Analysis of xx-top500-262-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 63.7........9..2........1..3....5.8..4..2........1....5.2...4.....4...3.......... initial

Autosolve

position: 631782.4..549.12..2..5.41..32.645.8114..2..5...5.1..24582173496.1.4...324.32...1. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C3: 9 => CTR => C3: 7,8
* DIS # A6: 9 => CTR => A6: 7,8
* PRF # C3: 8 => SOL
* PRF # B6: 7,9 => SOL
* PRF # B6: 7,9 => SOL
* PRF # C8: 7,9 => SOL
* PRF # B6: 7,9 => SOL
* PRF # C8: 7,9 => SOL
* PRF # A6: 8 => SOL
* PRF # G9: 5,7 => SOL
* CNT  10 HDP CHAINS /  26 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 # C3: 9 => CTR => C3: 7,8
* PRF C3: 7,8 # A6: 7,8 => SOL
* STA C3: 7,8 + A6: 7,8
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

63.7........9..2........1..3....5.8..4..2........1....5.2...4.....4...3.......... initial
631782.4..549.12..2..5.41..32.645.8114..2..5...5.1..24582173496.1.4...324.32...1. autosolve
631782945754931268298564173329645781146827359875319624582173496917456832463298517 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (26)
A2: 7,8
B3: 7,9
E2: 3,6
E3: 3,6
G1: 5,9
I1: 5,9
H2: 6,7
I2: 3,8
H3: 6,7
I3: 3,8
C4: 7,9
C5: 6,8
D5: 3,8
F5: 7,9
D6: 3,8
F6: 7,9
G4: 7,9
G5: 3,6
I5: 7,9
G6: 3,6
A8: 7,9
E8: 5,9
F8: 6,8
E9: 5,9
F9: 6,8
I9: 5,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,E3: 3.. / E2 = 3  =>  0 pairs (*) / E3 = 3  =>  0 pairs (X)
I2,I3: 3.. / I2 = 3  => 16 pairs (_) / I3 = 3  =>  0 pairs (*)
D5,D6: 3.. / D5 = 3  => 16 pairs (_) / D6 = 3  =>  0 pairs (*)
G5,G6: 3.. / G5 = 3  =>  0 pairs (*) / G6 = 3  =>  0 pairs (X)
E2,I2: 3.. / E2 = 3  =>  0 pairs (*) / I2 = 3  =>  0 pairs (X)
E3,I3: 3.. / E3 = 3  => 16 pairs (_) / I3 = 3  =>  0 pairs (*)
D5,G5: 3.. / D5 = 3  => 16 pairs (_) / G5 = 3  =>  0 pairs (*)
D6,G6: 3.. / D6 = 3  =>  0 pairs (*) / G6 = 3  =>  0 pairs (X)
G1,I1: 5.. / G1 = 5  => 23 pairs (_) / I1 = 5  =>  0 pairs (*)
E8,E9: 5.. / E8 = 5  => 26 pairs (_) / E9 = 5  =>  0 pairs (X)
E8,G8: 5.. / E8 = 5  => 26 pairs (_) / G8 = 5  =>  0 pairs (X)
I1,I9: 5.. / I1 = 5  =>  0 pairs (*) / I9 = 5  =>  0 pairs (X)
E2,E3: 6.. / E2 = 6  => 16 pairs (_) / E3 = 6  =>  0 pairs (*)
H2,H3: 6.. / H2 = 6  =>  0 pairs (*) / H3 = 6  =>  0 pairs (X)
C5,B6: 6.. / C5 = 6  =>  0 pairs (*) / B6 = 6  =>  0 pairs (X)
G5,G6: 6.. / G5 = 6  => 16 pairs (_) / G6 = 6  =>  0 pairs (*)
C8,B9: 6.. / C8 = 6  => 16 pairs (_) / B9 = 6  =>  0 pairs (*)
F8,F9: 6.. / F8 = 6  =>  0 pairs (*) / F9 = 6  =>  0 pairs (X)
E2,H2: 6.. / E2 = 6  => 16 pairs (_) / H2 = 6  =>  0 pairs (*)
E3,H3: 6.. / E3 = 6  =>  0 pairs (*) / H3 = 6  =>  0 pairs (X)
C5,G5: 6.. / C5 = 6  =>  0 pairs (*) / G5 = 6  =>  0 pairs (X)
B6,G6: 6.. / B6 = 6  => 16 pairs (_) / G6 = 6  =>  0 pairs (*)
C8,F8: 6.. / C8 = 6  => 16 pairs (_) / F8 = 6  =>  0 pairs (*)
B9,F9: 6.. / B9 = 6  =>  0 pairs (*) / F9 = 6  =>  0 pairs (X)
B6,B9: 6.. / B6 = 6  => 16 pairs (_) / B9 = 6  =>  0 pairs (*)
C5,C8: 6.. / C5 = 6  =>  0 pairs (*) / C8 = 6  =>  0 pairs (X)
H2,H3: 7.. / H2 = 7  => 16 pairs (_) / H3 = 7  =>  0 pairs (*)
F5,F6: 7.. / F5 = 7  =>  0 pairs (*) / F6 = 7  =>  0 pairs (X)
G4,I5: 7.. / G4 = 7  =>  0 pairs (*) / I5 = 7  =>  0 pairs (X)
A2,H2: 7.. / A2 = 7  =>  0 pairs (*) / H2 = 7  =>  0 pairs (X)
C4,G4: 7.. / C4 = 7  => 23 pairs (_) / G4 = 7  =>  0 pairs (*)
F5,I5: 7.. / F5 = 7  =>  0 pairs (*) / I5 = 7  =>  0 pairs (X)
I5,I9: 7.. / I5 = 7  => 23 pairs (_) / I9 = 7  =>  0 pairs (*)
A2,C3: 8.. / A2 = 8  => 16 pairs (_) / C3 = 8  =>  0 pairs (*)
I2,I3: 8.. / I2 = 8  =>  0 pairs (*) / I3 = 8  =>  0 pairs (X)
C5,A6: 8.. / C5 = 8  => 16 pairs (_) / A6 = 8  =>  0 pairs (*)
D5,D6: 8.. / D5 = 8  =>  0 pairs (*) / D6 = 8  =>  0 pairs (X)
F8,F9: 8.. / F8 = 8  => 16 pairs (_) / F9 = 8  =>  0 pairs (*)
G8,G9: 8.. / G8 = 8  =>  0 pairs (*) / G9 = 8  =>  0 pairs (X)
A2,I2: 8.. / A2 = 8  => 16 pairs (_) / I2 = 8  =>  0 pairs (*)
C3,I3: 8.. / C3 = 8  =>  0 pairs (*) / I3 = 8  =>  0 pairs (X)
C5,D5: 8.. / C5 = 8  => 16 pairs (_) / D5 = 8  =>  0 pairs (*)
A6,D6: 8.. / A6 = 8  =>  0 pairs (*) / D6 = 8  =>  0 pairs (X)
F8,G8: 8.. / F8 = 8  => 16 pairs (_) / G8 = 8  =>  0 pairs (*)
F9,G9: 8.. / F9 = 8  =>  0 pairs (*) / G9 = 8  =>  0 pairs (X)
A2,A6: 8.. / A2 = 8  => 16 pairs (_) / A6 = 8  =>  0 pairs (*)
C3,C5: 8.. / C3 = 8  =>  0 pairs (*) / C5 = 8  =>  0 pairs (X)
B3,C3: 9.. / B3 = 9  => 27 pairs (_) / C3 = 9  =>  0 pairs (X)
G1,I1: 9.. / G1 = 9  =>  0 pairs (*) / I1 = 9  =>  0 pairs (X)
F5,F6: 9.. / F5 = 9  => 23 pairs (_) / F6 = 9  =>  0 pairs (*)
G4,I5: 9.. / G4 = 9  => 23 pairs (_) / I5 = 9  =>  0 pairs (*)
E8,E9: 9.. / E8 = 9  =>  0 pairs (X) / E9 = 9  => 26 pairs (_)
C4,G4: 9.. / C4 = 9  =>  0 pairs (*) / G4 = 9  =>  0 pairs (X)
F5,I5: 9.. / F5 = 9  => 23 pairs (_) / I5 = 9  =>  0 pairs (*)
B9,E9: 9.. / B9 = 9  =>  0 pairs (X) / E9 = 9  => 26 pairs (_)
A6,A8: 9.. / A6 = 9  =>  0 pairs (X) / A8 = 9  => 27 pairs (_)
G1,G4: 9.. / G1 = 9  =>  0 pairs (*) / G4 = 9  =>  0 pairs (X)
I1,I5: 9.. / I1 = 9  => 23 pairs (_) / I5 = 9  =>  0 pairs (*)
* DURATION: 0:02:03.910817  START: 11:47:24.624162  END: 11:49:28.534979 2017-05-04
* CP COUNT: (58)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B3,C4,C5,D5,D6,E2,E3,E8,E9,F5,F6,F8,F9,G1,G4,G5,G6,H2,H3,I1,I2,I3,I5,I9)
* 631782.4..549.12..2..5.41..32.645.8114..2..5...5.1..24582173496.1.4...324.32...1.
* PAIR A2: 7,8 BLK 1
C3: 7,8,9                                # reduction candidate for 7,8
C3: 9 => CTR
* 631782.4.8549.12732795341683276459811483296579658173245821734967164985324.32...1.
C3: 7,8                                  # 27 pairs
* PAIR A2: 7,8 COL A
A6: 7,8,9                                # reduction candidate for 7,8
A6: 9 => CTR
* 631782.4.8549.12732..53416832.645.8114832.65.965817324582173496716498532493256817
A6: 7,8                                  # 27 pairs
* PAIR B3: 7,9 BLK 1
C3: 7,9,8                                # reduction candidate for 7,9
C3: 8 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
C3: 7,9                                  # 16 pairs
* PAIR B3: 7,9 COL B
B6: 7,9,6                                # reduction candidate for 7,9
B6: 7,9 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
B6: 6                                    # 16 pairs
B9: 7,9,6                                # reduction candidate for 7,9
B9: 7,9                                  # 16 pairs
* PAIR C4: 7,9 BLK 4
A6: 7,9,8                                # reduction candidate for 7,9
A6: 7,9                                  # 16 pairs
B6: 7,9,6                                # reduction candidate for 7,9
B6: 7,9 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
B6: 6                                    # 16 pairs
* PAIR C4: 7,9 COL C
C3: 7,9,8                                # reduction candidate for 7,9
C3: 7,9                                  # 16 pairs
C8: 7,9,6                                # reduction candidate for 7,9
C8: 7,9 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
C8: 6                                    # 16 pairs
* PAIR F6: 7,9 ROW 6
A6: 7,9,8                                # reduction candidate for 7,9
A6: 7,9                                  # 16 pairs
B6: 7,9,6                                # reduction candidate for 7,9
B6: 7,9 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
B6: 6                                    # 16 pairs
* PAIR A8: 7,9 BLK 7
C8: 7,9,6                                # reduction candidate for 7,9
C8: 7,9 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
C8: 6                                    # 16 pairs
B9: 7,9,6                                # reduction candidate for 7,9
B9: 7,9                                  # 16 pairs
* PAIR A8: 7,9 COL A
A6: 7,9,8                                # reduction candidate for 7,9
A6: 8 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
A6: 7,9                                  # 16 pairs
* PAIR I9: 5,7 BLK 9
G8: 5,7,8                                # reduction candidate for 5,7
G8: 5,7                                  # 16 pairs
G9: 5,7,8                                # reduction candidate for 5,7
G9: 5,7 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
G9: 8                                    # 16 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-262-base-pr-000.dot
* REASONING
* DIS # C3: 9 => CTR => C3: 7,8
* DIS # A6: 9 => CTR => A6: 7,8
* PRF # C3: 8 => SOL
* PRF # B6: 7,9 => SOL
* PRF # B6: 7,9 => SOL
* PRF # C8: 7,9 => SOL
* PRF # B6: 7,9 => SOL
* PRF # C8: 7,9 => SOL
* PRF # A6: 8 => SOL
* PRF # G9: 5,7 => SOL
* CNT  10 HDP CHAINS /  26 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B3,C4,C5,D5,D6,E2,E3,E8,E9,F5,F6,F8,F9,G1,G4,G5,G6,H2,H3,I1,I2,I3,I5,I9)
* 631782.4..549.12..2..5.41..32.645.8114..2..5...5.1..24582173496.1.4...324.32...1.
* PAIR A2: 7,8 BLK 1
C3: 7,8,9                                # reduction candidate for 7,8
C3: 9 => CTR
* 631782.4.8549.12732795341683276459811483296579658173245821734967164985324.32...1.
* PAIR A2: 7,8 COL A
A6: 7,8,9                                # reduction candidate for 7,8
A6: 7,8 => SOLVED
* 631782945754931268298564173329645781146827359875319624582173496917456832463298517
* DURATION: 0:00:04.874744  START: 11:50:06.076040  END: 11:50:10.950784 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-262-base-pr-001.dot
* REASONING
* DIS # C3: 9 => CTR => C3: 7,8
* PRF C3: 7,8 # A6: 7,8 => SOL
* STA C3: 7,8 + A6: 7,8
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 262

solution: 631782945754931268298564173329645781146827359875319624582173496917456832463298517
info: 2092     FNBTWY   S8.f     35866

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

Solution

position: 631782945754931268298564173329645781146827359875319624582173496917456832463298517 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 # C3: 7,8 => UNS
* DIS # C3: 9 => CTR => C3: 7,8
* INC # A6: 7,8 => UNS
* DIS # A6: 9 => CTR => A6: 7,8
* INC # C3: 7,9 => UNS
* PRF # C3: 8 => SOL
* PRF # B6: 7,9 => SOL
* INC # B6: 6 => UNS
* INC # B9: 7,9 => UNS
* INC # A6: 7,9 => UNS
* PRF # B6: 7,9 => SOL
* INC # B6: 6 => UNS
* INC # C3: 7,9 => UNS
* PRF # C8: 7,9 => SOL
* INC # C8: 6 => UNS
* INC # A6: 7,9 => UNS
* PRF # B6: 7,9 => SOL
* INC # B6: 6 => UNS
* PRF # C8: 7,9 => SOL
* INC # C8: 6 => UNS
* INC # B9: 7,9 => UNS
* INC # A6: 7,9 => UNS
* PRF # A6: 8 => SOL
* INC # G8: 5,7 => UNS
* PRF # G9: 5,7 => SOL
* INC # G9: 8 => UNS
* CNT  26 HDP CHAINS /  26 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C3: 7,8 => UNS
* DIS # C3: 9 => CTR => C3: 7,8
* PRF C3: 7,8 # A6: 7,8 => SOL
* STA C3: 7,8 + A6: 7,8
* CNT   3 HDP CHAINS /   3 HYP OPENED