Analysis of xx-top500-405-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .4..5..67...9...4....2.....1..8..3........2...6...........4..5.3.....8..2........ initial

Autosolve

position: .42.5..67...9...42...2.4.3812.8..394......2.6.6..2.7.5....4265.3.46..82.2.6...47. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A5: 8,9 => CTR => A5: 4,5,7
* PRF # A6: 8,9 => SOL
* DIS # A6: 4 => CTR => A6: 8,9
* DIS # A7: 8,9 => CTR => A7: 7
* PRF # A7: 7 => SOL
* PRF # F1: 1,3 => SOL
* DIS # F1: 8 => CTR => F1: 1,3
* DIS # D5: 1,3 => CTR => D5: 4,5,7
* DIS # D6: 1,3 => CTR => D6: 4
* PRF # D6: 4 => SOL
* PRF # D7: 1,3 => SOL
* DIS # D7: 7 => CTR => D7: 1,3
* DIS # D9: 1,3 => CTR => D9: 5
* PRF # D9: 5 => SOL
* PRF # G3: 5 => SOL
* PRF # G3: 1,5 => SOL
* DIS # G3: 9 => CTR => G3: 1,5
* DIS # A5: 5,7 => CTR => A5: 4,8,9
* PRF # A5: 4,8,9 => SOL
* PRF # C5: 5,7 => SOL
* PRF # F4: 5,7 => SOL
* DIS # F4: 6 => CTR => F4: 5,7
* DIS # F4: 6,7 => CTR => F4: 5
* PRF # F4: 5 => SOL
* DIS # E2: 6,7 => CTR => E2: 1,8
* DIS # I7: 1,9 => CTR => I7: 3
* DIS # B8: 1,9 => CTR => B8: 5,7
* DIS # F8: 1,9 => CTR => F8: 5,7
* CNT  28 HDP CHAINS /  43 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 # A5: 8,9 => CTR => A5: 4,5,7
* PRF A5: 4,5,7 # A6: 8,9 => SOL
* STA A5: 4,5,7 + A6: 8,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.4..5..67...9...4....2.....1..8..3........2...6...........4..5.3.....8..2........ initial
.42.5..67...9...42...2.4.3812.8..394......2.6.6..2.7.5....4265.3.46..82.2.6...47. autosolve
842351967573986142691274538127865394435719286968423715789142653354697821216538479 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
A1: 8,9
D1: 1,3
G1: 1,9
G2: 1,5
C4: 5,7
E4: 6,7
H5: 1,8
H6: 1,8
I8: 1,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H5,H6: 1.. / H5 = 1  =>  9 pairs (_) / H6 = 1  =>  9 pairs (_)
B2,C2: 3.. / B2 = 3  =>  9 pairs (_) / C2 = 3  =>  0 pairs (*)
D1,F1: 3.. / D1 = 3  =>  0 pairs (*) / F1 = 3  =>  0 pairs (X)
I7,I9: 3.. / I7 = 3  => 12 pairs (_) / I9 = 3  =>  0 pairs (X)
D7,I7: 3.. / D7 = 3  =>  0 pairs (X) / I7 = 3  => 12 pairs (_)
B2,B5: 3.. / B2 = 3  =>  9 pairs (_) / B5 = 3  =>  0 pairs (*)
E5,E9: 3.. / E5 = 3  => 11 pairs (_) / E9 = 3  =>  0 pairs (*)
A5,A6: 4.. / A5 = 4  =>  0 pairs (*) / A6 = 4  =>  0 pairs (X)
D5,D6: 4.. / D5 = 4  =>  0 pairs (X) / D6 = 4  =>  0 pairs (_)
A5,D5: 4.. / A5 = 4  =>  0 pairs (*) / D5 = 4  =>  0 pairs (X)
A6,D6: 4.. / A6 = 4  =>  0 pairs (X) / D6 = 4  =>  0 pairs (_)
G2,G3: 5.. / G2 = 5  =>  9 pairs (_) / G3 = 5  =>  0 pairs (*)
B8,B9: 5.. / B8 = 5  =>  0 pairs (*) / B9 = 5  =>  0 pairs (X)
C4,F4: 5.. / C4 = 5  =>  0 pairs (X) / F4 = 5  =>  0 pairs (_)
B8,F8: 5.. / B8 = 5  =>  0 pairs (*) / F8 = 5  =>  0 pairs (X)
D5,D9: 5.. / D5 = 5  =>  0 pairs (X) / D9 = 5  =>  0 pairs (_)
A2,A3: 6.. / A2 = 6  =>  0 pairs (X) / A3 = 6  => 10 pairs (_)
E4,F4: 6.. / E4 = 6  =>  0 pairs (*) / F4 = 6  =>  0 pairs (X)
A3,E3: 6.. / A3 = 6  => 10 pairs (_) / E3 = 6  =>  0 pairs (X)
F2,F4: 6.. / F2 = 6  =>  0 pairs (*) / F4 = 6  =>  0 pairs (X)
D5,D7: 7.. / D5 = 7  =>  0 pairs (*) / D7 = 7  =>  0 pairs (X)
H5,H6: 8.. / H5 = 8  =>  9 pairs (_) / H6 = 8  =>  9 pairs (_)
E9,F9: 8.. / E9 = 8  =>  0 pairs (X) / F9 = 8  =>  0 pairs (_)
A1,F1: 8.. / A1 = 8  =>  0 pairs (*) / F1 = 8  =>  0 pairs (X)
E2,E9: 8.. / E2 = 8  =>  0 pairs (*) / E9 = 8  =>  0 pairs (X)
G1,G3: 9.. / G1 = 9  =>  0 pairs (*) / G3 = 9  =>  0 pairs (X)
A1,G1: 9.. / A1 = 9  =>  0 pairs (X) / G1 = 9  =>  0 pairs (_)
* DURATION: 0:00:51.444056  START: 16:40:55.883508  END: 16:41:47.327564 2017-05-04
* CP COUNT: (27)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,C4,D1,E4,G1,G2,H5,H6,I8)
* .42.5..67...9...42...2.4.3812.8..394......2.6.6..2.7.5....4265.3.46..82.2.6...47.
* PAIR A1: 8,9 COL A
A5: 8,9,4,5,7                            # reduction candidate for 8,9
A5: 8,9 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
A5: 4,5,7                                #  9 pairs
A6: 8,9,4                                # reduction candidate for 8,9
A6: 8,9 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
A6: 4 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
A7: 8,9,7                                # reduction candidate for 8,9
A7: 8,9 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
A7: 7 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
* PAIR D1: 1,3 BLK 2
F1: 1,3,8                                # reduction candidate for 1,3
F1: 1,3 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
F1: 8 => CTR
* 942358167.3.9..542...2.493812.8..394....31286863429715789142653354697821216583479
* PAIR D1: 1,3 COL D
D5: 1,3,4,5,7                            # reduction candidate for 1,3
D5: 1,3 => CTR
* .42.5..67...9...42...2.4.3812.8..3944.....2.6.6.42.7.5...7426533746.582.256...47.
D5: 4,5,7                                #  9 pairs
D6: 1,3,4                                # reduction candidate for 1,3
D6: 1,3 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
D6: 4 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
D7: 1,3,7                                # reduction candidate for 1,3
D7: 1,3 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
D7: 7 => CTR
* .42.5..67...9...42...2.4.381258..3944.75..2.6.6.42.7.5...7426533746.582.256...47.
D9: 1,3,5                                # reduction candidate for 1,3
D9: 1,3 => CTR
* .42.5..67...9...42...2.4.381258..3944.75..2.6.6.42.7.5...7426533746.582.256...47.
D9: 5 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
* PAIR G1: 1,9 BLK 3
G3: 1,9,5                                # reduction candidate for 1,9
G3: 5 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
G3: 1,9                                  #  9 pairs
* PAIR G2: 1,5 BLK 3
G3: 1,5,9                                # reduction candidate for 1,5
G3: 1,5 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
G3: 9 => CTR
* 942358167.3.9..542...2.493812.8..394....31286863429715789142653354697821216583479
* PAIR G2: 1,5 ROW 2
C2: 1,5,3,7,8                            # reduction candidate for 1,5
C2: 1,5                                  # 12 pairs
C2: 3,7,8                                #  9 pairs
* PAIR C4: 5,7 BLK 4
A5: 5,7,4,8,9                            # reduction candidate for 5,7
A5: 5,7 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
A5: 4,8,9 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
C5: 5,7,3,8,9                            # reduction candidate for 5,7
C5: 5,7 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
C5: 3,8,9                                #  9 pairs
* PAIR C4: 5,7 ROW 4
F4: 5,7,6                                # reduction candidate for 5,7
F4: 5,7 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
F4: 6 => CTR
* .42.5..67...9.7.427..2645381258763944.75..2.6.6.42.7.5...7426533746.582.256...47.
* PAIR C4: 5,7 COL C
C2: 5,7,1,3,8                            # reduction candidate for 5,7
C2: 5,7                                  # 20 pairs
C3: 5,7,1,9                              # reduction candidate for 5,7
C3: 5,7                                  # 10 pairs
* PAIR E4: 6,7 BLK 5
F4: 6,7,5                                # reduction candidate for 6,7
F4: 6,7 => CTR
* .42.5..67...9...42...2.4.381258..3944.75..2.6.6.42.7.5...7426533746.582.256...47.
F4: 5 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
* PAIR E4: 6,7 COL E
E2: 6,7,1,8                              # reduction candidate for 6,7
E2: 6,7 => CTR
* .42358167.319..5426.52149381278653945..4372.6.63.2.7.5....4265.3.469.8212.6.8.47.
E2: 1,8                                  # 15 pairs
E3: 6,7,1                                # reduction candidate for 6,7
E3: 6,7                                  # 15 pairs
* PAIR I8: 1,9 BLK 9
I7: 1,9,3                                # reduction candidate for 1,9
I7: 1,9 => CTR
* 842153967.319.6542...2.4.381278653944.573.2.69634217857.834265.3546..82.2.65..473
I7: 3                                    # 12 pairs
I9: 1,9,3                                # reduction candidate for 1,9
I9: 1,9                                  # 12 pairs
* PAIR I8: 1,9 ROW 8
B8: 1,9,5,7                              # reduction candidate for 1,9
B8: 1,9 => CTR
* .42.5..67...9...42...2.4.381258..394...5..2.6.6.42.7.5...7426533.46.582.256...47.
B8: 5,7                                  # 10 pairs
E8: 1,9,7                                # reduction candidate for 1,9
E8: 1,9                                  # 12 pairs
F8: 1,9,5,7                              # reduction candidate for 1,9
F8: 1,9 => CTR
* .42.5..67...9.7.42...2.4.3812786.394......2.6.6..2.7.5....4265.35467.82.2.6...47.
F8: 5,7                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-405-base-pr-000.dot
* REASONING
* DIS # A5: 8,9 => CTR => A5: 4,5,7
* PRF # A6: 8,9 => SOL
* DIS # A6: 4 => CTR => A6: 8,9
* DIS # A7: 8,9 => CTR => A7: 7
* PRF # A7: 7 => SOL
* PRF # F1: 1,3 => SOL
* DIS # F1: 8 => CTR => F1: 1,3
* DIS # D5: 1,3 => CTR => D5: 4,5,7
* DIS # D6: 1,3 => CTR => D6: 4
* PRF # D6: 4 => SOL
* PRF # D7: 1,3 => SOL
* DIS # D7: 7 => CTR => D7: 1,3
* DIS # D9: 1,3 => CTR => D9: 5
* PRF # D9: 5 => SOL
* PRF # G3: 5 => SOL
* PRF # G3: 1,5 => SOL
* DIS # G3: 9 => CTR => G3: 1,5
* DIS # A5: 5,7 => CTR => A5: 4,8,9
* PRF # A5: 4,8,9 => SOL
* PRF # C5: 5,7 => SOL
* PRF # F4: 5,7 => SOL
* DIS # F4: 6 => CTR => F4: 5,7
* DIS # F4: 6,7 => CTR => F4: 5
* PRF # F4: 5 => SOL
* DIS # E2: 6,7 => CTR => E2: 1,8
* DIS # I7: 1,9 => CTR => I7: 3
* DIS # B8: 1,9 => CTR => B8: 5,7
* DIS # F8: 1,9 => CTR => F8: 5,7
* CNT  28 HDP CHAINS /  43 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,C4,D1,E4,G1,G2,H5,H6,I8)
* .42.5..67...9...42...2.4.3812.8..394......2.6.6..2.7.5....4265.3.46..82.2.6...47.
* PAIR A1: 8,9 COL A
A5: 8,9,4,5,7                            # reduction candidate for 8,9
A5: 8,9 => CTR
* .42.5..67...9...42...2.4.3812.8..394...4..2.646..2.7.5...7426533746.582.256...47.
A6: 8,9,4                                # reduction candidate for 8,9
A6: 8,9 => SOLVED
* 842351967573986142691274538127865394435719286968423715789142653354697821216538479
* DURATION: 0:00:03.650949  START: 16:42:34.227099  END: 16:42:37.878048 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-405-base-pr-001.dot
* REASONING
* DIS # A5: 8,9 => CTR => A5: 4,5,7
* PRF A5: 4,5,7 # A6: 8,9 => SOL
* STA A5: 4,5,7 + A6: 8,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 405

solution: 842351967573986142691274538127865394435719286968423715789142653354697821216538479
info: 94802    FNBXK    S8.f     18902

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

Solution

position: 842351967573986142691274538127865394435719286968423715789142653354697821216538479 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 # A5: 8,9 => CTR => A5: 4,5,7
* INC # A5: 4,5,7 => UNS
* PRF # A6: 8,9 => SOL
* DIS # A6: 4 => CTR => A6: 8,9
* DIS # A7: 8,9 => CTR => A7: 7
* PRF # A7: 7 => SOL
* PRF # F1: 1,3 => SOL
* DIS # F1: 8 => CTR => F1: 1,3
* DIS # D5: 1,3 => CTR => D5: 4,5,7
* INC # D5: 4,5,7 => UNS
* DIS # D6: 1,3 => CTR => D6: 4
* PRF # D6: 4 => SOL
* PRF # D7: 1,3 => SOL
* DIS # D7: 7 => CTR => D7: 1,3
* DIS # D9: 1,3 => CTR => D9: 5
* PRF # D9: 5 => SOL
* INC # G3: 1,9 => UNS
* PRF # G3: 5 => SOL
* PRF # G3: 1,5 => SOL
* DIS # G3: 9 => CTR => G3: 1,5
* INC # C2: 1,5 => UNS
* INC # C2: 3,7,8 => UNS
* DIS # A5: 5,7 => CTR => A5: 4,8,9
* PRF # A5: 4,8,9 => SOL
* PRF # C5: 5,7 => SOL
* INC # C5: 3,8,9 => UNS
* PRF # F4: 5,7 => SOL
* DIS # F4: 6 => CTR => F4: 5,7
* INC # C2: 5,7 => UNS
* INC # C3: 5,7 => UNS
* DIS # F4: 6,7 => CTR => F4: 5
* PRF # F4: 5 => SOL
* DIS # E2: 6,7 => CTR => E2: 1,8
* INC # E2: 1,8 => UNS
* INC # E3: 6,7 => UNS
* DIS # I7: 1,9 => CTR => I7: 3
* INC # I7: 3 => UNS
* INC # I9: 1,9 => UNS
* DIS # B8: 1,9 => CTR => B8: 5,7
* INC # B8: 5,7 => UNS
* INC # E8: 1,9 => UNS
* DIS # F8: 1,9 => CTR => F8: 5,7
* INC # F8: 5,7 => UNS
* CNT  43 HDP CHAINS /  43 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A5: 8,9 => CTR => A5: 4,5,7
* PRF A5: 4,5,7 # A6: 8,9 => SOL
* STA A5: 4,5,7 + A6: 8,9
* CNT   2 HDP CHAINS /   2 HYP OPENED