Analysis of xx-top500-477-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .6.7...8..34...............5......2.....41......6.3.........1.49..8.........5.3.. initial

Autosolve

position: .6.7...8..34...............5..9...2....541......623.........1.49..8.........5.3.8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A2: 1,2 => CTR => A2: 7,8
* PRF # I1: 1,2 => SOL
* DIS # A9: 1,2 => CTR => A9: 4,6,7
* DIS # D3: 1,2 => CTR => D3: 3,4
* DIS # A2: 1,2 => CTR => A2: 7,8
* DIS # I2: 1,2 => CTR => I2: 5,6,7,9
* PRF # D9: 1,2 => SOL
* DIS # D9: 4 => CTR => D9: 1,2
* DIS # B6: 1,4 => CTR => B6: 7,8,9
* DIS # B9: 1,4 => CTR => B9: 2,7
* DIS # G3: 4,6 => CTR => G3: 2,5,7,9
* DIS # C7: 2,3 => CTR => C7: 5,6,7,8
* DIS # D3: 2,3 => CTR => D3: 1,4
* PRF # D3: 1,4 => SOL
* CNT  14 HDP CHAINS /  31 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 # A2: 1,2 => CTR => A2: 7,8
* PRF A2: 7,8 # I1: 1,2 => SOL
* STA A2: 7,8 + I1: 1,2
* CNT   2 HDP CHAINS /   6 HYP OPENED

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

Details

Positions

.6.7...8..34...............5......2.....41......6.3.........1.49..8.........5.3.. initial
.6.7...8..34...............5..9...2....541......623.........1.49..8.........5.3.8 autosolve
169735482834296715257418936541987623326541879798623541685372194913864257472159368 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
A1: 1,2
D2: 1,2
B4: 1,4
E4: 7,8
F4: 7,8
G4: 4,6
D7: 2,3

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E8,D9: 1.. / E8 = 1  =>  0 pairs (X) / D9 = 1  =>  0 pairs (_)
G8,I8: 2.. / G8 = 2  =>  7 pairs (_) / I8 = 2  =>  7 pairs (_)
E1,I1: 3.. / E1 = 3  =>  0 pairs (*) / I1 = 3  =>  0 pairs (X)
C4,I4: 3.. / C4 = 3  =>  0 pairs (X) / I4 = 3  =>  0 pairs (_)
C8,E8: 3.. / C8 = 3  =>  0 pairs (*) / E8 = 3  =>  0 pairs (X)
A5,A7: 3.. / A5 = 3  =>  0 pairs (*) / A7 = 3  =>  0 pairs (X)
D3,D7: 3.. / D3 = 3  =>  0 pairs (X) / D7 = 3  =>  0 pairs (_)
H3,H5: 3.. / H3 = 3  =>  0 pairs (*) / H5 = 3  =>  0 pairs (X)
F1,G1: 4.. / F1 = 4  =>  0 pairs (X) / G1 = 4  =>  0 pairs (_)
B4,G4: 4.. / B4 = 4  =>  0 pairs (*) / G4 = 4  =>  0 pairs (X)
B8,F8: 4.. / B8 = 4  =>  0 pairs (X) / F8 = 4  =>  0 pairs (_)
A6,A9: 4.. / A6 = 4  =>  0 pairs (X) / A9 = 4  =>  0 pairs (_)
D3,D9: 4.. / D3 = 4  =>  0 pairs (*) / D9 = 4  =>  0 pairs (X)
H3,H6: 4.. / H3 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
E4,F4: 7.. / E4 = 7  =>  5 pairs (_) / F4 = 7  =>  6 pairs (_)
E4,F4: 8.. / E4 = 8  =>  6 pairs (_) / F4 = 8  =>  5 pairs (_)
G5,G6: 8.. / G5 = 8  =>  7 pairs (_) / G6 = 8  => 10 pairs (_)
H7,H9: 9.. / H7 = 9  =>  8 pairs (_) / H9 = 9  =>  7 pairs (_)
F9,H9: 9.. / F9 = 9  =>  8 pairs (_) / H9 = 9  =>  7 pairs (_)
* DURATION: 0:00:27.985556  START: 19:00:06.843433  END: 19:00:34.828989 2017-05-04
* CP COUNT: (19)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B4,D2,D7,E4,F4,G4)
* .6.7...8..34...............5..9...2....541......623.........1.49..8.........5.3.8
* PAIR A1: 1,2 BLK 1
C1: 1,2,5,9                              # reduction candidate for 1,2
C1: 1,2                                  # 15 pairs
A2: 1,2,7,8                              # reduction candidate for 1,2
A2: 1,2 => CTR
* .6.7...8..34...............5..9...2....541.3....623...3..2..1.49..83.......15.3.8
A2: 7,8                                  #  8 pairs
A3: 1,2,7,8                              # reduction candidate for 1,2
A3: 1,2                                  # 10 pairs
B3: 1,2,5,7,8,9                          # reduction candidate for 1,2
B3: 1,2                                  # 17 pairs
C3: 1,2,5,7,8,9                          # reduction candidate for 1,2
C3: 1,2                                  # 14 pairs
* PAIR A1: 1,2 ROW 1
I1: 1,2,3,5,9                            # reduction candidate for 1,2
I1: 1,2 => SOLVED
* 169735482834296715257418936541987623326541879798623541685372194913864257472159368
I1: 3,5,9                                #  7 pairs
* PAIR A1: 1,2 COL A
A9: 1,2,4,6,7                            # reduction candidate for 1,2
A9: 1,2 => CTR
* .6.7...8..34.............4.51.9..42....541.3.4..623...3..2..1.49..83........5.3.8
A9: 4,6,7                                #  7 pairs
* PAIR D2: 1,2 BLK 2
D3: 1,2,3,4                              # reduction candidate for 1,2
D3: 1,2 => CTR
* .6.7...8..34...............5..9...233..541...4..623......3..1.494381.......45.3.8
D3: 3,4                                  #  8 pairs
* PAIR D2: 1,2 ROW 2
A2: 1,2,7,8                              # reduction candidate for 1,2
A2: 1,2 => CTR
* .6.7...8..34...............5..9...2....541.3....623...3..2..1.49..83.......15.3.8
A2: 7,8                                  #  8 pairs
I2: 1,2,5,6,7,9                          # reduction candidate for 1,2
I2: 1,2 => CTR
* .6.7...8..34...............5..9...2....541.3....623...3..2..1.49..83.......15.3.8
I2: 5,6,7,9                              #  7 pairs
* PAIR D2: 1,2 COL D
D9: 1,2,4                                # reduction candidate for 1,2
D9: 1,2 => SOLVED
* 169735482834296715257418936541987623326541879798623541685372194913864257472159368
D9: 4 => CTR
* .6.7...8..34.............4.5169..4233..541...4..623.........1.494381.......45.3.8
* PAIR B4: 1,4 BLK 4
A6: 1,4,7,8                              # reduction candidate for 1,4
A6: 1,4                                  #  9 pairs
B6: 1,4,7,8,9                            # reduction candidate for 1,4
B6: 1,4 => CTR
* .6.7..48..34.........4.....54.9..621...541....1.623.4....3..1.49.38.4...4...5.3.8
B6: 7,8,9                                #  7 pairs
* PAIR B4: 1,4 COL B
B8: 1,4,5,7                              # reduction candidate for 1,4
B8: 1,4                                  #  9 pairs
B9: 1,4,2,7                              # reduction candidate for 1,4
B9: 1,4 => CTR
* .6.7..48..341........4...1.5419..6233.6541.79...623.416..3..1.49.3814...417256398
B9: 2,7                                  #  8 pairs
* PAIR G4: 4,6 COL G
G3: 4,6,2,5,7,9                          # reduction candidate for 4,6
G3: 4,6 => CTR
* .6.7.4.8..34............64.51.9..42....541.3.4..623...3..2..1.494.81.......45.3.8
G3: 2,5,7,9                              #  7 pairs
* PAIR D7: 2,3 ROW 7
A7: 2,3,6,7,8                            # reduction candidate for 2,3
A7: 2,3                                  #  8 pairs
C7: 2,3,5,6,7,8                          # reduction candidate for 2,3
C7: 2,3 => CTR
* .6.73..8..34....1....41..3.5419..6233.6541.79...6235416823..1.49.38.....4...5.3.8
C7: 5,6,7,8                              #  7 pairs
* PAIR D7: 2,3 COL D
D3: 2,3,1,4                              # reduction candidate for 2,3
D3: 2,3 => CTR
* .6.7...8..341............4.51.9..42....541.3.4..623.1.3..2..1.494.81.......45.3.8
D3: 1,4 => SOLVED
* 169735482834296715257418936541987623326541879798623541685372194913864257472159368
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-477-base-pr-000.dot
* REASONING
* DIS # A2: 1,2 => CTR => A2: 7,8
* PRF # I1: 1,2 => SOL
* DIS # A9: 1,2 => CTR => A9: 4,6,7
* DIS # D3: 1,2 => CTR => D3: 3,4
* DIS # A2: 1,2 => CTR => A2: 7,8
* DIS # I2: 1,2 => CTR => I2: 5,6,7,9
* PRF # D9: 1,2 => SOL
* DIS # D9: 4 => CTR => D9: 1,2
* DIS # B6: 1,4 => CTR => B6: 7,8,9
* DIS # B9: 1,4 => CTR => B9: 2,7
* DIS # G3: 4,6 => CTR => G3: 2,5,7,9
* DIS # C7: 2,3 => CTR => C7: 5,6,7,8
* DIS # D3: 2,3 => CTR => D3: 1,4
* PRF # D3: 1,4 => SOL
* CNT  14 HDP CHAINS /  31 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,B4,D2,D7,E4,F4,G4)
* .6.7...8..34...............5..9...2....541......623.........1.49..8.........5.3.8
* PAIR A1: 1,2 BLK 1
C1: 1,2,5,9                              # reduction candidate for 1,2
C1: 1,2                                  # 15 pairs
A2: 1,2,7,8                              # reduction candidate for 1,2
A2: 1,2 => CTR
* .6.7...8..34...............5..9...2....541.3....623...3..2..1.49..83.......15.3.8
A3: 1,2,7,8                              # reduction candidate for 1,2
A3: 1,2                                  # 10 pairs
B3: 1,2,5,7,8,9                          # reduction candidate for 1,2
B3: 1,2                                  # 17 pairs
C3: 1,2,5,7,8,9                          # reduction candidate for 1,2
C3: 1,2                                  # 14 pairs
* PAIR A1: 1,2 ROW 1
I1: 1,2,3,5,9                            # reduction candidate for 1,2
I1: 1,2 => SOLVED
* 169735482834296715257418936541987623326541879798623541685372194913864257472159368
* DURATION: 0:00:06.032121  START: 19:00:56.508659  END: 19:01:02.540780 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-477-base-pr-001.dot
* REASONING
* DIS # A2: 1,2 => CTR => A2: 7,8
* PRF A2: 7,8 # I1: 1,2 => SOL
* STA A2: 7,8 + I1: 1,2
* CNT   2 HDP CHAINS /   6 HYP OPENED

Header Info

Top 500 Minimum 17 477

solution: 169735482834296715257418936541987623326541879798623541685372194913864257472159368
info: 95757    FNBHWYK  S8.f     21582

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

Solution

position: 169735482834296715257418936541987623326541879798623541685372194913864257472159368 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 # C1: 1,2 => UNS
* DIS # A2: 1,2 => CTR => A2: 7,8
* INC # A2: 7,8 => UNS
* INC # A3: 1,2 => UNS
* INC # B3: 1,2 => UNS
* INC # C3: 1,2 => UNS
* PRF # I1: 1,2 => SOL
* INC # I1: 3,5,9 => UNS
* DIS # A9: 1,2 => CTR => A9: 4,6,7
* INC # A9: 4,6,7 => UNS
* DIS # D3: 1,2 => CTR => D3: 3,4
* INC # D3: 3,4 => UNS
* DIS # A2: 1,2 => CTR => A2: 7,8
* INC # A2: 7,8 => UNS
* DIS # I2: 1,2 => CTR => I2: 5,6,7,9
* INC # I2: 5,6,7,9 => UNS
* PRF # D9: 1,2 => SOL
* DIS # D9: 4 => CTR => D9: 1,2
* INC # A6: 1,4 => UNS
* DIS # B6: 1,4 => CTR => B6: 7,8,9
* INC # B6: 7,8,9 => UNS
* INC # B8: 1,4 => UNS
* DIS # B9: 1,4 => CTR => B9: 2,7
* INC # B9: 2,7 => UNS
* DIS # G3: 4,6 => CTR => G3: 2,5,7,9
* INC # G3: 2,5,7,9 => UNS
* INC # A7: 2,3 => UNS
* DIS # C7: 2,3 => CTR => C7: 5,6,7,8
* INC # C7: 5,6,7,8 => UNS
* DIS # D3: 2,3 => CTR => D3: 1,4
* PRF # D3: 1,4 => SOL
* CNT  31 HDP CHAINS /  31 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C1: 1,2 => UNS
* DIS # A2: 1,2 => CTR => A2: 7,8
* INC A2: 7,8 # A3: 1,2 => UNS
* INC A2: 7,8 # B3: 1,2 => UNS
* INC A2: 7,8 # C3: 1,2 => UNS
* PRF A2: 7,8 # I1: 1,2 => SOL
* STA A2: 7,8 + I1: 1,2
* CNT   6 HDP CHAINS /   6 HYP OPENED