Analysis of xx-top500-087-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 47..........5..1.........3..4......2....34.......8.6..8.1....4......75.....2..... initial

Autosolve

position: 47..........54.1........43..4....3.2....34.......826.48.1....4....4.75..7.42.89.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D1: 6,9 => CTR => D1: 1,3,8
* PRF # E1: 6,9 => SOL
* DIS # E1: 2 => CTR => E1: 6,9
* DIS # F1: 6,9 => CTR => F1: 1,3
* DIS # F2: 6,9 => CTR => F2: 3
* DIS # D3: 6,9 => CTR => D3: 7,8
* DIS # E3: 6,9 => CTR => E3: 2,7
* DIS # F4: 6,9 => CTR => F4: 1,5
* DIS # H1: 2,8 => CTR => H1: 5,6,9
* PRF # H2: 2,8 => SOL
* DIS # H2: 6,7,9 => CTR => H2: 2,8
* DIS # C1: 2,8 => CTR => C1: 3,5,6,9
* DIS # I5: 7,8 => CTR => I5: 1,5,9
* DIS # I2: 8,9 => CTR => I2: 6,7
* DIS # H8: 1,6 => CTR => H8: 2,8
* DIS # I8: 1,6 => CTR => I8: 3,8
* DIS # I9: 1,6 => CTR => I9: 3
* DIS # E9: 5 => CTR => E9: 1,6
* CNT  18 HDP CHAINS /  41 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 # D1: 6,9 => CTR => D1: 1,3,8
* PRF D1: 1,3,8 # E1: 6,9 => SOL
* STA D1: 1,3,8 + E1: 6,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

47..........5..1.........3..4......2....34.......8.6..8.1....4......75.....2..... initial
47..........54.1........43..4....3.2....34.......826.48.1....4....4.75..7.42.89.. autosolve
473891265269543187185726439648175392592634871317982654821359746936417528754268913 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (6)
F3: 6,9
G1: 2,8
G5: 7,8
G7: 2,7
I7: 6,7
H9: 1,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A3,B3: 1.. / A3 = 1  =>  7 pairs (_) / B3 = 1  =>  7 pairs (_)
D1,F1: 1.. / D1 = 1  =>  0 pairs (X) / F1 = 1  =>  6 pairs (_)
E8,E9: 1.. / E8 = 1  =>  7 pairs (_) / E9 = 1  =>  0 pairs (X)
F1,F4: 1.. / F1 = 1  =>  6 pairs (_) / F4 = 1  =>  0 pairs (X)
E1,E3: 2.. / E1 = 2  =>  0 pairs (X) / E3 = 2  =>  0 pairs (_)
G7,H8: 2.. / G7 = 2  =>  0 pairs (X) / H8 = 2  =>  0 pairs (_)
B7,G7: 2.. / B7 = 2  =>  0 pairs (*) / G7 = 2  =>  0 pairs (X)
G1,G7: 2.. / G1 = 2  =>  0 pairs (*) / G7 = 2  =>  0 pairs (X)
D7,F7: 3.. / D7 = 3  =>  6 pairs (_) / F7 = 3  =>  0 pairs (X)
I8,I9: 3.. / I8 = 3  =>  0 pairs (X) / I9 = 3  =>  7 pairs (_)
B9,I9: 3.. / B9 = 3  =>  0 pairs (X) / I9 = 3  =>  7 pairs (_)
D1,D7: 3.. / D1 = 3  =>  0 pairs (X) / D7 = 3  =>  6 pairs (_)
E4,F4: 5.. / E4 = 5  =>  0 pairs (X) / F4 = 5  =>  6 pairs (_)
B7,B9: 5.. / B7 = 5  =>  0 pairs (X) / B9 = 5  =>  7 pairs (_)
B9,E9: 5.. / B9 = 5  =>  7 pairs (_) / E9 = 5  =>  0 pairs (X)
F4,F7: 5.. / F4 = 5  =>  6 pairs (_) / F7 = 5  =>  0 pairs (X)
D3,E3: 7.. / D3 = 7  =>  0 pairs (*) / E3 = 7  =>  0 pairs (X)
H2,I2: 7.. / H2 = 7  =>  0 pairs (X) / I2 = 7  =>  0 pairs (_)
G7,I7: 7.. / G7 = 7  =>  0 pairs (*) / I7 = 7  =>  0 pairs (X)
E3,E4: 7.. / E3 = 7  =>  0 pairs (X) / E4 = 7  =>  0 pairs (_)
G5,G7: 7.. / G5 = 7  =>  0 pairs (X) / G7 = 7  =>  0 pairs (_)
D1,D3: 8.. / D1 = 8  =>  0 pairs (*) / D3 = 8  =>  0 pairs (X)
H8,I8: 8.. / H8 = 8  =>  0 pairs (X) / I8 = 8  =>  7 pairs (_)
C4,H4: 8.. / C4 = 8  =>  6 pairs (_) / H4 = 8  =>  0 pairs (X)
G1,G5: 8.. / G1 = 8  =>  0 pairs (X) / G5 = 8  =>  0 pairs (_)
* DURATION: 0:00:35.775510  START: 05:45:25.534498  END: 05:46:01.310008 2017-05-04
* CP COUNT: (25)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (F3,G1,G5,G7,H9,I7)
* 47..........54.1........43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
* PAIR F3: 6,9 BLK 2
D1: 6,9,1,3,8                            # reduction candidate for 6,9
D1: 6,9 => CTR
* 473.218.....543127...87.43..4....3.2....347......826.48.13...4....4.75..7.42.89..
D1: 1,3,8                                #  6 pairs
E1: 6,9,2                                # reduction candidate for 6,9
E1: 6,9 => SOLVED
* 473891265269543187185726439648175392592634871317982654821359746936417528754268913
E1: 2 => CTR
* 47..2.8.....54.127...87.43..4....3.2....347......826.48.1....4....4.75..7.42.89..
F1: 6,9,1,3                              # reduction candidate for 6,9
F1: 6,9 => CTR
* 47312.8.....543127...87.43..4..513.2....347......826.48.13.5.4....4.75..7542.89.3
F1: 1,3                                  #  7 pairs
F2: 6,9,3                                # reduction candidate for 6,9
F2: 6,9 => CTR
* 47..2.8.....54.127...87.43..4....3.2....347......826.48.1....4....4.75..7.42.89..
F2: 3                                    #  6 pairs
D3: 6,9,7,8                              # reduction candidate for 6,9
D3: 6,9 => CTR
* 47.8.12.....5431........43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
D3: 7,8                                  #  7 pairs
E3: 6,9,2,7                              # reduction candidate for 6,9
E3: 6,9 => CTR
* 47..2.8.....54.127......43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
E3: 2,7                                  #  7 pairs
* PAIR F3: 6,9 ROW 3
A3: 6,9,1,2,5                            # reduction candidate for 6,9
A3: 6,9                                  # 11 pairs
B3: 6,9,1,2,8                            # reduction candidate for 6,9
B3: 6,9                                  # 11 pairs
C3: 6,9,2,5,8                            # reduction candidate for 6,9
C3: 6,9                                  # 10 pairs
I3: 6,9,5,8                              # reduction candidate for 6,9
I3: 6,9                                  #  9 pairs
* PAIR F3: 6,9 COL F
F4: 6,9,1,5                              # reduction candidate for 6,9
F4: 6,9 => CTR
* 473.218.....543127...87.43..4..5.3.2....347......826.48.13.5.4....4.75..7542.89.3
F4: 1,5                                  #  7 pairs
F7: 6,9,3,5                              # reduction candidate for 6,9
F7: 6,9                                  #  7 pairs
* PAIR G1: 2,8 BLK 3
H1: 2,8,5,6,9                            # reduction candidate for 2,8
H1: 2,8 => CTR
* 47..........54.1.....8..43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
H1: 5,6,9                                #  6 pairs
H2: 2,8,6,7,9                            # reduction candidate for 2,8
H2: 2,8 => SOLVED
* 473891265269543187185726439648175392592634871317982654821359746936417528754268913
H2: 6,7,9 => CTR
* 47.8.12.....5431.....72.43..4..753.2....348......826.482135974....4.75..7.42.89..
* PAIR G1: 2,8 ROW 1
C1: 2,8,3,5,6,9                          # reduction candidate for 2,8
C1: 2,8 => CTR
* 47..........54.1........43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
C1: 3,5,6,9                              #  6 pairs
* PAIR G5: 7,8 BLK 6
H4: 7,8,1,9                              # reduction candidate for 7,8
H4: 7,8                                  #  7 pairs
H5: 7,8,1,5,9                            # reduction candidate for 7,8
H5: 7,8                                  #  9 pairs
I5: 7,8,1,5,9                            # reduction candidate for 7,8
I5: 7,8 => CTR
* 47....82....54.17....8..43..4....3.2....347.8....826.48.1...247...4.758.7.42.896.
I5: 1,5,9                                #  6 pairs
* PAIR G5: 7,8 ROW 5
C5: 7,8,2,5,6,9                          # reduction candidate for 7,8
C5: 7,8                                  #  7 pairs
C5: 2,5,6,9                              #  6 pairs
* PAIR I7: 6,7 COL I
I2: 6,7,8,9                              # reduction candidate for 6,7
I2: 8,9 => CTR
* 47.8.12.....54317....72.43..4..753.2....348.7..7.826.482135974....4.75..7.42.89..
I2: 6,7                                  #  8 pairs
* PAIR H9: 1,6 BLK 9
H8: 1,6,2,8                              # reduction candidate for 1,6
H8: 1,6 => CTR
* 47..2.8.....54.17....87.43..4....3.2....347.1....826.48.1...247...4.75.87.42.89.3
H8: 2,8                                  #  7 pairs
I8: 1,6,3,8                              # reduction candidate for 1,6
I8: 1,6 => CTR
* 47..2.8...8.54.17....87.43..487..3.2....347.8..7.826.48.1...247...4.7581754218963
I8: 3,8                                  #  7 pairs
I9: 1,6,3                                # reduction candidate for 1,6
I9: 1,6 => CTR
* 47..218...8.54.17....87.43..487.53.2....347.83.7.82654851...247...417583734258961
I9: 3                                    #  7 pairs
* PAIR H9: 1,6 ROW 9
E9: 1,6,5                                # reduction candidate for 1,6
E9: 5 => CTR
* 47..218.....54.17....87.43..4...53.2....347......826.4851...247...4175..7.42589..
E9: 1,6                                  #  7 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-087-base-pr-000.dot
* REASONING
* DIS # D1: 6,9 => CTR => D1: 1,3,8
* PRF # E1: 6,9 => SOL
* DIS # E1: 2 => CTR => E1: 6,9
* DIS # F1: 6,9 => CTR => F1: 1,3
* DIS # F2: 6,9 => CTR => F2: 3
* DIS # D3: 6,9 => CTR => D3: 7,8
* DIS # E3: 6,9 => CTR => E3: 2,7
* DIS # F4: 6,9 => CTR => F4: 1,5
* DIS # H1: 2,8 => CTR => H1: 5,6,9
* PRF # H2: 2,8 => SOL
* DIS # H2: 6,7,9 => CTR => H2: 2,8
* DIS # C1: 2,8 => CTR => C1: 3,5,6,9
* DIS # I5: 7,8 => CTR => I5: 1,5,9
* DIS # I2: 8,9 => CTR => I2: 6,7
* DIS # H8: 1,6 => CTR => H8: 2,8
* DIS # I8: 1,6 => CTR => I8: 3,8
* DIS # I9: 1,6 => CTR => I9: 3
* DIS # E9: 5 => CTR => E9: 1,6
* CNT  18 HDP CHAINS /  41 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (F3,G1,G5,G7,H9,I7)
* 47..........54.1........43..4....3.2....34.......826.48.1....4....4.75..7.42.89..
* PAIR F3: 6,9 BLK 2
D1: 6,9,1,3,8                            # reduction candidate for 6,9
D1: 6,9 => CTR
* 473.218.....543127...87.43..4....3.2....347......826.48.13...4....4.75..7.42.89..
E1: 6,9,2                                # reduction candidate for 6,9
E1: 6,9 => SOLVED
* 473891265269543187185726439648175392592634871317982654821359746936417528754268913
* DURATION: 0:00:03.392595  START: 05:46:30.359873  END: 05:46:33.752468 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-087-base-pr-001.dot
* REASONING
* DIS # D1: 6,9 => CTR => D1: 1,3,8
* PRF D1: 1,3,8 # E1: 6,9 => SOL
* STA D1: 1,3,8 + E1: 6,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 087

solution: 473891265269543187185726439648175392592634871317982654821359746936417528754268913
info: 1559     FNBHXY   S8.f     31766

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

Solution

position: 473891265269543187185726439648175392592634871317982654821359746936417528754268913 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:

* DIS # D1: 6,9 => CTR => D1: 1,3,8
* INC # D1: 1,3,8 => UNS
* PRF # E1: 6,9 => SOL
* DIS # E1: 2 => CTR => E1: 6,9
* DIS # F1: 6,9 => CTR => F1: 1,3
* INC # F1: 1,3 => UNS
* DIS # F2: 6,9 => CTR => F2: 3
* INC # F2: 3 => UNS
* DIS # D3: 6,9 => CTR => D3: 7,8
* INC # D3: 7,8 => UNS
* DIS # E3: 6,9 => CTR => E3: 2,7
* INC # E3: 2,7 => UNS
* INC # A3: 6,9 => UNS
* INC # B3: 6,9 => UNS
* INC # C3: 6,9 => UNS
* INC # I3: 6,9 => UNS
* DIS # F4: 6,9 => CTR => F4: 1,5
* INC # F4: 1,5 => UNS
* INC # F7: 6,9 => UNS
* DIS # H1: 2,8 => CTR => H1: 5,6,9
* INC # H1: 5,6,9 => UNS
* PRF # H2: 2,8 => SOL
* DIS # H2: 6,7,9 => CTR => H2: 2,8
* DIS # C1: 2,8 => CTR => C1: 3,5,6,9
* INC # C1: 3,5,6,9 => UNS
* INC # H4: 7,8 => UNS
* INC # H5: 7,8 => UNS
* DIS # I5: 7,8 => CTR => I5: 1,5,9
* INC # I5: 1,5,9 => UNS
* INC # C5: 7,8 => UNS
* INC # C5: 2,5,6,9 => UNS
* INC # I2: 6,7 => UNS
* DIS # I2: 8,9 => CTR => I2: 6,7
* DIS # H8: 1,6 => CTR => H8: 2,8
* INC # H8: 2,8 => UNS
* DIS # I8: 1,6 => CTR => I8: 3,8
* INC # I8: 3,8 => UNS
* DIS # I9: 1,6 => CTR => I9: 3
* INC # I9: 3 => UNS
* INC # E9: 1,6 => UNS
* DIS # E9: 5 => CTR => E9: 1,6
* CNT  41 HDP CHAINS /  41 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D1: 6,9 => CTR => D1: 1,3,8
* PRF D1: 1,3,8 # E1: 6,9 => SOL
* STA D1: 1,3,8 + E1: 6,9
* CNT   2 HDP CHAINS /   2 HYP OPENED