs
* PAIR H2: 5,9 COL H
H4: 5,9,7                                # reduction candidate for 5,9
H4: 5,9 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
H4: 7 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
* PAIR E6: 3,6 COL E
E7: 3,6,5,9                              # reduction candidate for 3,6
E7: 3,6                                  #  9 pairs
E7: 5,9                                  #  6 pairs
* PAIR F6: 3,6 COL F
F7: 3,6,2,5,9                            # reduction candidate for 3,6
F7: 3,6                                  #  8 pairs
F7: 2,5,9                                #  7 pairs
* PAIR G5: 7,9 BLK 6
H4: 7,9,5                                # reduction candidate for 7,9
H4: 7,9 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
H4: 5 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
G6: 7,9,4                                # reduction candidate for 7,9
G6: 7,9 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
G6: 4 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
* PAIR G5: 7,9 ROW 5
C5: 7,9,2,5,8                            # reduction candidate for 7,9
C5: 7,9                                  # 15 pairs
D5: 7,9,2,5                              # reduction candidate for 7,9
D5: 7,9                                  # 14 pairs
E5: 7,9,4,5                              # reduction candidate for 7,9
E5: 7,9                                  # 10 pairs
F5: 7,9,4,5                              # reduction candidate for 7,9
F5: 7,9                                  # 10 pairs
* PAIR G5: 7,9 COL G
G1: 7,9,4                                # reduction candidate for 7,9
G1: 7,9 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
G1: 4 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
* PAIR E9: 6,9 BLK 8
E7: 6,9,3,5                              # reduction candidate for 6,9
E7: 6,9                                  # 11 pairs
F7: 6,9,2,3,5                            # reduction candidate for 6,9
F7: 6,9 => CTR
* 4.632.7197..61.35.1.3...86.34..81675.6....93151..634282548361979314..286678192543
F7: 2,3,5                                #  7 pairs
E8: 6,9,5,7                              # reduction candidate for 6,9
E8: 6,9 => CTR
* 4.632.7197..61.35.1.3...86.34298167586....93191....428..48..197531497286.79162543
E8: 5,7                                  #  8 pairs
F8: 6,9,5,7                              # reduction candidate for 6,9
F8: 6,9                                  # 12 pairs
F9: 6,9,2                                # reduction candidate for 6,9
F9: 6,9                                  #  9 pairs
* PAIR E9: 6,9 ROW 9
A9: 6,9,2,8                              # reduction candidate for 6,9
A9: 6,9                                  # 10 pairs
C9: 6,9,2,7,8                            # reduction candidate for 6,9
C9: 6,9                                  #  8 pairs
* PAIR H7: 6,9 ROW 7
A7: 6,9,2,5                              # reduction candidate for 6,9
A7: 6,9                                  # 10 pairs
E7: 6,9,3,5                              # reduction candidate for 6,9
E7: 6,9                                  # 11 pairs
F7: 6,9,2,3,5                            # reduction candidate for 6,9
F7: 6,9 => CTR
* 4.632.7197..61.35.1.3...86.34..81675.6....93151..634282548361979314..286678192543
F7: 2,3,5                                #  7 pairs
* PAIR H7: 6,9 COL H
H3: 6,9,5,7                              # reduction candidate for 6,9
H3: 6,9 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
H3: 5,7 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
* PAIR I8: 6,9 ROW 8
A8: 6,9,5                                # reduction candidate for 6,9
A8: 6,9                                  # 11 pairs
E8: 6,9,5,7                              # reduction candidate for 6,9
E8: 6,9 => CTR
* 4.632.7197..61.35.1.3...86.34298167586....93191....428..48..197531497286.79162543
E8: 5,7                                  #  8 pairs
F8: 6,9,5,7                              # reduction candidate for 6,9
F8: 6,9                                  # 12 pairs
* PAIR I8: 6,9 COL I
I3: 6,9,2,4,5                            # reduction candidate for 6,9
I3: 6,9 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
I3: 2,4,5 => CTR
* 4.632.7197.261.3541.3...862349281675268...931.1....428..48..197.314..286.7.1..543
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-295-base-pr-000.dot
* REASONING
* DIS # I2: 5,9 => CTR => I2: 2,4
* DIS # H3: 5,9 => CTR => H3: 6,7
* DIS # I3: 5,9 => CTR => I3: 2,4,6
* DIS # F2: 5,9 => CTR => F2: 4,8
* PRF # H4: 5,9 => SOL
* DIS # H4: 7 => CTR => H4: 5,9
* DIS # H4: 7,9 => CTR => H4: 5
* PRF # H4: 5 => SOL
* PRF # G6: 7,9 => SOL
* DIS # G6: 4 => CTR => G6: 7,9
* DIS # G1: 7,9 => CTR => G1: 4
* PRF # G1: 4 => SOL
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* DIS # E8: 6,9 => CTR => E8: 5,7
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* DIS # H3: 6,9 => CTR => H3: 5,7
* PRF # H3: 5,7 => SOL
* DIS # E8: 6,9 => CTR => E8: 5,7
* PRF # I3: 6,9 => SOL
* DIS # I3: 2,4,5 => CTR => I3: 6,9
* CNT  20 HDP CHAINS /  48 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (E6,E9,F6,G5,H2,H7,I8)
* ...32..1.7..61.3..1.3...8..3...816...6.....31.1.....28..48..1.7.314..28....1..543
* PAIR H2: 5,9 BLK 3
I1: 5,9,4                                # reduction candidate for 5,9
I1: 5,9                                  # 13 pairs
I2: 5,9,2,4                              # reduction candidate for 5,9
I2: 5,9 => CTR
* 4.632.7197..61.3..1.3...8623...81675.6....931.1....428..48..197.314..286.7.1..543
H3: 5,9,6,7                              # reduction candidate for 5,9
H3: 5,9 => CTR
* 4..32.71.7..61.3..1.3...8.63...81675.6....931.1....428..48..167.314..289.7.1..543
I3: 5,9,2,4,6                            # reduction candidate for 5,9
I3: 5,9 => CTR
* 4.632.7197..61.3.2123...86.3...81675.6....931.1....428..48..197.314..286.7.1..543
* RESTART
* PAIR H2: 5,9 BLK 3
I1: 5,9,4                                # reduction candidate for 5,9
I1: 4 => CTR
* ...32..147..61.352123...8.634..816.5.6.....31.1....428..48..167.314..289.7.1..543
* PAIR H2: 5,9 ROW 2
B2: 5,9,2,4,8                            # reduction candidate for 5,9
B2: 5,9                                  # 16 pairs
C2: 5,9,2,8                              # reduction candidate for 5,9
C2: 5,9                                  # 16 pairs
F2: 5,9,4,8                              # reduction candidate for 5,9
F2: 5,9 => CTR
* 456328719782619354193...862349281675268...931.1....428.248..197.314..286.7.1.2543
* PAIR RESTART
* PAIR H2: 5,9 ROW 2
B2: 5,9,2,4,8                            # reduction candidate for 5,9
B2: 5,9                                  # 16 pairs
C2: 5,9,2,8                              # reduction candidate for 5,9
C2: 5,9                                  # 16 pairs
* PAIR E6: 3,6 COL E
E7: 3,6,5,9                              # reduction candidate for 3,6
E7: 3,6                                  # 16 pairs
E7: 5,9                                  # 13 pairs
* PAIR F6: 3,6 COL F
F7: 3,6,2,5,9                            # reduction candidate for 3,6
F7: 3,6                                  # 15 pairs
F7: 2,5,9                                # 14 pairs
* PAIR G5: 7,9 BLK 6
G6: 7,9,4                                # reduction candidate for 7,9
G6: 7,9 => SOLVED
* 986327415745618392123954876392781654568249731417536928254893167631475289879162543
* DURATION: 0:00:16.838036  START: 13:04:53.193375  END: 13:05:10.031411 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-295-base-pr-001.dot
* REASONING
* DIS # I2: 5,9 => CTR => I2: 2,4
* DIS I2: 2,4 # H3: 5,9 => CTR => H3: 6,7
* DIS I2: 2,4 + H3: 6,7 # I3: 5,9 => CTR => I3: 2,4,6
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 # I1: 4 => CTR => I1: 5,9
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 # F2: 5,9 => CTR => F2: 4,8
* PRF I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # G6: 7,9 => SOL
* STA I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 + G6: 7,9
* CNT   6 HDP CHAINS /  16 HYP OPENED

Header Info

Top 500 Minimum 17 295

solution: 986327415745618392123954876392781654568249731417536928254893167631475289879162543
info: 2417     FNBTHWY  S8.f     8699

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

Solution

position: 986327415745618392123954876392781654568249731417536928254893167631475289879162543 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 # I1: 5,9 => UNS
* DIS # I2: 5,9 => CTR => I2: 2,4
* INC # I2: 2,4 => UNS
* DIS # H3: 5,9 => CTR => H3: 6,7
* INC # H3: 6,7 => UNS
* DIS # I3: 5,9 => CTR => I3: 2,4,6
* INC # I3: 2,4,6 => UNS
* INC # B2: 5,9 => UNS
* INC # C2: 5,9 => UNS
* DIS # F2: 5,9 => CTR => F2: 4,8
* INC # F2: 4,8 => UNS
* PRF # H4: 5,9 => SOL
* DIS # H4: 7 => CTR => H4: 5,9
* INC # E7: 3,6 => UNS
* INC # E7: 5,9 => UNS
* INC # F7: 3,6 => UNS
* INC # F7: 2,5,9 => UNS
* DIS # H4: 7,9 => CTR => H4: 5
* PRF # H4: 5 => SOL
* PRF # G6: 7,9 => SOL
* DIS # G6: 4 => CTR => G6: 7,9
* INC # C5: 7,9 => UNS
* INC # D5: 7,9 => UNS
* INC # E5: 7,9 => UNS
* INC # F5: 7,9 => UNS
* DIS # G1: 7,9 => CTR => G1: 4
* PRF # G1: 4 => SOL
* INC # E7: 6,9 => UNS
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* INC # F7: 2,3,5 => UNS
* DIS # E8: 6,9 => CTR => E8: 5,7
* INC # E8: 5,7 => UNS
* INC # F8: 6,9 => UNS
* INC # F9: 6,9 => UNS
* INC # A9: 6,9 => UNS
* INC # C9: 6,9 => UNS
* INC # A7: 6,9 => UNS
* INC # E7: 6,9 => UNS
* DIS # F7: 6,9 => CTR => F7: 2,3,5
* INC # F7: 2,3,5 => UNS
* DIS # H3: 6,9 => CTR => H3: 5,7
* PRF # H3: 5,7 => SOL
* INC # A8: 6,9 => UNS
* DIS # E8: 6,9 => CTR => E8: 5,7
* INC # E8: 5,7 => UNS
* INC # F8: 6,9 => UNS
* PRF # I3: 6,9 => SOL
* DIS # I3: 2,4,5 => CTR => I3: 6,9
* CNT  48 HDP CHAINS /  48 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # I1: 5,9 => UNS
* DIS # I2: 5,9 => CTR => I2: 2,4
* DIS I2: 2,4 # H3: 5,9 => CTR => H3: 6,7
* DIS I2: 2,4 + H3: 6,7 # I3: 5,9 => CTR => I3: 2,4,6
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 # I1: 5,9 => UNS
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 # I1: 4 => CTR => I1: 5,9
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 # B2: 5,9 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 # C2: 5,9 => UNS
* DIS I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 # F2: 5,9 => CTR => F2: 4,8
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # B2: 5,9 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # C2: 5,9 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # E7: 3,6 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # E7: 5,9 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # F7: 3,6 => UNS
* INC I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # F7: 2,5,9 => UNS
* PRF I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 # G6: 7,9 => SOL
* STA I2: 2,4 + H3: 6,7 + I3: 2,4,6 + I1: 5,9 + F2: 4,8 + G6: 7,9
* CNT  16 HDP CHAINS /  16 HYP OPENED