Analysis of xx-top500-469-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 3...6..........1.4......9...41..9..8....3..2...........5.8.1...2......6....4..... initial

Autosolve

position: 3...6.....6..8.1.4......9.66412.93.8....3..2...........568.1..32......6....4.6... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A3: 5,7,8 => CTR => A3: 1,4
* DIS # D5: 5,7 => CTR => D5: 1,6
* DIS # F5: 5,7 => CTR => F5: 4,8
* PRF # D6: 5,7 => SOL
* DIS # F6: 5,7 => CTR => F6: 4,8
* DIS # E8: 5,7 => CTR => E8: 9
* DIS # H6: 9 => CTR => H6: 1,4
* PRF # G5: 5,7 => SOL
* DIS # I5: 5,7 => CTR => I5: 1,9
* DIS # G6: 5,7 => CTR => G6: 4,6
* DIS # I6: 5,7 => CTR => I6: 1,9
* DIS # H1: 5,7 => CTR => H1: 8
* DIS # A7: 7 => CTR => A7: 4,9
* DIS # H6: 1 => CTR => H6: 4,9
* DIS # I8: 1,9 => CTR => I8: 5,7
* DIS # I9: 1,9 => CTR => I9: 2,5,7
* DIS # B9: 1,9 => CTR => B9: 3,7,8
* DIS # H6: 1,9 => CTR => H6: 4
* CNT  18 HDP CHAINS /  40 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 # A3: 5,7,8 => CTR => A3: 1,4
* DIS A3: 1,4 # D5: 5,7 => CTR => D5: 1,6
* DIS A3: 1,4 + D5: 1,6 # F5: 5,7 => CTR => F5: 4,8
* PRF A3: 1,4 + D5: 1,6 + F5: 4,8 # D6: 5,7 => SOL
* STA A3: 1,4 + D5: 1,6 + F5: 4,8 + D6: 5,7
* CNT   4 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

3...6..........1.4......9...41..9..8....3..2...........5.8.1...2......6....4..... initial
3...6.....6..8.1.4......9.66412.93.8....3..2...........568.1..32......6....4.6... autosolve
394165782765982134182347956641259378879634521523718649456871293218593467937426815 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
E3: 1,4
B6: 2,3
C6: 2,3
E4: 5,7
E6: 1,4
H4: 5,7
H7: 4,9
H9: 1,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B1,D1: 1.. / B1 = 1  =>  0 pairs (X) / D1 = 1  => 16 pairs (_)
D5,I5: 1.. / D5 = 1  =>  0 pairs (X) / I5 = 1  => 16 pairs (_)
B8,I8: 1.. / B8 = 1  => 16 pairs (_) / I8 = 1  =>  0 pairs (X)
A3,A9: 1.. / A3 = 1  => 16 pairs (_) / A9 = 1  =>  0 pairs (X)
E3,E6: 1.. / E3 = 1  =>  0 pairs (X) / E6 = 1  => 16 pairs (_)
H6,H9: 1.. / H6 = 1  =>  0 pairs (X) / H9 = 1  => 16 pairs (_)
F2,F3: 2.. / F2 = 2  =>  8 pairs (_) / F3 = 2  =>  6 pairs (_)
G1,I1: 2.. / G1 = 2  => 10 pairs (_) / I1 = 2  =>  9 pairs (_)
B6,C6: 2.. / B6 = 2  =>  6 pairs (_) / C6 = 2  =>  6 pairs (_)
E7,E9: 2.. / E7 = 2  =>  9 pairs (_) / E9 = 2  => 10 pairs (_)
C2,F2: 2.. / C2 = 2  =>  6 pairs (_) / F2 = 2  =>  8 pairs (_)
E7,G7: 2.. / E7 = 2  =>  9 pairs (_) / G7 = 2  => 10 pairs (_)
B3,B6: 2.. / B3 = 2  =>  6 pairs (_) / B6 = 2  =>  6 pairs (_)
I1,I9: 2.. / I1 = 2  =>  9 pairs (_) / I9 = 2  => 10 pairs (_)
H2,H3: 3.. / H2 = 3  =>  8 pairs (_) / H3 = 3  =>  9 pairs (_)
B6,C6: 3.. / B6 = 3  =>  6 pairs (_) / C6 = 3  =>  6 pairs (_)
B9,C9: 3.. / B9 = 3  =>  6 pairs (_) / C9 = 3  =>  6 pairs (_)
D8,F8: 3.. / D8 = 3  => 11 pairs (_) / F8 = 3  =>  9 pairs (_)
B6,B9: 3.. / B6 = 3  =>  6 pairs (_) / B9 = 3  =>  6 pairs (_)
C6,C9: 3.. / C6 = 3  =>  6 pairs (_) / C9 = 3  =>  6 pairs (_)
A7,C8: 4.. / A7 = 4  => 16 pairs (_) / C8 = 4  =>  0 pairs (X)
C1,F1: 4.. / C1 = 4  => 16 pairs (_) / F1 = 4  =>  0 pairs (X)
F5,G5: 4.. / F5 = 4  => 16 pairs (_) / G5 = 4  =>  0 pairs (X)
C8,G8: 4.. / C8 = 4  =>  0 pairs (X) / G8 = 4  => 16 pairs (_)
A3,A7: 4.. / A3 = 4  =>  0 pairs (X) / A7 = 4  => 16 pairs (_)
E3,E6: 4.. / E3 = 4  => 16 pairs (_) / E6 = 4  =>  0 pairs (X)
H6,H7: 4.. / H6 = 4  => 16 pairs (_) / H7 = 4  =>  0 pairs (X)
E4,H4: 5.. / E4 = 5  => 14 pairs (_) / H4 = 5  => 15 pairs (_)
D5,D6: 6.. / D5 = 6  =>  0 pairs (*) / D6 = 6  =>  0 pairs (X)
G5,G6: 6.. / G5 = 6  =>  0 pairs (X) / G6 = 6  =>  0 pairs (_)
D5,G5: 6.. / D5 = 6  =>  0 pairs (*) / G5 = 6  =>  0 pairs (X)
D6,G6: 6.. / D6 = 6  =>  0 pairs (X) / G6 = 6  =>  0 pairs (_)
E4,H4: 7.. / E4 = 7  => 15 pairs (_) / H4 = 7  => 14 pairs (_)
H1,H3: 8.. / H1 = 8  =>  8 pairs (_) / H3 = 8  =>  0 pairs (X)
F5,F6: 8.. / F5 = 8  =>  0 pairs (X) / F6 = 8  =>  8 pairs (_)
G8,G9: 8.. / G8 = 8  =>  0 pairs (X) / G9 = 8  => 16 pairs (_)
A6,F6: 8.. / A6 = 8  =>  0 pairs (X) / F6 = 8  =>  8 pairs (_)
D1,D2: 9.. / D1 = 9  =>  0 pairs (X) / D2 = 9  =>  9 pairs (_)
* DURATION: 0:01:14.776143  START: 18:43:13.630116  END: 18:44:28.406259 2017-05-04
* CP COUNT: (38)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B6,C6,E3,E4,E6,H4,H7,H9)
* 3...6.....6..8.1.4......9.66412.93.8....3..2...........568.1..32......6....4.6...
* PAIR E3: 1,4 ROW 3
A3: 1,4,5,7,8                            # reduction candidate for 1,4
A3: 5,7,8 => CTR
* 3...6.....6..8.1.4......9.66412.93.8....3..2..........4568.1.932.....46.1..4.6...
A3: 1,4                                  #  9 pairs
* PAIR E4: 5,7 BLK 5
D5: 5,7,1,6                              # reduction candidate for 5,7
D5: 5,7 => CTR
* 39416..8..6.98.1.418..4.9.66412.93.8879534621523618749456871.93218.9.46.9..4.681.
D5: 1,6                                  #  9 pairs
F5: 5,7,4,8                              # reduction candidate for 5,7
F5: 5,7 => CTR
* 3...64....6..8.1.44...1.9.66412.93.8...63.421...14869..568.1.43214...86....4.6.1.
F5: 4,8                                  #  9 pairs
D6: 5,7,1,6                              # reduction candidate for 5,7
D6: 5,7 => SOLVED
* 394165782765982134182347956641259378879634521523718649456871293218593467937426815
D6: 1,6                                  #  9 pairs
F6: 5,7,4,8                              # reduction candidate for 5,7
F6: 5,7 => CTR
* 3...64....6..8.1.44...1.9.66412.93.8...6384218..14.69..568.1.43214...86....4.6.1.
F6: 4,8                                  #  9 pairs
* PAIR E4: 5,7 COL E
E8: 5,7,9                                # reduction candidate for 5,7
E8: 5,7 => CTR
* 31..64....6..8.1.44...1.9.66412.93.8...63.421....4.6...568.1.432.4...86.1..4.6.9.
E8: 9                                    #  9 pairs
E9: 5,7,2,9                              # reduction candidate for 5,7
E9: 5,7                                  # 10 pairs
* PAIR E6: 1,4 ROW 6
H6: 1,4,9                                # reduction candidate for 1,4
H6: 9 => CTR
* 3...6.....6..8.1.4......9.66412.93.8....3..2........9..568.1.432.4....6....4.6.1.
H6: 1,4                                  #  9 pairs
* PAIR H4: 5,7 BLK 6
G5: 5,7,4,6                              # reduction candidate for 5,7
G5: 5,7 => SOLVED
* 394165782765982134182347956641259378879634521523718649456871293218593467937426815
G5: 4,6                                  #  9 pairs
I5: 5,7,1,9                              # reduction candidate for 5,7
I5: 5,7 => CTR
* 3...6.....6..8.1.4......9.66412.93.8...13.62....64.....568.1.432.4....6....4.6...
I5: 1,9                                  #  9 pairs
G6: 5,7,4,6                              # reduction candidate for 5,7
G6: 5,7 => CTR
* 39416..8..6.98.1.418..4.9.66412.93.8879534621523618749456871.93218.9.46.9..4.681.
G6: 4,6                                  #  9 pairs
I6: 5,7,1,9                              # reduction candidate for 5,7
I6: 5,7 => CTR
* 31..64....6..8.1.44...1.9.66412.93.8...63.42.....4.6...568.1.432.4....6.1..4.6.9.
I6: 1,9                                  #  9 pairs
* PAIR H4: 5,7 COL H
H1: 5,7,8                                # reduction candidate for 5,7
H1: 5,7 => CTR
* 318964....6..8.1344...1.9866412.93.8...63.421....4.6...568.1.432.4....6.1..4.6.9.
H1: 8                                    #  8 pairs
H2: 5,7,3                                # reduction candidate for 5,7
H2: 5,7                                  #  9 pairs
H3: 5,7,3,8                              # reduction candidate for 5,7
H3: 5,7                                  #  9 pairs
* PAIR H7: 4,9 ROW 7
A7: 4,9,7                                # reduction candidate for 4,9
A7: 7 => CTR
* 31..64....6..8.1.44...1.9.66412.93.8....3.42.....4.61.756891243294...8611..426.9.
A7: 4,9                                  # 11 pairs
* PAIR H7: 4,9 COL H
H6: 4,9,1                                # reduction candidate for 4,9
H6: 1 => CTR
* 3...64....6..8.1.44...1.9.66412.93.8...13..2........1..568.1.432.4....6....4.6.9.
H6: 4,9                                  # 16 pairs
* PAIR H9: 1,9 BLK 9
I8: 1,9,5,7                              # reduction candidate for 1,9
I8: 1,9 => CTR
* 31..64....6..8.1.44...1.9.66412.93.8...63.421....4.6...568.1.432.4....6.1..4.6.9.
I8: 5,7                                  # 16 pairs
I9: 1,9,2,5,7                            # reduction candidate for 1,9
I9: 1,9 => CTR
* 3...6...2.6..8.1.41...4.9.66412.93.8....3..2.....1..9.4568.1..32......6....4.6...
I9: 2,5,7                                #  8 pairs
* PAIR H9: 1,9 ROW 9
A9: 1,9,7,8                              # reduction candidate for 1,9
A9: 1,9                                  #  9 pairs
B9: 1,9,3,7,8                            # reduction candidate for 1,9
B9: 1,9 => CTR
* 3.4.6.....6..821.412..4.9.66412.93.8....3..2..32.1....4568.1.932...9.46..934.681.
B9: 3,7,8                                #  8 pairs
* PAIR H9: 1,9 COL H
H6: 1,9,4                                # reduction candidate for 1,9
H6: 1,9 => CTR
* 31..64....6..8.1.44...1.9.66412.93.8...63.421....4.6...568.1.432.4....6.1..4.6.9.
H6: 4                                    # 16 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-469-base-pr-000.dot
* REASONING
* DIS # A3: 5,7,8 => CTR => A3: 1,4
* DIS # D5: 5,7 => CTR => D5: 1,6
* DIS # F5: 5,7 => CTR => F5: 4,8
* PRF # D6: 5,7 => SOL
* DIS # F6: 5,7 => CTR => F6: 4,8
* DIS # E8: 5,7 => CTR => E8: 9
* DIS # H6: 9 => CTR => H6: 1,4
* PRF # G5: 5,7 => SOL
* DIS # I5: 5,7 => CTR => I5: 1,9
* DIS # G6: 5,7 => CTR => G6: 4,6
* DIS # I6: 5,7 => CTR => I6: 1,9
* DIS # H1: 5,7 => CTR => H1: 8
* DIS # A7: 7 => CTR => A7: 4,9
* DIS # H6: 1 => CTR => H6: 4,9
* DIS # I8: 1,9 => CTR => I8: 5,7
* DIS # I9: 1,9 => CTR => I9: 2,5,7
* DIS # B9: 1,9 => CTR => B9: 3,7,8
* DIS # H6: 1,9 => CTR => H6: 4
* CNT  18 HDP CHAINS /  40 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B6,C6,E3,E4,E6,H4,H7,H9)
* 3...6.....6..8.1.4......9.66412.93.8....3..2...........568.1..32......6....4.6...
* PAIR E3: 1,4 ROW 3
A3: 1,4,5,7,8                            # reduction candidate for 1,4
A3: 5,7,8 => CTR
* 3...6.....6..8.1.4......9.66412.93.8....3..2..........4568.1.932.....46.1..4.6...
* PAIR RESTART
* PAIR E4: 5,7 BLK 5
D5: 5,7,1,6                              # reduction candidate for 5,7
D5: 5,7 => CTR
* 39416..8..6.98.1.418..4.9.66412.93.8879534621523618749456871.93218.9.46.9..4.681.
F5: 5,7,4,8                              # reduction candidate for 5,7
F5: 5,7 => CTR
* 3...64....6..8.1.44...1.9.66412.93.8...63.421...14869..568.1.43214...86....4.6.1.
D6: 5,7,1,6                              # reduction candidate for 5,7
D6: 5,7 => SOLVED
* 394165782765982134182347956641259378879634521523718649456871293218593467937426815
* DURATION: 0:00:07.616607  START: 18:45:09.612058  END: 18:45:17.228665 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-469-base-pr-001.dot
* REASONING
* DIS # A3: 5,7,8 => CTR => A3: 1,4
* DIS A3: 1,4 # D5: 5,7 => CTR => D5: 1,6
* DIS A3: 1,4 + D5: 1,6 # F5: 5,7 => CTR => F5: 4,8
* PRF A3: 1,4 + D5: 1,6 + F5: 4,8 # D6: 5,7 => SOL
* STA A3: 1,4 + D5: 1,6 + F5: 4,8 + D6: 5,7
* CNT   4 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 469

solution: 394165782765982134182347956641259378879634521523718649456871293218593467937426815
info: 95598    FNBHWK   S8.f     29201

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

Solution

position: 394165782765982134182347956641259378879634521523718649456871293218593467937426815 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 # A3: 1,4 => UNS
* DIS # A3: 5,7,8 => CTR => A3: 1,4
* DIS # D5: 5,7 => CTR => D5: 1,6
* INC # D5: 1,6 => UNS
* DIS # F5: 5,7 => CTR => F5: 4,8
* INC # F5: 4,8 => UNS
* PRF # D6: 5,7 => SOL
* INC # D6: 1,6 => UNS
* DIS # F6: 5,7 => CTR => F6: 4,8
* INC # F6: 4,8 => UNS
* DIS # E8: 5,7 => CTR => E8: 9
* INC # E8: 9 => UNS
* INC # E9: 5,7 => UNS
* INC # H6: 1,4 => UNS
* DIS # H6: 9 => CTR => H6: 1,4
* PRF # G5: 5,7 => SOL
* INC # G5: 4,6 => UNS
* DIS # I5: 5,7 => CTR => I5: 1,9
* INC # I5: 1,9 => UNS
* DIS # G6: 5,7 => CTR => G6: 4,6
* INC # G6: 4,6 => UNS
* DIS # I6: 5,7 => CTR => I6: 1,9
* INC # I6: 1,9 => UNS
* DIS # H1: 5,7 => CTR => H1: 8
* INC # H1: 8 => UNS
* INC # H2: 5,7 => UNS
* INC # H3: 5,7 => UNS
* INC # A7: 4,9 => UNS
* DIS # A7: 7 => CTR => A7: 4,9
* INC # H6: 4,9 => UNS
* DIS # H6: 1 => CTR => H6: 4,9
* DIS # I8: 1,9 => CTR => I8: 5,7
* INC # I8: 5,7 => UNS
* DIS # I9: 1,9 => CTR => I9: 2,5,7
* INC # I9: 2,5,7 => UNS
* INC # A9: 1,9 => UNS
* DIS # B9: 1,9 => CTR => B9: 3,7,8
* INC # B9: 3,7,8 => UNS
* DIS # H6: 1,9 => CTR => H6: 4
* INC # H6: 4 => UNS
* CNT  40 HDP CHAINS /  40 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 1,4 => UNS
* DIS # A3: 5,7,8 => CTR => A3: 1,4
* DIS A3: 1,4 # D5: 5,7 => CTR => D5: 1,6
* DIS A3: 1,4 + D5: 1,6 # F5: 5,7 => CTR => F5: 4,8
* PRF A3: 1,4 + D5: 1,6 + F5: 4,8 # D6: 5,7 => SOL
* STA A3: 1,4 + D5: 1,6 + F5: 4,8 + D6: 5,7
* CNT   5 HDP CHAINS /   5 HYP OPENED