Analysis of xx-top500-355-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...35....8.......4...2.........1...7.2...5.........3..76.8.....1......5.......24. initial

Autosolve

position: 2.435..7.8531.7.24...24..3543..125.7.2.7354..5..48.3.2765824..3142..3758389571246 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B3: 1,9 => SOL
* PRF # B6: 7 => SOL
* DIS # G3: 8,9 => CTR => G3: 1
* PRF # G3: 1 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* PRF # C5: 6,8 => SOL
* DIS # C5: 1 => CTR => C5: 6,8
* DIS # H4: 6,8 => CTR => H4: 9
* PRF # H4: 9 => SOL
* DIS # H5: 6,9 => CTR => H5: 1,8
* DIS # H4: 8 => CTR => H4: 6,9
* PRF # H6: 6,9 => SOL
* DIS # H6: 1 => CTR => H6: 6,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* CNT  22 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:

* PRF # B3: 1,9 => SOL
* STA B3: 1,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

...35....8.......4...2.........1...7.2...5.........3..76.8.....1......5.......24. initial
2.435..7.8531.7.24...24..3543..125.7.2.7354..5..48.3.2765824..3142..3758389571246 autosolve
214356879853197624697248135438612597926735481571489362765824913142963758389571246 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
B1: 1,9
A3: 6,9
F1: 6,8
E2: 6,9
F3: 8,9
G1: 6,8
I1: 1,9
G2: 6,9
C4: 6,8
A5: 6,9
D4: 6,9
F6: 6,9
I5: 1,9
D8: 6,9
E8: 6,9
G7: 1,9
H7: 1,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I1,G3: 1.. / I1 = 1  =>  0 pairs (X) / G3 = 1  =>  0 pairs (_)
G7,H7: 1.. / G7 = 1  =>  0 pairs (X) / H7 = 1  =>  0 pairs (_)
B1,I1: 1.. / B1 = 1  =>  0 pairs (*) / I1 = 1  =>  0 pairs (X)
G3,G7: 1.. / G3 = 1  =>  0 pairs (*) / G7 = 1  =>  0 pairs (X)
I1,I5: 1.. / I1 = 1  =>  0 pairs (X) / I5 = 1  =>  0 pairs (_)
A3,C3: 6.. / A3 = 6  =>  0 pairs (*) / C3 = 6  =>  0 pairs (X)
F1,E2: 6.. / F1 = 6  =>  0 pairs (*) / E2 = 6  =>  0 pairs (X)
G1,G2: 6.. / G1 = 6  =>  0 pairs (X) / G2 = 6  =>  0 pairs (_)
D4,F6: 6.. / D4 = 6  =>  0 pairs (*) / F6 = 6  =>  0 pairs (X)
D8,E8: 6.. / D8 = 6  =>  0 pairs (X) / E8 = 6  =>  0 pairs (_)
F1,G1: 6.. / F1 = 6  =>  0 pairs (*) / G1 = 6  =>  0 pairs (X)
E2,G2: 6.. / E2 = 6  =>  0 pairs (X) / G2 = 6  =>  0 pairs (_)
A3,A5: 6.. / A3 = 6  =>  0 pairs (*) / A5 = 6  =>  0 pairs (X)
D4,D8: 6.. / D4 = 6  =>  0 pairs (*) / D8 = 6  =>  0 pairs (X)
E2,E8: 6.. / E2 = 6  =>  0 pairs (X) / E8 = 6  =>  0 pairs (_)
F1,F6: 6.. / F1 = 6  =>  0 pairs (*) / F6 = 6  =>  0 pairs (X)
B3,C3: 7.. / B3 = 7  => 19 pairs (_) / C3 = 7  =>  0 pairs (*)
B6,C6: 7.. / B6 = 7  =>  0 pairs (*) / C6 = 7  =>  0 pairs (X)
B3,B6: 7.. / B3 = 7  => 19 pairs (_) / B6 = 7  =>  0 pairs (*)
C3,C6: 7.. / C3 = 7  =>  0 pairs (*) / C6 = 7  =>  0 pairs (X)
F1,F3: 8.. / F1 = 8  =>  0 pairs (X) / F3 = 8  =>  0 pairs (_)
G1,G3: 8.. / G1 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
C4,C5: 8.. / C4 = 8  => 19 pairs (_) / C5 = 8  =>  0 pairs (X)
H4,H5: 8.. / H4 = 8  =>  0 pairs (X) / H5 = 8  => 19 pairs (_)
F1,G1: 8.. / F1 = 8  =>  0 pairs (X) / G1 = 8  =>  0 pairs (_)
F3,G3: 8.. / F3 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
C4,H4: 8.. / C4 = 8  => 19 pairs (_) / H4 = 8  =>  0 pairs (X)
C5,H5: 8.. / C5 = 8  =>  0 pairs (X) / H5 = 8  => 19 pairs (_)
E2,F3: 9.. / E2 = 9  =>  0 pairs (*) / F3 = 9  =>  0 pairs (X)
A5,B6: 9.. / A5 = 9  =>  0 pairs (*) / B6 = 9  =>  0 pairs (X)
D4,F6: 9.. / D4 = 9  =>  0 pairs (X) / F6 = 9  =>  0 pairs (_)
D8,E8: 9.. / D8 = 9  =>  0 pairs (*) / E8 = 9  =>  0 pairs (X)
G7,H7: 9.. / G7 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
B1,I1: 9.. / B1 = 9  =>  0 pairs (X) / I1 = 9  =>  0 pairs (_)
E2,G2: 9.. / E2 = 9  =>  0 pairs (*) / G2 = 9  =>  0 pairs (X)
D4,H4: 9.. / D4 = 9  =>  0 pairs (X) / H4 = 9  =>  0 pairs (_)
A3,A5: 9.. / A3 = 9  =>  0 pairs (X) / A5 = 9  =>  0 pairs (_)
D4,D8: 9.. / D4 = 9  =>  0 pairs (X) / D8 = 9  =>  0 pairs (_)
E2,E8: 9.. / E2 = 9  =>  0 pairs (*) / E8 = 9  =>  0 pairs (X)
F3,F6: 9.. / F3 = 9  =>  0 pairs (X) / F6 = 9  =>  0 pairs (_)
I1,I5: 9.. / I1 = 9  =>  0 pairs (*) / I5 = 9  =>  0 pairs (X)
* DURATION: 0:01:10.360808  START: 14:53:10.940397  END: 14:54:21.301205 2017-05-04
* CP COUNT: (41)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A5,B1,C4,D4,D8,E2,E8,F1,F3,F6,G1,G2,G7,H7,I1,I5)
* 2.435..7.8531.7.24...24..3543..125.7.2.7354..5..48.3.2765824..3142..3758389571246
* PAIR B1: 1,9 BLK 1
B3: 1,9,7                                # reduction candidate for 1,9
B3: 1,9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
B3: 7                                    # 19 pairs
* PAIR B1: 1,9 COL B
B6: 1,9,7                                # reduction candidate for 1,9
B6: 7 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
B6: 1,9                                  # 19 pairs
* PAIR F3: 8,9 ROW 3
G3: 8,9,1                                # reduction candidate for 8,9
G3: 8,9 => CTR
* 2.435..718531.7.24...24..3543..125.7.2.7354.959.48.3.2765824..3142..3758389571246
G3: 1 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
* PAIR I1: 1,9 BLK 3
G3: 1,9,8                                # reduction candidate for 1,9
G3: 1,9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
G3: 8 => CTR
* 2.435..718531.7924...24983543.9125.792.7354..5..48.3.2765824..3142..3758389571246
* PAIR C4: 6,8 BLK 4
C5: 6,8,1                                # reduction candidate for 6,8
C5: 6,8 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
C5: 1 => CTR
* 2.435..7.8531.7.24...24..35438.125.7.21735489597486312765824193142693758389571246
* PAIR C4: 6,8 ROW 4
H4: 6,8,9                                # reduction candidate for 6,8
H4: 6,8 => CTR
* 2.435867.853167924...24983543.9125.792.7354.15..4863.2765824..3142693758389571246
H4: 9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
* PAIR A5: 6,9 ROW 5
H5: 6,9,1,8                              # reduction candidate for 6,9
H5: 6,9 => CTR
* 21435..79853197624...248135436912587.287354.15..48.3.2765824.13142..3758389571246
H5: 1,8                                  # 19 pairs
* PAIR D4: 6,9 ROW 4
H4: 6,9,8                                # reduction candidate for 6,9
H4: 8 => CTR
* 2.435867.853167924...2498354369125879287354615..4863.2765824..3142693758389571246
H4: 6,9                                  # 19 pairs
* PAIR F6: 6,9 ROW 6
H6: 6,9,1                                # reduction candidate for 6,9
H6: 6,9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
H6: 1 => CTR
* 2.435..718531.7.24.1724..3543.9125.7.217354..5..48.312765824193142..3758389571246
* PAIR I5: 1,9 BLK 6
H5: 1,9,6,8                              # reduction candidate for 1,9
H5: 1,9 => CTR
* 2.435..7.8531.7.24...24..3543..12587.287354..5..48.362765824..3142..3758389571246
H5: 6,8                                  # 18 pairs
H6: 1,9,6                                # reduction candidate for 1,9
H6: 1,9 => CTR
* 2.435867.853167924...24983543.9125.792.7354.15..4863.2765824..3142693758389571246
H6: 6 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
* PAIR G7: 1,9 COL G
G3: 1,9,8                                # reduction candidate for 1,9
G3: 1,9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
G3: 8 => CTR
* 2.435..718531.7924...24983543.9125.792.7354..5..48.3.2765824..3142..3758389571246
* PAIR H7: 1,9 COL H
H5: 1,9,6,8                              # reduction candidate for 1,9
H5: 1,9 => CTR
* 2.435..7.8531.7.24...24..3543..12587.287354..5..48.362765824..3142..3758389571246
H5: 6,8                                  # 18 pairs
H6: 1,9,6                                # reduction candidate for 1,9
H6: 1,9 => CTR
* 2.435867.853167924...24983543.9125.792.7354.15..4863.2765824..3142693758389571246
H6: 6 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-355-base-pr-000.dot
* REASONING
* PRF # B3: 1,9 => SOL
* PRF # B6: 7 => SOL
* DIS # G3: 8,9 => CTR => G3: 1
* PRF # G3: 1 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* PRF # C5: 6,8 => SOL
* DIS # C5: 1 => CTR => C5: 6,8
* DIS # H4: 6,8 => CTR => H4: 9
* PRF # H4: 9 => SOL
* DIS # H5: 6,9 => CTR => H5: 1,8
* DIS # H4: 8 => CTR => H4: 6,9
* PRF # H6: 6,9 => SOL
* DIS # H6: 1 => CTR => H6: 6,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* CNT  22 HDP CHAINS /  28 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A5,B1,C4,D4,D8,E2,E8,F1,F3,F6,G1,G2,G7,H7,I1,I5)
* 2.435..7.8531.7.24...24..3543..125.7.2.7354..5..48.3.2765824..3142..3758389571246
* PAIR B1: 1,9 BLK 1
B3: 1,9,7                                # reduction candidate for 1,9
B3: 1,9 => SOLVED
* 214356879853197624697248135438612597926735481571489362765824913142963758389571246
* DURATION: 0:00:02.101689  START: 14:54:53.294798  END: 14:54:55.396487 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-355-base-pr-001.dot
* REASONING
* PRF # B3: 1,9 => SOL
* STA B3: 1,9
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 355

solution: 214356879853197624697248135438612597926735481571489362765824913142963758389571246
info: 4886     FNBTWX   S8.f     41560

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

Solution

position: 214356879853197624697248135438612597926735481571489362765824913142963758389571246 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 # B3: 1,9 => SOL
* INC # B3: 7 => UNS
* INC # B6: 1,9 => UNS
* PRF # B6: 7 => SOL
* DIS # G3: 8,9 => CTR => G3: 1
* PRF # G3: 1 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* PRF # C5: 6,8 => SOL
* DIS # C5: 1 => CTR => C5: 6,8
* DIS # H4: 6,8 => CTR => H4: 9
* PRF # H4: 9 => SOL
* DIS # H5: 6,9 => CTR => H5: 1,8
* INC # H5: 1,8 => UNS
* INC # H4: 6,9 => UNS
* DIS # H4: 8 => CTR => H4: 6,9
* PRF # H6: 6,9 => SOL
* DIS # H6: 1 => CTR => H6: 6,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* INC # H5: 6,8 => UNS
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* PRF # G3: 1,9 => SOL
* DIS # G3: 8 => CTR => G3: 1,9
* DIS # H5: 1,9 => CTR => H5: 6,8
* INC # H5: 6,8 => UNS
* DIS # H6: 1,9 => CTR => H6: 6
* PRF # H6: 6 => SOL
* CNT  28 HDP CHAINS /  28 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # B3: 1,9 => SOL
* STA B3: 1,9
* CNT   1 HDP CHAINS /   1 HYP OPENED