Analysis of xx-top500-449-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .5.2.8.........7.....5.....7...3.6........28...1......4...7...1.8.....5....9..... initial

Autosolve

position: .572.8..6......7.5...5.7...7...3.61....7..28...1...57.4...7...1.8.....57.7.9..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B3: 3,9 => CTR => B3: 1,2,4,6
* DIS # G1: 3,9 => CTR => G1: 1,4
* DIS # A5: 3,9 => CTR => A5: 5,6
* PRF # A6: 3,9 => SOL
* DIS # A8: 3,9 => CTR => A8: 1,2,6
* DIS # D6: 4,8 => CTR => D6: 6
* PRF # C4: 4,8 => SOL
* DIS # C4: 2,5,9 => CTR => C4: 4,8
* DIS # B4: 4,9 => CTR => B4: 2
* DIS # C4: 4,9 => CTR => C4: 2,5,8
* DIS # F4: 4,9 => CTR => F4: 2,5
* DIS # E9: 2,8 => CTR => E9: 1,4,5,6
* PRF # E9: 1,4,5,6 => SOL
* CNT  13 HDP CHAINS /  28 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 # B3: 3,9 => CTR => B3: 1,2,4,6
* DIS B3: 1,2,4,6 # G1: 3,9 => CTR => G1: 1,4
* DIS B3: 1,2,4,6 + G1: 1,4 # A5: 3,9 => CTR => A5: 5,6
* PRF B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 # A6: 3,9 => SOL
* STA B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 + A6: 3,9
* CNT   4 HDP CHAINS /   9 HYP OPENED

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

Details

Positions

.5.2.8.........7.....5.....7...3.6........28...1......4...7...1.8.....5....9..... initial
.572.8..6......7.5...5.7...7...3.61....7..28...1...57.4...7...1.8.....57.7.9..... autosolve
357298146842163795619547832728435619564719283931682574495876321186324957273951468 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (5)
A1: 3,9
I3: 2,8
D4: 4,8
I4: 4,9
I9: 2,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,B3: 1.. / B2 = 1  =>  0 pairs (X) / B3 = 1  =>  6 pairs (_)
G1,G3: 1.. / G1 = 1  =>  6 pairs (_) / G3 = 1  =>  0 pairs (X)
E5,F5: 1.. / E5 = 1  =>  0 pairs (*) / F5 = 1  =>  0 pairs (X)
A8,A9: 1.. / A8 = 1  =>  0 pairs (*) / A9 = 1  =>  0 pairs (X)
E1,G1: 1.. / E1 = 1  =>  0 pairs (X) / G1 = 1  =>  6 pairs (_)
D2,D8: 1.. / D2 = 1  =>  9 pairs (_) / D8 = 1  =>  0 pairs (X)
I3,I9: 2.. / I3 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
D2,F2: 3.. / D2 = 3  =>  0 pairs (X) / F2 = 3  =>  5 pairs (_)
I5,I6: 3.. / I5 = 3  =>  6 pairs (_) / I6 = 3  =>  6 pairs (_)
C4,F4: 5.. / C4 = 5  =>  0 pairs (X) / F4 = 5  =>  0 pairs (_)
C7,F7: 5.. / C7 = 5  =>  0 pairs (*) / F7 = 5  =>  0 pairs (X)
A5,A9: 5.. / A5 = 5  =>  0 pairs (*) / A9 = 5  =>  0 pairs (X)
E5,E9: 5.. / E5 = 5  =>  0 pairs (X) / E9 = 5  =>  0 pairs (_)
H7,H9: 6.. / H7 = 6  =>  6 pairs (_) / H9 = 6  =>  5 pairs (_)
A2,C2: 8.. / A2 = 8  =>  0 pairs (*) / C2 = 8  =>  0 pairs (X)
G3,I3: 8.. / G3 = 8  =>  0 pairs (*) / I3 = 8  =>  0 pairs (X)
C4,A6: 8.. / C4 = 8  =>  0 pairs (*) / A6 = 8  =>  0 pairs (X)
D7,E9: 8.. / D7 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
C4,D4: 8.. / C4 = 8  =>  0 pairs (*) / D4 = 8  =>  0 pairs (X)
D7,G7: 8.. / D7 = 8  =>  0 pairs (*) / G7 = 8  =>  0 pairs (X)
A2,A6: 8.. / A2 = 8  =>  0 pairs (*) / A6 = 8  =>  0 pairs (X)
C2,C4: 8.. / C2 = 8  =>  0 pairs (X) / C4 = 8  =>  0 pairs (_)
E6,E9: 8.. / E6 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
I3,I9: 8.. / I3 = 8  =>  3 pairs (_) / I9 = 8  =>  0 pairs (*)
* DURATION: 0:00:36.925856  START: 18:05:25.916508  END: 18:06:02.842364 2017-05-04
* CP COUNT: (24)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,D4,I3,I4,I9)
* .572.8..6......7.5...5.7...7...3.61....7..28...1...57.4...7...1.8.....57.7.9.....
* PAIR A1: 3,9 BLK 1
A3: 3,9,2,6                              # reduction candidate for 3,9
A3: 3,9                                  #  7 pairs
B3: 3,9,1,2,4,6                          # reduction candidate for 3,9
B3: 3,9 => CTR
* .572.8..681.3.97.52..5.7..87.84356195..79128...168257.4.587...168.12..5717295....
B3: 1,2,4,6                              #  5 pairs
C3: 3,9,2,4,6                            # reduction candidate for 3,9
C3: 3,9                                  #  7 pairs
* PAIR A1: 3,9 ROW 1
G1: 3,9,1,4                              # reduction candidate for 3,9
G1: 3,9 => CTR
* .57218.4681.3.97252..5.71.87...3561.5..7.128...1.8257.4.587...1.8.12.45717.9548.2
G1: 1,4                                  #  6 pairs
H1: 3,9,4                                # reduction candidate for 3,9
H1: 3,9                                  #  8 pairs
* PAIR A1: 3,9 COL A
A5: 3,9,5,6                              # reduction candidate for 3,9
A5: 3,9 => CTR
* .572.81.6...1.37.5.1.5.7...7.583.61....75128.8.1...57.4...758.118.....5757.91...2
A5: 5,6                                  #  6 pairs
A6: 3,9,2,6,8                            # reduction candidate for 3,9
A6: 3,9 => SOLVED
* 357298146842163795619547832728435619564719283931682574495876321186324957273951468
A6: 2,6,8                                #  5 pairs
A8: 3,9,1,2,6                            # reduction candidate for 3,9
A8: 3,9 => CTR
* .572.8..68.....7.52..5.7..87.84356195..7..28.6.1.8257.4.587...1.8..2..5717.95....
A8: 1,2,6                                #  5 pairs
* PAIR D4: 4,8 BLK 5
D6: 4,8,6                                # reduction candidate for 4,8
D6: 4,8 => CTR
* .572.8..6......7.5...5.7..87...3.61....75128...1...57.4...7.8.1.8.....57.7.98...2
D6: 6                                    #  6 pairs
E6: 4,8,2,6,9                            # reduction candidate for 4,8
E6: 4,8                                  #  8 pairs
* PAIR D4: 4,8 ROW 4
C4: 4,8,2,5,9                            # reduction candidate for 4,8
C4: 4,8 => SOLVED
* 357298146842163795619547832728435619564719283931682574495876321186324957273951468
C4: 2,5,9 => CTR
* .572.8..6..8...7.5...5.7..87..83.61....75128.8.1...57.4...7.8.1.8.....57.7.98...2
* PAIR I4: 4,9 BLK 6
I5: 4,9,3                                # reduction candidate for 4,9
I5: 4,9                                  #  6 pairs
I6: 4,9,3                                # reduction candidate for 4,9
I6: 4,9                                  #  6 pairs
* PAIR I4: 4,9 ROW 4
B4: 4,9,2                                # reduction candidate for 4,9
B4: 4,9 => CTR
* .572.8..6..8...7.5...5.7..87..83.61....75128.8.1...57.4...7.8.1.8.....57.7.98...2
B4: 2                                    #  5 pairs
C4: 4,9,2,5,8                            # reduction candidate for 4,9
C4: 4,9 => CTR
* .572.8..6..8...7.5...5.7...7..83561....7..28.8.1...57.4.5.7.8.1.8.....57.7.9.....
C4: 2,5,8                                #  5 pairs
F4: 4,9,2,5                              # reduction candidate for 4,9
F4: 4,9 => CTR
* .572.8..6......7.5...5.7...7.583.61....7..28.8.1...57.4...758.1.8.....5757.981..2
F4: 2,5                                  #  6 pairs
* PAIR I9: 2,8 ROW 9
E9: 2,8,1,4,5,6                          # reduction candidate for 2,8
E9: 2,8 => CTR
* .572.8..6......7.5...5.7...7...3.61....75128...1...57.4...7...1.8.....57.7.9.....
E9: 1,4,5,6 => SOLVED
* 357298146842163795619547832728435619564719283931682574495876321186324957273951468
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-449-base-pr-000.dot
* REASONING
* DIS # B3: 3,9 => CTR => B3: 1,2,4,6
* DIS # G1: 3,9 => CTR => G1: 1,4
* DIS # A5: 3,9 => CTR => A5: 5,6
* PRF # A6: 3,9 => SOL
* DIS # A8: 3,9 => CTR => A8: 1,2,6
* DIS # D6: 4,8 => CTR => D6: 6
* PRF # C4: 4,8 => SOL
* DIS # C4: 2,5,9 => CTR => C4: 4,8
* DIS # B4: 4,9 => CTR => B4: 2
* DIS # C4: 4,9 => CTR => C4: 2,5,8
* DIS # F4: 4,9 => CTR => F4: 2,5
* DIS # E9: 2,8 => CTR => E9: 1,4,5,6
* PRF # E9: 1,4,5,6 => SOL
* CNT  13 HDP CHAINS /  28 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,D4,I3,I4,I9)
* .572.8..6......7.5...5.7...7...3.61....7..28...1...57.4...7...1.8.....57.7.9.....
* PAIR A1: 3,9 BLK 1
A3: 3,9,2,6                              # reduction candidate for 3,9
A3: 3,9                                  #  7 pairs
B3: 3,9,1,2,4,6                          # reduction candidate for 3,9
B3: 3,9 => CTR
* .572.8..681.3.97.52..5.7..87.84356195..79128...168257.4.587...168.12..5717295....
C3: 3,9,2,4,6                            # reduction candidate for 3,9
C3: 3,9                                  #  7 pairs
* PAIR A1: 3,9 ROW 1
G1: 3,9,1,4                              # reduction candidate for 3,9
G1: 3,9 => CTR
* .57218.4681.3.97252..5.71.87...3561.5..7.128...1.8257.4.587...1.8.12.45717.9548.2
H1: 3,9,4                                # reduction candidate for 3,9
H1: 3,9                                  #  8 pairs
* RESTART
* PAIR A1: 3,9 ROW 1
H1: 3,9,4                                # reduction candidate for 3,9
H1: 3,9                                  #  8 pairs
H1: 4                                    #  5 pairs
* PAIR A1: 3,9 COL A
A5: 3,9,5,6                              # reduction candidate for 3,9
A5: 3,9 => CTR
* .572.81.6...1.37.5.1.5.7...7.583.61....75128.8.1...57.4...758.118.....5757.91...2
A6: 3,9,2,6,8                            # reduction candidate for 3,9
A6: 3,9 => SOLVED
* 357298146842163795619547832728435619564719283931682574495876321186324957273951468
* DURATION: 0:00:09.402971  START: 18:06:25.314901  END: 18:06:34.717872 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-449-base-pr-001.dot
* REASONING
* DIS # B3: 3,9 => CTR => B3: 1,2,4,6
* DIS B3: 1,2,4,6 # G1: 3,9 => CTR => G1: 1,4
* DIS B3: 1,2,4,6 + G1: 1,4 # A5: 3,9 => CTR => A5: 5,6
* PRF B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 # A6: 3,9 => SOL
* STA B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 + A6: 3,9
* CNT   4 HDP CHAINS /   9 HYP OPENED

Header Info

Top 500 Minimum 17 449

solution: 357298146842163795619547832728435619564719283931682574495876321186324957273951468
info: 95365    FNBWYK   S8.f     20176

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

Solution

position: 357298146842163795619547832728435619564719283931682574495876321186324957273951468 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 # A3: 3,9 => UNS
* DIS # B3: 3,9 => CTR => B3: 1,2,4,6
* INC # B3: 1,2,4,6 => UNS
* INC # C3: 3,9 => UNS
* DIS # G1: 3,9 => CTR => G1: 1,4
* INC # G1: 1,4 => UNS
* INC # H1: 3,9 => UNS
* DIS # A5: 3,9 => CTR => A5: 5,6
* INC # A5: 5,6 => UNS
* PRF # A6: 3,9 => SOL
* INC # A6: 2,6,8 => UNS
* DIS # A8: 3,9 => CTR => A8: 1,2,6
* INC # A8: 1,2,6 => UNS
* DIS # D6: 4,8 => CTR => D6: 6
* INC # D6: 6 => UNS
* INC # E6: 4,8 => UNS
* PRF # C4: 4,8 => SOL
* DIS # C4: 2,5,9 => CTR => C4: 4,8
* INC # I5: 4,9 => UNS
* INC # I6: 4,9 => UNS
* DIS # B4: 4,9 => CTR => B4: 2
* INC # B4: 2 => UNS
* DIS # C4: 4,9 => CTR => C4: 2,5,8
* INC # C4: 2,5,8 => UNS
* DIS # F4: 4,9 => CTR => F4: 2,5
* INC # F4: 2,5 => UNS
* DIS # E9: 2,8 => CTR => E9: 1,4,5,6
* PRF # E9: 1,4,5,6 => SOL
* CNT  28 HDP CHAINS /  28 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 3,9 => UNS
* DIS # B3: 3,9 => CTR => B3: 1,2,4,6
* INC B3: 1,2,4,6 # C3: 3,9 => UNS
* DIS B3: 1,2,4,6 # G1: 3,9 => CTR => G1: 1,4
* INC B3: 1,2,4,6 + G1: 1,4 # H1: 3,9 => UNS
* INC B3: 1,2,4,6 + G1: 1,4 # H1: 3,9 => UNS
* INC B3: 1,2,4,6 + G1: 1,4 # H1: 4 => UNS
* DIS B3: 1,2,4,6 + G1: 1,4 # A5: 3,9 => CTR => A5: 5,6
* PRF B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 # A6: 3,9 => SOL
* STA B3: 1,2,4,6 + G1: 1,4 + A5: 5,6 + A6: 3,9
* CNT   9 HDP CHAINS /   9 HYP OPENED