Analysis of xx-top500-138-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 18.4.........9.6..3.........7...3.4...9.2...........1.6....1......5..9........2.. initial

Autosolve

position: 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..3.5.29..9..3..2.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C2: 5,7 => CTR => C2: 4
* PRF # C2: 4 => SOL
* PRF # C2: 4,5 => SOL
* DIS # C2: 7 => CTR => C2: 4,5
* DIS # G6: 5,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # I5: 5,7 => CTR => I5: 6
* DIS # I9: 5,7 => CTR => I9: 1,6,8
* DIS # A6: 5,8 => CTR => A6: 4
* DIS # C9: 5,8 => CTR => C9: 1,4,7
* PRF # A5: 4,5 => SOL
* DIS # A5: 8 => CTR => A5: 4,5
* DIS # G6: 5 => CTR => G6: 7,8
* DIS # A6: 8 => CTR => A6: 4,5
* PRF # G6: 5,8 => SOL
* DIS # G6: 7 => CTR => G6: 5,8
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # C8: 7,8 => SOL
* DIS # C9: 7,8 => CTR => C9: 1,4,5
* DIS # E8: 7,8 => CTR => E8: 4,6
* DIS # I8: 7,8 => CTR => I8: 1,6
* DIS # C9: 4,5 => CTR => C9: 1,7,8
* DIS # E8: 7,8 => CTR => E8: 4,6
* DIS # E9: 7,8 => CTR => E9: 4,6
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # I7: 7,8 => SOL
* DIS # I7: 5 => CTR => I7: 7,8
* DIS # E9: 4,7 => CTR => E9: 6,8
* DIS # C9: 4,7 => CTR => C9: 1,5,8
* DIS # I8: 6,7 => CTR => I8: 1,8
* DIS # H9: 6,7 => CTR => H9: 5
* PRF # H9: 5 => SOL
* DIS # I9: 6,7 => CTR => I9: 1,5,8
* DIS # E8: 6,7 => CTR => E8: 4,8
* PRF # H5: 6,7 => SOL
* DIS # H5: 5 => CTR => H5: 6,7
* CNT  38 HDP CHAINS /  60 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 # C2: 5,7 => CTR => C2: 4
* PRF C2: 4 => SOL
* STA C2: 4
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

18.4.........9.6..3.........7...3.4...9.2...........1.6....1......5..9........2.. initial
182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..3.5.29..9..3..2.. autosolve
182436795754198623396275184278613549519824376463759812625981437837542961941367258 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
A2: 5,7
B2: 4,5
E3: 5,7
F3: 5,7
G1: 5,7
I1: 5,7
C4: 5,8
D5: 7,8
F5: 4,5
D6: 7,8
E6: 4,5
G4: 5,8
A8: 7,8
B9: 4,5
E7: 7,8
F9: 4,7
H8: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C8,C9: 1.. / C8 = 1  =>  0 pairs (X) / C9 = 1  => 17 pairs (_)
I8,I9: 1.. / I8 = 1  => 17 pairs (_) / I9 = 1  =>  0 pairs (X)
C8,I8: 1.. / C8 = 1  =>  0 pairs (X) / I8 = 1  => 17 pairs (_)
C9,I9: 1.. / C9 = 1  => 17 pairs (_) / I9 = 1  =>  0 pairs (X)
B2,C2: 4.. / B2 = 4  =>  0 pairs (X) / C2 = 4  =>  0 pairs (_)
A5,A6: 4.. / A5 = 4  =>  0 pairs (X) / A6 = 4  => 22 pairs (_)
F5,E6: 4.. / F5 = 4  => 22 pairs (_) / E6 = 4  =>  0 pairs (X)
A5,F5: 4.. / A5 = 4  =>  0 pairs (X) / F5 = 4  => 22 pairs (_)
A6,E6: 4.. / A6 = 4  => 22 pairs (_) / E6 = 4  =>  0 pairs (X)
C8,E8: 4.. / C8 = 4  =>  0 pairs (X) / E8 = 4  =>  0 pairs (_)
B2,B9: 4.. / B2 = 4  =>  0 pairs (X) / B9 = 4  =>  0 pairs (_)
F5,F9: 4.. / F5 = 4  => 22 pairs (_) / F9 = 4  =>  0 pairs (X)
E3,F3: 5.. / E3 = 5  =>  0 pairs (X) / F3 = 5  => 22 pairs (_)
G1,I1: 5.. / G1 = 5  =>  0 pairs (X) / I1 = 5  =>  0 pairs (_)
F5,E6: 5.. / F5 = 5  =>  0 pairs (X) / E6 = 5  => 22 pairs (_)
C4,G4: 5.. / C4 = 5  =>  0 pairs (X) / G4 = 5  =>  0 pairs (_)
C7,I7: 5.. / C7 = 5  =>  0 pairs (*) / I7 = 5  =>  0 pairs (X)
B2,B9: 5.. / B2 = 5  =>  0 pairs (*) / B9 = 5  =>  0 pairs (X)
E3,E6: 5.. / E3 = 5  =>  0 pairs (X) / E6 = 5  => 22 pairs (_)
F3,F5: 5.. / F3 = 5  => 22 pairs (_) / F5 = 5  =>  0 pairs (X)
H5,H9: 5.. / H5 = 5  =>  0 pairs (X) / H9 = 5  =>  0 pairs (_)
H5,I5: 6.. / H5 = 6  =>  0 pairs (X) / I5 = 6  => 18 pairs (_)
E8,E9: 6.. / E8 = 6  =>  0 pairs (X) / E9 = 6  => 20 pairs (_)
A2,C2: 7.. / A2 = 7  =>  0 pairs (*) / C2 = 7  =>  0 pairs (X)
E3,F3: 7.. / E3 = 7  => 22 pairs (_) / F3 = 7  =>  0 pairs (X)
G1,I1: 7.. / G1 = 7  =>  0 pairs (*) / I1 = 7  =>  0 pairs (X)
D5,D6: 7.. / D5 = 7  =>  0 pairs (X) / D6 = 7  =>  0 pairs (_)
D6,G6: 7.. / D6 = 7  =>  0 pairs (*) / G6 = 7  =>  0 pairs (X)
A2,A8: 7.. / A2 = 7  =>  0 pairs (*) / A8 = 7  =>  0 pairs (X)
F3,F9: 7.. / F3 = 7  =>  0 pairs (X) / F9 = 7  => 22 pairs (_)
G1,G6: 7.. / G1 = 7  =>  0 pairs (*) / G6 = 7  =>  0 pairs (X)
D5,D6: 8.. / D5 = 8  =>  0 pairs (*) / D6 = 8  =>  0 pairs (X)
G4,G6: 8.. / G4 = 8  =>  0 pairs (X) / G6 = 8  =>  0 pairs (_)
C4,G4: 8.. / C4 = 8  =>  0 pairs (*) / G4 = 8  =>  0 pairs (X)
A5,D5: 8.. / A5 = 8  =>  0 pairs (X) / D5 = 8  =>  0 pairs (_)
* DURATION: 0:01:00.578250  START: 07:27:09.803009  END: 07:28:10.381259 2017-05-04
* CP COUNT: (35)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B2,B9,C4,D5,D6,E3,E6,E7,F3,F5,F9,G1,G4,H8,I1)
* 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..3.5.29..9..3..2..
* PAIR A2: 5,7 BLK 1
C2: 5,7,4                                # reduction candidate for 5,7
C2: 5,7 => CTR
* 182436597547198623396275184275613849.197243564638597126289.1435.3.5.29..95.3..2..
C2: 4 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
* PAIR B2: 4,5 BLK 1
C2: 4,5,7                                # reduction candidate for 4,5
C2: 4,5 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
C2: 7 => CTR
* 182436.9.5471986233962.7184275613849.19.253...63..9.1262.9.143.73.5.296.95.36.27.
* PAIR G1: 5,7 COL G
G6: 5,7,8                                # reduction candidate for 5,7
G6: 5,7 => CTR
* 1824365975471986233962..184275613849.19.2.356.63.59712628971435.3.5.29..95.3..2..
G6: 8 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
* PAIR I1: 5,7 COL I
I5: 5,7,6                                # reduction candidate for 5,7
I5: 5,7 => CTR
* 182436.9.7541986233962..18427.613.49.19.2.36..63..9.1262597143883154297.9..3..25.
I5: 6                                    # 18 pairs
I7: 5,7,8                                # reduction candidate for 5,7
I7: 5,7                                  # 21 pairs
I9: 5,7,1,6,8                            # reduction candidate for 5,7
I9: 5,7 => CTR
* 182436.9....1986233962..18427.613.49.19.2.356.63.5971262.97143..3.5.29.19.138.26.
I9: 1,6,8                                # 17 pairs
* PAIR C4: 5,8 BLK 4
A5: 5,8,4                                # reduction candidate for 5,8
A5: 5,8                                  # 22 pairs
A6: 5,8,4                                # reduction candidate for 5,8
A6: 5,8 => CTR
* 182436.9....1986233962..18427.613.494198253...63749.1262.9.143..345.29.19513.42..
A6: 4                                    # 22 pairs
* PAIR C4: 5,8 COL C
C7: 5,8,7                                # reduction candidate for 5,8
C7: 5,8                                  # 19 pairs
C9: 5,8,1,4,7                            # reduction candidate for 5,8
C9: 5,8 => CTR
* 182436.9..5419862339627518427.613.49.19.243..463.59.1262.9.143..315429..94.367251
C9: 1,4,7                                # 17 pairs
* PAIR F5: 4,5 ROW 5
A5: 4,5,8                                # reduction candidate for 4,5
A5: 4,5 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
A5: 8 => CTR
* 182436.9....1986233962..18427.613.498197243..46385971262.9.143.73.5.296.9..36725.
* PAIR D6: 7,8 ROW 6
G6: 7,8,5                                # reduction candidate for 7,8
G6: 5 => CTR
* 182436795...1986233962..18427.613849.19.2.3...637.95126259.143..3.5.29..9..3..2..
G6: 7,8                                  # 19 pairs
* PAIR E6: 4,5 ROW 6
A6: 4,5,8                                # reduction candidate for 4,5
A6: 8 => CTR
* 182436.9....1986233962..18427.613.494198253..86374951262.9.143.7345.296195136427.
A6: 4,5                                  # 19 pairs
* PAIR G4: 5,8 BLK 6
G6: 5,8,7                                # reduction candidate for 5,8
G6: 5,8 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
G6: 7 => CTR
* 1824365975471986233962751842756138498197243564638597126289.1435.3.5.29..95.3..2..
* PAIR A8: 7,8 BLK 7
C7: 7,8,5                                # reduction candidate for 7,8
C7: 7,8 => CTR
* 182436597547198623396275184275613849.197243564638597126289.1435.3.5.29..95.3..2..
C7: 5 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
C8: 7,8,1,4                              # reduction candidate for 7,8
C8: 7,8 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
C8: 1,4                                  # 18 pairs
C9: 7,8,1,4,5                            # reduction candidate for 7,8
C9: 7,8 => CTR
* 182436.9..5419862339627518427.613.49.19.243..463.59.1262.9.143..315429..94.367251
C9: 1,4,5                                # 17 pairs
* PAIR A8: 7,8 ROW 8
E8: 7,8,4,6                              # reduction candidate for 7,8
E8: 7,8 => CTR
* 182436.9..4.1986233962.718427.613.494198253...63..9.1262.9.143..345.29.1951364278
E8: 4,6                                  # 18 pairs
I8: 7,8,1,6                              # reduction candidate for 7,8
I8: 7,8 => CTR
* 182436.9..5419862339627518427.613.49.19.2437646375981262.9.143..3154296.9..367251
I8: 1,6                                  # 18 pairs
* PAIR B9: 4,5 BLK 7
C9: 4,5,1,7,8                            # reduction candidate for 4,5
C9: 4,5 => CTR
* 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..315429..9..3672..
C9: 1,7,8                                # 17 pairs
* PAIR E7: 7,8 BLK 8
E8: 7,8,4,6                              # reduction candidate for 7,8
E8: 7,8 => CTR
* 182436.9..4.1986233962.718427.613.494198253...63..9.1262.9.143..345.29.1951364278
E8: 4,6                                  # 18 pairs
E9: 7,8,4,6                              # reduction candidate for 7,8
E9: 7,8 => CTR
* 182436.9.7451986233962.7184278613549419825367563749812627981435.3.56297.9..3.42..
E9: 4,6                                  # 20 pairs
* PAIR E7: 7,8 ROW 7
C7: 7,8,5                                # reduction candidate for 7,8
C7: 7,8 => CTR
* 182436597547198623396275184275613849.197243564638597126289.1435.3.5.29..95.3..2..
C7: 5 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
I7: 7,8,5                                # reduction candidate for 7,8
I7: 7,8 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
I7: 5 => CTR
* 182436597547198623396275184275613849.197243564638597126289.1435.3.5.29..95.3..2..
* PAIR F9: 4,7 BLK 8
E8: 4,7,6,8                              # reduction candidate for 4,7
E8: 4,7                                  # 23 pairs
E9: 4,7,6,8                              # reduction candidate for 4,7
E9: 4,7 => CTR
* 1824365977451986233962..18427.613.49.19.2.3...63..9.1262.9814358345629719513..268
E9: 6,8                                  # 18 pairs
* PAIR F9: 4,7 ROW 9
C9: 4,7,1,5,8                            # reduction candidate for 4,7
C9: 4,7 => CTR
* 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..315429..9..3672..
C9: 1,5,8                                # 17 pairs
* PAIR H8: 6,7 BLK 9
I8: 6,7,1,8                              # reduction candidate for 6,7
I8: 6,7 => CTR
* 182436.9..5419862339627518427.613.49.19.243..463.59.1262.9.143..315429..9..367251
I8: 1,8                                  # 18 pairs
H9: 6,7,5                                # reduction candidate for 6,7
H9: 6,7 => CTR
* 182436597547198623396275184275613849.197243564638597126289.143..3.5.29..9..3..2..
H9: 5 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
I9: 6,7,1,5,8                            # reduction candidate for 6,7
I9: 6,7 => CTR
* 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.971438.3.5629719.138425.
I9: 1,5,8                                # 17 pairs
* PAIR H8: 6,7 ROW 8
E8: 6,7,4,8                              # reduction candidate for 6,7
E8: 6,7 => CTR
* 182436.9..4.1986233962..18427.613.49.19.2.356.63.5971262.9.14358345.29.1951347268
E8: 4,8                                  # 21 pairs
* PAIR H8: 6,7 COL H
H5: 6,7,5                                # reduction candidate for 6,7
H5: 6,7 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
H5: 5 => CTR
* 182436597547198623396275184275613849.197243564638597126289.143..3.5.29..9..3..2..
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-138-base-pr-000.dot
* REASONING
* DIS # C2: 5,7 => CTR => C2: 4
* PRF # C2: 4 => SOL
* PRF # C2: 4,5 => SOL
* DIS # C2: 7 => CTR => C2: 4,5
* DIS # G6: 5,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # I5: 5,7 => CTR => I5: 6
* DIS # I9: 5,7 => CTR => I9: 1,6,8
* DIS # A6: 5,8 => CTR => A6: 4
* DIS # C9: 5,8 => CTR => C9: 1,4,7
* PRF # A5: 4,5 => SOL
* DIS # A5: 8 => CTR => A5: 4,5
* DIS # G6: 5 => CTR => G6: 7,8
* DIS # A6: 8 => CTR => A6: 4,5
* PRF # G6: 5,8 => SOL
* DIS # G6: 7 => CTR => G6: 5,8
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # C8: 7,8 => SOL
* DIS # C9: 7,8 => CTR => C9: 1,4,5
* DIS # E8: 7,8 => CTR => E8: 4,6
* DIS # I8: 7,8 => CTR => I8: 1,6
* DIS # C9: 4,5 => CTR => C9: 1,7,8
* DIS # E8: 7,8 => CTR => E8: 4,6
* DIS # E9: 7,8 => CTR => E9: 4,6
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # I7: 7,8 => SOL
* DIS # I7: 5 => CTR => I7: 7,8
* DIS # E9: 4,7 => CTR => E9: 6,8
* DIS # C9: 4,7 => CTR => C9: 1,5,8
* DIS # I8: 6,7 => CTR => I8: 1,8
* DIS # H9: 6,7 => CTR => H9: 5
* PRF # H9: 5 => SOL
* DIS # I9: 6,7 => CTR => I9: 1,5,8
* DIS # E8: 6,7 => CTR => E8: 4,8
* PRF # H5: 6,7 => SOL
* DIS # H5: 5 => CTR => H5: 6,7
* CNT  38 HDP CHAINS /  60 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B2,B9,C4,D5,D6,E3,E6,E7,F3,F5,F9,G1,G4,H8,I1)
* 182436.9....1986233962..18427.613.49.19.2.3...63..9.1262.9.143..3.5.29..9..3..2..
* PAIR A2: 5,7 BLK 1
C2: 5,7,4                                # reduction candidate for 5,7
C2: 5,7 => CTR
* 182436597547198623396275184275613849.197243564638597126289.1435.3.5.29..95.3..2..
C2: 4 => SOLVED
* 182436795754198623396275184278613549519824376463759812625981437837542961941367258
* DURATION: 0:00:03.082531  START: 07:29:09.151828  END: 07:29:12.234359 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-138-base-pr-001.dot
* REASONING
* DIS # C2: 5,7 => CTR => C2: 4
* PRF C2: 4 => SOL
* STA C2: 4
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 138

solution: 182436795754198623396275184278613549519824376463759812625981437837542961941367258
info: 1813     FNBTWY   S8.f     26635

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

Solution

position: 182436795754198623396275184278613549519824376463759812625981437837542961941367258 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 # C2: 5,7 => CTR => C2: 4
* PRF # C2: 4 => SOL
* PRF # C2: 4,5 => SOL
* DIS # C2: 7 => CTR => C2: 4,5
* DIS # G6: 5,7 => CTR => G6: 8
* PRF # G6: 8 => SOL
* DIS # I5: 5,7 => CTR => I5: 6
* INC # I5: 6 => UNS
* INC # I7: 5,7 => UNS
* DIS # I9: 5,7 => CTR => I9: 1,6,8
* INC # I9: 1,6,8 => UNS
* INC # A5: 5,8 => UNS
* DIS # A6: 5,8 => CTR => A6: 4
* INC # A6: 4 => UNS
* INC # C7: 5,8 => UNS
* DIS # C9: 5,8 => CTR => C9: 1,4,7
* INC # C9: 1,4,7 => UNS
* PRF # A5: 4,5 => SOL
* DIS # A5: 8 => CTR => A5: 4,5
* INC # G6: 7,8 => UNS
* DIS # G6: 5 => CTR => G6: 7,8
* INC # A6: 4,5 => UNS
* DIS # A6: 8 => CTR => A6: 4,5
* PRF # G6: 5,8 => SOL
* DIS # G6: 7 => CTR => G6: 5,8
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # C8: 7,8 => SOL
* INC # C8: 1,4 => UNS
* DIS # C9: 7,8 => CTR => C9: 1,4,5
* INC # C9: 1,4,5 => UNS
* DIS # E8: 7,8 => CTR => E8: 4,6
* INC # E8: 4,6 => UNS
* DIS # I8: 7,8 => CTR => I8: 1,6
* INC # I8: 1,6 => UNS
* DIS # C9: 4,5 => CTR => C9: 1,7,8
* INC # C9: 1,7,8 => UNS
* DIS # E8: 7,8 => CTR => E8: 4,6
* INC # E8: 4,6 => UNS
* DIS # E9: 7,8 => CTR => E9: 4,6
* INC # E9: 4,6 => UNS
* DIS # C7: 7,8 => CTR => C7: 5
* PRF # C7: 5 => SOL
* PRF # I7: 7,8 => SOL
* DIS # I7: 5 => CTR => I7: 7,8
* INC # E8: 4,7 => UNS
* DIS # E9: 4,7 => CTR => E9: 6,8
* INC # E9: 6,8 => UNS
* DIS # C9: 4,7 => CTR => C9: 1,5,8
* INC # C9: 1,5,8 => UNS
* DIS # I8: 6,7 => CTR => I8: 1,8
* INC # I8: 1,8 => UNS
* DIS # H9: 6,7 => CTR => H9: 5
* PRF # H9: 5 => SOL
* DIS # I9: 6,7 => CTR => I9: 1,5,8
* INC # I9: 1,5,8 => UNS
* DIS # E8: 6,7 => CTR => E8: 4,8
* INC # E8: 4,8 => UNS
* PRF # H5: 6,7 => SOL
* DIS # H5: 5 => CTR => H5: 6,7
* CNT  60 HDP CHAINS /  60 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # C2: 5,7 => CTR => C2: 4
* PRF C2: 4 => SOL
* STA C2: 4
* CNT   2 HDP CHAINS /   1 HYP OPENED