Analysis of xx-top500-393-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 8.......14..6........3......6.....3.1...8..........6...58....7..1..2.......4..9.. initial

Autosolve

position: 8.......14..6........3......6.....3.143.86....8....6...58....7..1482.......4..9.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A9: 2,7 => CTR => A9: 3,6
* DIS # C9: 2,7 => CTR => C9: 6
* DIS # B1: 2,7 => CTR => B1: 3,9
* DIS # E7: 1,9 => CTR => E7: 3,6
* DIS # F7: 1,9 => CTR => F7: 3
* DIS # G7: 2,4 => CTR => G7: 1
* PRF # G7: 1 => SOL
* DIS # I3: 2,4 => CTR => I3: 5,6,7,8,9
* DIS # I4: 2,4 => CTR => I4: 5,7,8,9
* DIS # I6: 2,4 => CTR => I6: 5,7,9
* DIS # I8: 3,5 => CTR => I8: 6
* DIS # I8: 3 => CTR => I8: 5,6
* DIS # H3: 5,6 => CTR => H3: 2,4,8,9
* PRF # H9: 2,8 => SOL
* DIS # H9: 1 => CTR => H9: 2,8
* DIS # I2: 2,8 => CTR => I2: 3,5,7,9
* DIS # I3: 2,8 => CTR => I3: 4,5,6,7,9
* PRF # I4: 2,8 => SOL
* DIS # I4: 4,5,7,9 => CTR => I4: 2,8
* CNT  19 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:

* DIS # A9: 2,7 => CTR => A9: 3,6
* DIS A9: 3,6 # C9: 2,7 => CTR => C9: 6
* DIS A9: 3,6 + C9: 6 # G7: 2,4 => CTR => G7: 1
* PRF A9: 3,6 + C9: 6 + G7: 1 => SOL
* STA A9: 3,6 + C9: 6 + G7: 1
* CNT   4 HDP CHAINS /  10 HYP OPENED

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

Details

Positions

8.......14..6........3......6.....3.1...8..........6...58....7..1..2.......4..9.. initial
8.......14..6........3......6.....3.143.86....8....6...58....7..1482.......4..9.. autosolve
837549261425618793691372845762195438143786529589234617258963174914827356376451982 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
A8: 7,9
B9: 2,7
D7: 1,9
F8: 7,9
I7: 2,4
G8: 3,5
H8: 5,6
I9: 2,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C2,C3: 1.. / C2 = 1  =>  8 pairs (_) / C3 = 1  =>  8 pairs (_)
G4,H6: 1.. / G4 = 1  =>  0 pairs (X) / H6 = 1  =>  0 pairs (_)
G7,H9: 1.. / G7 = 1  =>  0 pairs (*) / H9 = 1  =>  0 pairs (X)
G4,G7: 1.. / G4 = 1  =>  0 pairs (X) / G7 = 1  =>  0 pairs (_)
H6,H9: 1.. / H6 = 1  =>  0 pairs (*) / H9 = 1  =>  0 pairs (X)
B1,B2: 3.. / B1 = 3  =>  8 pairs (_) / B2 = 3  =>  0 pairs (X)
E6,F6: 3.. / E6 = 3  =>  8 pairs (_) / F6 = 3  =>  0 pairs (X)
A7,A9: 3.. / A7 = 3  =>  0 pairs (X) / A9 = 3  =>  8 pairs (_)
G8,I8: 3.. / G8 = 3  =>  8 pairs (_) / I8 = 3  =>  0 pairs (X)
B1,G1: 3.. / B1 = 3  =>  8 pairs (_) / G1 = 3  =>  0 pairs (X)
I2,I8: 3.. / I2 = 3  =>  8 pairs (_) / I8 = 3  =>  0 pairs (X)
G7,I7: 4.. / G7 = 4  =>  0 pairs (X) / I7 = 4  =>  0 pairs (_)
E9,F9: 5.. / E9 = 5  =>  8 pairs (_) / F9 = 5  =>  8 pairs (_)
E7,E9: 6.. / E7 = 6  =>  8 pairs (_) / E9 = 6  =>  0 pairs (X)
H8,I8: 6.. / H8 = 6  =>  0 pairs (X) / I8 = 6  =>  7 pairs (_)
C1,H1: 6.. / C1 = 6  =>  0 pairs (X) / H1 = 6  =>  7 pairs (_)
A7,E7: 6.. / A7 = 6  =>  0 pairs (X) / E7 = 6  =>  8 pairs (_)
I3,I8: 6.. / I3 = 6  =>  0 pairs (X) / I8 = 6  =>  7 pairs (_)
A8,F8: 7.. / A8 = 7  =>  0 pairs (X) / F8 = 7  =>  6 pairs (_)
F2,F3: 8.. / F2 = 8  =>  8 pairs (_) / F3 = 8  =>  8 pairs (_)
G4,I4: 8.. / G4 = 8  =>  0 pairs (X) / I4 = 8  =>  0 pairs (_)
H9,I9: 8.. / H9 = 8  =>  0 pairs (*) / I9 = 8  =>  0 pairs (X)
C4,C6: 9.. / C4 = 9  =>  8 pairs (_) / C6 = 9  =>  8 pairs (_)
A7,A8: 9.. / A7 = 9  =>  0 pairs (X) / A8 = 9  =>  6 pairs (_)
A8,F8: 9.. / A8 = 9  =>  6 pairs (_) / F8 = 9  =>  0 pairs (X)
* DURATION: 0:00:33.228350  START: 16:16:35.337581  END: 16:17:08.565931 2017-05-04
* CP COUNT: (25)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B9,D7,F8,G8,H8,I7,I9)
* 8.......14..6........3......6.....3.143.86....8....6...58....7..1482.......4..9..
* PAIR B9: 2,7 BLK 7
A9: 2,7,3,6                              # reduction candidate for 2,7
A9: 2,7 => CTR
* 83.....614..6....36..3......6....83.143.86....8....61.358.6..7.914827356..64..9.8
A9: 3,6                                  #  9 pairs
C9: 2,7,6                                # reduction candidate for 2,7
C9: 2,7 => CTR
* 8.......14..6........3......6....138143.86....8....6...58....7..1482.......4..9..
C9: 6                                    #  7 pairs
* PAIR B9: 2,7 COL B
B1: 2,7,3,9                              # reduction candidate for 2,7
B1: 2,7 => CTR
* 8.6...3.143.6......9.3....6.6....138143.86....8....6...58....7..1482.563...4..9..
B1: 3,9                                  #  9 pairs
B2: 2,7,3,9                              # reduction candidate for 2,7
B2: 2,7                                  #  9 pairs
B3: 2,7,9                                # reduction candidate for 2,7
B3: 2,7                                  # 11 pairs
* PAIR D7: 1,9 BLK 8
E7: 1,9,3,6                              # reduction candidate for 1,9
E7: 1,9 => CTR
* 8.......14..6........3......6.....3.143.86....8....6..658..3.7.914827...3..465918
E7: 3,6                                  #  9 pairs
F7: 1,9,3                                # reduction candidate for 1,9
F7: 1,9 => CTR
* 8.......14..6........3......6....138143.86....8....6...58....7.914827......4..9..
F7: 3                                    #  8 pairs
* PAIR D7: 1,9 COL D
D4: 1,9,2,5,7                            # reduction candidate for 1,9
D4: 1,9                                  #  9 pairs
D6: 1,9,2,5,7                            # reduction candidate for 1,9
D6: 1,9                                  #  9 pairs
* PAIR F8: 7,9 COL F
F1: 7,9,2,4,5                            # reduction candidate for 7,9
F1: 7,9                                  # 10 pairs
F2: 7,9,1,2,5,8                          # reduction candidate for 7,9
F2: 7,9                                  # 10 pairs
F3: 7,9,1,2,4,5,8                        # reduction candidate for 7,9
F3: 7,9                                  # 10 pairs
F4: 7,9,1,2,4,5                          # reduction candidate for 7,9
F4: 7,9                                  # 10 pairs
F6: 7,9,1,2,3,4,5                        # reduction candidate for 7,9
F6: 7,9                                  # 10 pairs
* PAIR I7: 2,4 BLK 9
G7: 2,4,1                                # reduction candidate for 2,4
G7: 2,4 => CTR
* 8.......14..6........3......6....138143.86....8....6...58....7..1482.......4..9..
G7: 1 => SOLVED
* 837549261425618793691372845762195438143786529589234617258963174914827356376451982
* PAIR I7: 2,4 COL I
I3: 2,4,5,6,7,8,9                        # reduction candidate for 2,4
I3: 2,4 => CTR
* 83......14..6....3...3......6.....3.143.86....8....6...58....7..1482.356...4..9..
I3: 5,6,7,8,9                            #  8 pairs
I4: 2,4,5,7,8,9                          # reduction candidate for 2,4
I4: 2,4 => CTR
* 8.......14..6........3......6....83.143.86....8....61..58...174.1482.......4..9..
I4: 5,7,8,9                              #  8 pairs
I6: 2,4,5,7,9                            # reduction candidate for 2,4
I6: 2,4 => CTR
* 8.......14..6........3......6....83.143.86....8....614.58....7..1482.......4..9.8
I6: 5,7,9                                # 10 pairs
* PAIR G8: 3,5 BLK 9
I8: 3,5,6                                # reduction candidate for 3,5
I8: 3,5 => CTR
* 8.6.....14..6........3....6.6....138143.86....8....6...58....7..1482..6....4..9..
I8: 6                                    #  7 pairs
* PAIR G8: 3,5 COL G
G1: 3,5,2,4,7                            # reduction candidate for 3,5
G1: 3,5                                  # 10 pairs
G2: 3,5,2,7,8                            # reduction candidate for 3,5
G2: 3,5                                  # 10 pairs
* PAIR H8: 5,6 BLK 9
I8: 5,6,3                                # reduction candidate for 5,6
I8: 3 => CTR
* 8.6.....14..6........3....6.6....138143.86....8....6...58....7..1482.563...4..9..
I8: 5,6                                  #  8 pairs
* PAIR H8: 5,6 COL H
H1: 5,6,2,4,9                            # reduction candidate for 5,6
H1: 5,6                                  # 10 pairs
H3: 5,6,2,4,8,9                          # reduction candidate for 5,6
H3: 5,6 => CTR
* 8.6.....14..6........3......6....138143.86....8....6...58....7..1482.......4..9..
H3: 2,4,8,9                              #  8 pairs
* PAIR I9: 2,8 BLK 9
H9: 2,8,1                                # reduction candidate for 2,8
H9: 2,8 => SOLVED
* 837549261425618793691372845762195438143786529589234617258963174914827356376451982
H9: 1 => CTR
* 8.......14..6........3......6.....3.143.86....8....6...58....7..1482.......4..918
* PAIR I9: 2,8 COL I
I2: 2,8,3,5,7,9                          # reduction candidate for 2,8
I2: 2,8 => CTR
* 8.6.....14..6........3....6.6.....3.143.86....8....6...58....7..1482.563...4..9..
I2: 3,5,7,9                              #  8 pairs
I3: 2,8,4,5,6,7,9                        # reduction candidate for 2,8
I3: 2,8 => CTR
* 83......14..6....3...3......6.....3.143.86....8....6...58....7..1482.356...4..9..
I3: 4,5,6,7,9                            #  8 pairs
I4: 2,8,4,5,7,9                          # reduction candidate for 2,8
I4: 2,8 => SOLVED
* 837549261425618793691372845762195438143786529589234617258963174914827356376451982
I4: 4,5,7,9 => CTR
* 8.......14..6........3......6....83.143.86....8....61..58...174.1482.......4..9..
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-393-base-pr-000.dot
* REASONING
* DIS # A9: 2,7 => CTR => A9: 3,6
* DIS # C9: 2,7 => CTR => C9: 6
* DIS # B1: 2,7 => CTR => B1: 3,9
* DIS # E7: 1,9 => CTR => E7: 3,6
* DIS # F7: 1,9 => CTR => F7: 3
* DIS # G7: 2,4 => CTR => G7: 1
* PRF # G7: 1 => SOL
* DIS # I3: 2,4 => CTR => I3: 5,6,7,8,9
* DIS # I4: 2,4 => CTR => I4: 5,7,8,9
* DIS # I6: 2,4 => CTR => I6: 5,7,9
* DIS # I8: 3,5 => CTR => I8: 6
* DIS # I8: 3 => CTR => I8: 5,6
* DIS # H3: 5,6 => CTR => H3: 2,4,8,9
* PRF # H9: 2,8 => SOL
* DIS # H9: 1 => CTR => H9: 2,8
* DIS # I2: 2,8 => CTR => I2: 3,5,7,9
* DIS # I3: 2,8 => CTR => I3: 4,5,6,7,9
* PRF # I4: 2,8 => SOL
* DIS # I4: 4,5,7,9 => CTR => I4: 2,8
* CNT  19 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,B9,D7,F8,G8,H8,I7,I9)
* 8.......14..6........3......6.....3.143.86....8....6...58....7..1482.......4..9..
* PAIR B9: 2,7 BLK 7
A9: 2,7,3,6                              # reduction candidate for 2,7
A9: 2,7 => CTR
* 83.....614..6....36..3......6....83.143.86....8....61.358.6..7.914827356..64..9.8
C9: 2,7,6                                # reduction candidate for 2,7
C9: 2,7 => CTR
* 8.......14..6........3......6....138143.86....8....6...58....7..1482.......4..9..
* RESTART
* PAIR B9: 2,7 COL B
B2: 2,7,9                                # reduction candidate for 2,7
B2: 2,7                                  # 12 pairs
B3: 2,7,9                                # reduction candidate for 2,7
B3: 2,7                                  # 10 pairs
* PAIR D7: 1,9 COL D
D4: 1,9,2,5,7                            # reduction candidate for 1,9
D4: 1,9                                  #  9 pairs
D6: 1,9,2,5,7                            # reduction candidate for 1,9
D6: 1,9                                  #  9 pairs
* PAIR F8: 7,9 COL F
F1: 7,9,2,4,5                            # reduction candidate for 7,9
F1: 7,9                                  # 10 pairs
F4: 7,9,1,2,4,5                          # reduction candidate for 7,9
F4: 7,9                                  # 10 pairs
F6: 7,9,1,2,4,5                          # reduction candidate for 7,9
F6: 7,9                                  # 10 pairs
* PAIR I7: 2,4 BLK 9
G7: 2,4,1                                # reduction candidate for 2,4
G7: 2,4 => CTR
* 83.....614..6....36..3......6....138143.86....8..3.6...58163.7..148293563.64..9..
G7: 1 => SOLVED
* 837549261425618793691372845762195438143786529589234617258963174914827356376451982
* DURATION: 0:00:11.743155  START: 16:17:39.881125  END: 16:17:51.624280 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-393-base-pr-001.dot
* REASONING
* DIS # A9: 2,7 => CTR => A9: 3,6
* DIS A9: 3,6 # C9: 2,7 => CTR => C9: 6
* DIS A9: 3,6 + C9: 6 # G7: 2,4 => CTR => G7: 1
* PRF A9: 3,6 + C9: 6 + G7: 1 => SOL
* STA A9: 3,6 + C9: 6 + G7: 1
* CNT   4 HDP CHAINS /  10 HYP OPENED

Header Info

Top 500 Minimum 17 393

solution: 837549261425618793691372845762195438143786529589234617258963174914827356376451982
info: 58462    FNBHK    S8.f     44590

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

Solution

position: 837549261425618793691372845762195438143786529589234617258963174914827356376451982 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 # A9: 2,7 => CTR => A9: 3,6
* INC # A9: 3,6 => UNS
* DIS # C9: 2,7 => CTR => C9: 6
* INC # C9: 6 => UNS
* DIS # B1: 2,7 => CTR => B1: 3,9
* INC # B1: 3,9 => UNS
* INC # B2: 2,7 => UNS
* INC # B3: 2,7 => UNS
* DIS # E7: 1,9 => CTR => E7: 3,6
* INC # E7: 3,6 => UNS
* DIS # F7: 1,9 => CTR => F7: 3
* INC # F7: 3 => UNS
* INC # D4: 1,9 => UNS
* INC # D6: 1,9 => UNS
* INC # F1: 7,9 => UNS
* INC # F2: 7,9 => UNS
* INC # F3: 7,9 => UNS
* INC # F4: 7,9 => UNS
* INC # F6: 7,9 => UNS
* DIS # G7: 2,4 => CTR => G7: 1
* PRF # G7: 1 => SOL
* DIS # I3: 2,4 => CTR => I3: 5,6,7,8,9
* INC # I3: 5,6,7,8,9 => UNS
* DIS # I4: 2,4 => CTR => I4: 5,7,8,9
* INC # I4: 5,7,8,9 => UNS
* DIS # I6: 2,4 => CTR => I6: 5,7,9
* INC # I6: 5,7,9 => UNS
* DIS # I8: 3,5 => CTR => I8: 6
* INC # I8: 6 => UNS
* INC # G1: 3,5 => UNS
* INC # G2: 3,5 => UNS
* INC # I8: 5,6 => UNS
* DIS # I8: 3 => CTR => I8: 5,6
* INC # H1: 5,6 => UNS
* DIS # H3: 5,6 => CTR => H3: 2,4,8,9
* INC # H3: 2,4,8,9 => UNS
* PRF # H9: 2,8 => SOL
* DIS # H9: 1 => CTR => H9: 2,8
* DIS # I2: 2,8 => CTR => I2: 3,5,7,9
* INC # I2: 3,5,7,9 => UNS
* DIS # I3: 2,8 => CTR => I3: 4,5,6,7,9
* INC # I3: 4,5,6,7,9 => UNS
* PRF # I4: 2,8 => SOL
* DIS # I4: 4,5,7,9 => CTR => I4: 2,8
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A9: 2,7 => CTR => A9: 3,6
* DIS A9: 3,6 # C9: 2,7 => CTR => C9: 6
* INC A9: 3,6 + C9: 6 # B2: 2,7 => UNS
* INC A9: 3,6 + C9: 6 # B3: 2,7 => UNS
* INC A9: 3,6 + C9: 6 # D4: 1,9 => UNS
* INC A9: 3,6 + C9: 6 # D6: 1,9 => UNS
* INC A9: 3,6 + C9: 6 # F1: 7,9 => UNS
* INC A9: 3,6 + C9: 6 # F4: 7,9 => UNS
* INC A9: 3,6 + C9: 6 # F6: 7,9 => UNS
* DIS A9: 3,6 + C9: 6 # G7: 2,4 => CTR => G7: 1
* PRF A9: 3,6 + C9: 6 + G7: 1 => SOL
* STA A9: 3,6 + C9: 6 + G7: 1
* CNT  11 HDP CHAINS /  10 HYP OPENED