Analysis of xx-top500-369-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...6..1..83.......5........2.....43....1..2.....75.....71..........8..5.....3.... initial

Autosolve

position: 7.46.518383..1.5.751.378...2578..431..81432751437528...715..3.83...8175..85.37.1. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # C2: 2,9 => SOL
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* DIS # D2: 4 => CTR => D2: 2,9
* DIS # E7: 6 => CTR => E7: 2,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* DIS # F7: 4,9 => CTR => F7: 6
* DIS # H3: 6,9 => CTR => H3: 2,4
* DIS # I3: 6,9 => CTR => I3: 2,4
* DIS # C3: 2 => CTR => C3: 6,9
* PRF # A9: 4 => SOL
* PRF # B8: 6,9 => SOL
* DIS # B8: 2 => CTR => B8: 6,9
* DIS # E7: 6,9 => CTR => E7: 2
* PRF # E7: 2 => SOL
* DIS # F7: 4 => CTR => F7: 6,9
* DIS # H3: 6,9 => CTR => H3: 2,4
* DIS # I3: 6,9 => CTR => I3: 2,4
* DIS # I9: 6,9 => CTR => I9: 2,4
* PRF # A9: 4,9 => SOL
* DIS # A9: 6 => CTR => A9: 4,9
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # H7: 4,9 => SOL
* DIS # H7: 2 => CTR => H7: 4,9
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* PRF # C2: 2,9 => SOL
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # D9: 4,9 => SOL
* DIS # D9: 2 => CTR => D9: 4,9
* PRF # I8: 4,9 => SOL
* DIS # I8: 6 => CTR => I8: 4,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* DIS # I9: 6,9 => CTR => I9: 2,4
* PRF # A9: 4 => SOL
* CNT  37 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:

* PRF # C2: 2,9 => SOL
* STA C2: 2,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

...6..1..83.......5........2.....43....1..2.....75.....71..........8..5.....3.... initial
7.46.518383..1.5.751.378...2578..431..81432751437528...715..3.83...8175..85.37.1. autosolve
724695183839214567516378924257869431698143275143752896971526348362481759485937612 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
B1: 2,9
E1: 2,9
F2: 4,9
G3: 6,9
A5: 6,9
B5: 6,9
E4: 6,9
F4: 6,9
H6: 6,9
I6: 6,9
A7: 4,9
C8: 2,9
D8: 4,9
G9: 6,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E1,D2: 2.. / E1 = 2  =>  0 pairs (X) / D2 = 2  =>  0 pairs (_)
B8,C8: 2.. / B8 = 2  =>  0 pairs (X) / C8 = 2  =>  0 pairs (_)
E7,D9: 2.. / E7 = 2  =>  0 pairs (*) / D9 = 2  =>  0 pairs (X)
H7,I9: 2.. / H7 = 2  =>  0 pairs (X) / I9 = 2  =>  0 pairs (_)
B1,E1: 2.. / B1 = 2  =>  0 pairs (*) / E1 = 2  =>  0 pairs (X)
E7,H7: 2.. / E7 = 2  =>  0 pairs (*) / H7 = 2  =>  0 pairs (X)
D9,I9: 2.. / D9 = 2  =>  0 pairs (X) / I9 = 2  =>  0 pairs (_)
B1,B8: 2.. / B1 = 2  =>  0 pairs (*) / B8 = 2  =>  0 pairs (X)
D2,D9: 2.. / D2 = 2  =>  0 pairs (*) / D9 = 2  =>  0 pairs (X)
E1,E7: 2.. / E1 = 2  =>  0 pairs (X) / E7 = 2  =>  0 pairs (_)
I3,I9: 2.. / I3 = 2  =>  0 pairs (X) / I9 = 2  =>  0 pairs (_)
D2,F2: 4.. / D2 = 4  =>  0 pairs (X) / F2 = 4  => 15 pairs (_)
H3,I3: 4.. / H3 = 4  => 15 pairs (_) / I3 = 4  =>  0 pairs (*)
A7,A9: 4.. / A7 = 4  => 18 pairs (_) / A9 = 4  =>  0 pairs (*)
D8,I8: 4.. / D8 = 4  => 19 pairs (_) / I8 = 4  =>  0 pairs (X)
F2,F7: 4.. / F2 = 4  => 15 pairs (_) / F7 = 4  =>  0 pairs (X)
H3,H7: 4.. / H3 = 4  => 15 pairs (_) / H7 = 4  =>  0 pairs (*)
C2,C3: 6.. / C2 = 6  => 16 pairs (_) / C3 = 6  =>  0 pairs (*)
A5,B5: 6.. / A5 = 6  =>  0 pairs (*) / B5 = 6  =>  0 pairs (X)
E4,F4: 6.. / E4 = 6  => 13 pairs (_) / F4 = 6  =>  0 pairs (X)
H6,I6: 6.. / H6 = 6  => 15 pairs (_) / I6 = 6  =>  0 pairs (*)
B8,A9: 6.. / B8 = 6  =>  0 pairs (*) / A9 = 6  =>  0 pairs (X)
E7,F7: 6.. / E7 = 6  =>  0 pairs (X) / F7 = 6  => 13 pairs (_)
C2,H2: 6.. / C2 = 6  => 16 pairs (_) / H2 = 6  =>  0 pairs (*)
B8,I8: 6.. / B8 = 6  =>  0 pairs (*) / I8 = 6  =>  0 pairs (X)
A5,A9: 6.. / A5 = 6  =>  0 pairs (*) / A9 = 6  =>  0 pairs (X)
B5,B8: 6.. / B5 = 6  =>  0 pairs (X) / B8 = 6  =>  0 pairs (_)
E4,E7: 6.. / E4 = 6  => 13 pairs (_) / E7 = 6  =>  0 pairs (X)
F4,F7: 6.. / F4 = 6  =>  0 pairs (X) / F7 = 6  => 13 pairs (_)
G3,G9: 6.. / G3 = 6  => 17 pairs (_) / G9 = 6  =>  0 pairs (*)
A5,B5: 9.. / A5 = 9  =>  0 pairs (X) / B5 = 9  =>  0 pairs (_)
E4,F4: 9.. / E4 = 9  =>  0 pairs (X) / F4 = 9  => 13 pairs (_)
H6,I6: 9.. / H6 = 9  =>  0 pairs (*) / I6 = 9  =>  0 pairs (X)
B1,E1: 9.. / B1 = 9  =>  0 pairs (X) / E1 = 9  =>  0 pairs (_)
G3,G9: 9.. / G3 = 9  =>  0 pairs (*) / G9 = 9  =>  0 pairs (X)
* DURATION: 0:01:04.093153  START: 15:27:07.052129  END: 15:28:11.145282 2017-05-04
* CP COUNT: (35)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,B1,B5,C8,D8,E1,E4,F2,F4,G3,G9,H6,I6)
* 7.46.518383..1.5.751.378...2578..431..81432751437528...715..3.83...8175..85.37.1.
* PAIR B1: 2,9 BLK 1
C2: 2,9,6                                # reduction candidate for 2,9
C2: 2,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
C2: 6                                    # 16 pairs
C3: 2,9,6                                # reduction candidate for 2,9
C3: 2,9                                  # 16 pairs
* PAIR B1: 2,9 COL B
B8: 2,9,6                                # reduction candidate for 2,9
B8: 2,9 => CTR
* 7.46.518383..1.5.751.3786..2578..4319681432751437528694715..3283..481756685237914
B8: 6 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* PAIR E1: 2,9 BLK 2
D2: 2,9,4                                # reduction candidate for 2,9
D2: 4 => CTR
* 7.462518383.4195.751.378...257896431..81432751437528...71564328329.8175..85.37.1.
D2: 2,9                                  # 15 pairs
* PAIR E1: 2,9 COL E
E7: 2,9,6                                # reduction candidate for 2,9
E7: 6 => CTR
* 79462518383291456751.378...257896431..81432751437528...7156.328329481756685237914
E7: 2,9                                  # 13 pairs
* PAIR F2: 4,9 BLK 2
D2: 4,9,2                                # reduction candidate for 4,9
D2: 4,9 => CTR
* 79462518383291456751.378...2578..431..81432751437528...715..328329481756685237914
D2: 2 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* PAIR F2: 4,9 COL F
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 7.4625183832.1.567516378942257896431..8143275143752896.7156.3283...8175..85237.1.
F7: 6                                    # 13 pairs
* PAIR G3: 6,9 BLK 3
H2: 6,9,2                                # reduction candidate for 6,9
H2: 6,9                                  # 19 pairs
H3: 6,9,2,4                              # reduction candidate for 6,9
H3: 6,9 => CTR
* 7.46.518383.2145.7512378..42578..4316981432751437528...715..3483..48175.485.37.12
H3: 2,4                                  # 15 pairs
I3: 6,9,2,4                              # reduction candidate for 6,9
I3: 6,9 => CTR
* 7.46.518383.2145.7512378.4.2578..431..81432751437528..471526398329.8175..85.37.12
I3: 2,4                                  # 15 pairs
* PAIR G3: 6,9 ROW 3
C3: 6,9,2                                # reduction candidate for 6,9
C3: 2 => CTR
* 7.46.5183836.1.5.7512378...2578..431..81432751437528...715..3.8329481756685.3791.
C3: 6,9                                  # 19 pairs
* PAIR A5: 6,9 COL A
A9: 6,9,4                                # reduction candidate for 6,9
A9: 4 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
A9: 6,9                                  # 18 pairs
* PAIR B5: 6,9 COL B
B8: 6,9,2                                # reduction candidate for 6,9
B8: 6,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
B8: 2 => CTR
* 79462518383.9145.751.37864.2578..431.681432751437528...715..3.8329481756685.37914
* PAIR E4: 6,9 COL E
E7: 6,9,2                                # reduction candidate for 6,9
E7: 6,9 => CTR
* 79462518383291456751.378...2578..431..81432751437528...715..328329481756685237914
E7: 2 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* PAIR F4: 6,9 COL F
F7: 6,9,4                                # reduction candidate for 6,9
F7: 4 => CTR
* 7.4625183832.1.5.751.378...2578.6431..81432751437528...715643283..981754485237.1.
F7: 6,9                                  # 15 pairs
* PAIR H6: 6,9 COL H
H2: 6,9,2                                # reduction candidate for 6,9
H2: 6,9                                  # 19 pairs
H3: 6,9,2,4                              # reduction candidate for 6,9
H3: 6,9 => CTR
* 7.46.518383.2145.7512378..42578..4316981432751437528...715..3483..48175.485.37.12
H3: 2,4                                  # 15 pairs
* PAIR I6: 6,9 COL I
I3: 6,9,2,4                              # reduction candidate for 6,9
I3: 6,9 => CTR
* 7.46.518383.2145.7512378.4.2578..431..81432751437528..471526398329.8175..85.37.12
I3: 2,4                                  # 15 pairs
I8: 6,9,4                                # reduction candidate for 6,9
I8: 6,9                                  # 19 pairs
I9: 6,9,2,4                              # reduction candidate for 6,9
I9: 6,9 => CTR
* 7.4625183832419567516378942257896431..81432751437528969715..3283...81754.85237.1.
I9: 2,4                                  # 15 pairs
* PAIR A7: 4,9 BLK 7
A9: 4,9,6                                # reduction candidate for 4,9
A9: 4,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
A9: 6 => CTR
* 7.46.518383..145.751.37864.2578..4319681432751437528694715..3283...81756685237914
* PAIR A7: 4,9 ROW 7
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 7.4625183832.1.567516378942257896431..8143275143752896.7156.3283...8175..85237.1.
F7: 6                                    # 13 pairs
H7: 4,9,2                                # reduction candidate for 4,9
H7: 4,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
H7: 2 => CTR
* 7.4625183832.1.5675163789422578..431..8143275143752896.715..3283...8175..85237.1.
* PAIR C8: 2,9 BLK 7
B8: 2,9,6                                # reduction candidate for 2,9
B8: 2,9 => CTR
* 7.46.518383..1.5.751.3786..2578..4319681432751437528694715..3283..481756685237914
B8: 6 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* PAIR C8: 2,9 COL C
C2: 2,9,6                                # reduction candidate for 2,9
C2: 2,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
C2: 6                                    # 16 pairs
C3: 2,9,6                                # reduction candidate for 2,9
C3: 2,9                                  # 16 pairs
* PAIR D8: 4,9 BLK 8
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 7.4625183832.1.567516378942257896431..8143275143752896.7156.3283...8175..85237.1.
F7: 6                                    # 13 pairs
D9: 4,9,2                                # reduction candidate for 4,9
D9: 4,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
D9: 2 => CTR
* 7.462518383..1.5.751.378..22578..431..81432751437528...715..328329481756685237914
* PAIR D8: 4,9 ROW 8
I8: 4,9,6                                # reduction candidate for 4,9
I8: 4,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
I8: 6 => CTR
* 7.46.518383.9145.751.37864.2578..431..81432751437528...715..3.83..481756685.37914
* PAIR D8: 4,9 COL D
D2: 4,9,2                                # reduction candidate for 4,9
D2: 4,9 => CTR
* 79462518383291456751.378...2578..431..81432751437528...715..328329481756685237914
D2: 2 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* PAIR G9: 6,9 BLK 9
I8: 6,9,4                                # reduction candidate for 6,9
I8: 6,9                                  # 19 pairs
I9: 6,9,2,4                              # reduction candidate for 6,9
I9: 6,9 => CTR
* 7.4625183832419567516378942257896431..81432751437528969715..3283...81754.85237.1.
I9: 2,4                                  # 15 pairs
* PAIR G9: 6,9 ROW 9
A9: 6,9,4                                # reduction candidate for 6,9
A9: 4 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
A9: 6,9                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-369-base-pr-000.dot
* REASONING
* PRF # C2: 2,9 => SOL
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* DIS # D2: 4 => CTR => D2: 2,9
* DIS # E7: 6 => CTR => E7: 2,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* DIS # F7: 4,9 => CTR => F7: 6
* DIS # H3: 6,9 => CTR => H3: 2,4
* DIS # I3: 6,9 => CTR => I3: 2,4
* DIS # C3: 2 => CTR => C3: 6,9
* PRF # A9: 4 => SOL
* PRF # B8: 6,9 => SOL
* DIS # B8: 2 => CTR => B8: 6,9
* DIS # E7: 6,9 => CTR => E7: 2
* PRF # E7: 2 => SOL
* DIS # F7: 4 => CTR => F7: 6,9
* DIS # H3: 6,9 => CTR => H3: 2,4
* DIS # I3: 6,9 => CTR => I3: 2,4
* DIS # I9: 6,9 => CTR => I9: 2,4
* PRF # A9: 4,9 => SOL
* DIS # A9: 6 => CTR => A9: 4,9
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # H7: 4,9 => SOL
* DIS # H7: 2 => CTR => H7: 4,9
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* PRF # C2: 2,9 => SOL
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # D9: 4,9 => SOL
* DIS # D9: 2 => CTR => D9: 4,9
* PRF # I8: 4,9 => SOL
* DIS # I8: 6 => CTR => I8: 4,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* DIS # I9: 6,9 => CTR => I9: 2,4
* PRF # A9: 4 => SOL
* CNT  37 HDP CHAINS /  60 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A7,B1,B5,C8,D8,E1,E4,F2,F4,G3,G9,H6,I6)
* 7.46.518383..1.5.751.378...2578..431..81432751437528...715..3.83...8175..85.37.1.
* PAIR B1: 2,9 BLK 1
C2: 2,9,6                                # reduction candidate for 2,9
C2: 2,9 => SOLVED
* 724695183839214567516378924257869431698143275143752896971526348362481759485937612
* DURATION: 0:00:02.029309  START: 15:29:14.299371  END: 15:29:16.328680 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-369-base-pr-001.dot
* REASONING
* PRF # C2: 2,9 => SOL
* STA C2: 2,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 369

solution: 724695183839214567516378924257869431698143275143752896971526348362481759485937612
info: 5149     FNBTWXY  S8.f     10517

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

Solution

position: 724695183839214567516378924257869431698143275143752896971526348362481759485937612 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:

* PRF # C2: 2,9 => SOL
* INC # C2: 6 => UNS
* INC # C3: 2,9 => UNS
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* INC # D2: 2,9 => UNS
* DIS # D2: 4 => CTR => D2: 2,9
* INC # E7: 2,9 => UNS
* DIS # E7: 6 => CTR => E7: 2,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* INC # H2: 6,9 => UNS
* DIS # H3: 6,9 => CTR => H3: 2,4
* INC # H3: 2,4 => UNS
* DIS # I3: 6,9 => CTR => I3: 2,4
* INC # I3: 2,4 => UNS
* INC # C3: 6,9 => UNS
* DIS # C3: 2 => CTR => C3: 6,9
* INC # A9: 6,9 => UNS
* PRF # A9: 4 => SOL
* PRF # B8: 6,9 => SOL
* DIS # B8: 2 => CTR => B8: 6,9
* DIS # E7: 6,9 => CTR => E7: 2
* PRF # E7: 2 => SOL
* INC # F7: 6,9 => UNS
* DIS # F7: 4 => CTR => F7: 6,9
* INC # H2: 6,9 => UNS
* DIS # H3: 6,9 => CTR => H3: 2,4
* INC # H3: 2,4 => UNS
* DIS # I3: 6,9 => CTR => I3: 2,4
* INC # I3: 2,4 => UNS
* INC # I8: 6,9 => UNS
* DIS # I9: 6,9 => CTR => I9: 2,4
* INC # I9: 2,4 => UNS
* PRF # A9: 4,9 => SOL
* DIS # A9: 6 => CTR => A9: 4,9
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* PRF # H7: 4,9 => SOL
* DIS # H7: 2 => CTR => H7: 4,9
* DIS # B8: 2,9 => CTR => B8: 6
* PRF # B8: 6 => SOL
* PRF # C2: 2,9 => SOL
* INC # C2: 6 => UNS
* INC # C3: 2,9 => UNS
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* PRF # D9: 4,9 => SOL
* DIS # D9: 2 => CTR => D9: 4,9
* PRF # I8: 4,9 => SOL
* DIS # I8: 6 => CTR => I8: 4,9
* DIS # D2: 4,9 => CTR => D2: 2
* PRF # D2: 2 => SOL
* INC # I8: 6,9 => UNS
* DIS # I9: 6,9 => CTR => I9: 2,4
* INC # I9: 2,4 => UNS
* INC # A9: 6,9 => UNS
* PRF # A9: 4 => SOL
* CNT  60 HDP CHAINS /  60 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # C2: 2,9 => SOL
* STA C2: 2,9
* CNT   1 HDP CHAINS /   1 HYP OPENED