Analysis of xx-top500-422-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6.27........8..13........9.4.....7...3..9........1....5..4..6...1.....2.......... initial

Autosolve

position: 692731...7..829136.8..4.2974.....7...3..9........1....5..4..6...1.9...2....1..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D4: 5,6 => CTR => D4: 2,3
* DIS # F4: 5,6 => CTR => F4: 8
* DIS # F9: 5,6 => CTR => F9: 2,3,8
* DIS # B9: 2,7 => CTR => B9: 4,6
* DIS # B6: 2,7 => CTR => B6: 5,6
* DIS # C7: 3,8 => CTR => C7: 7,9
* PRF # C8: 3,8 => SOL
* DIS # A9: 3,8 => CTR => A9: 2,9
* DIS # E9: 7,8 => CTR => E9: 5,6
* DIS # C7: 7,8 => CTR => C7: 3,9
* DIS # H7: 7,8 => CTR => H7: 1
* CNT  11 HDP CHAINS /  30 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 # D4: 5,6 => CTR => D4: 2,3
* DIS D4: 2,3 # F4: 5,6 => CTR => F4: 8
* DIS D4: 2,3 + F4: 8 # F9: 5,6 => CTR => F9: 2,3
* DIS D4: 2,3 + F4: 8 + F9: 2,3 # B9: 2,7 => CTR => B9: 4,6
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 # B6: 2,7 => CTR => B6: 5,6
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 # H5: 4,5 => CTR => H5: 6
* PRF D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6 => SOL
* STA D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6
* CNT   7 HDP CHAINS /  13 HYP OPENED

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

Details

Positions

6.27........8..13........9.4.....7...3..9........1....5..4..6...1.....2.......... initial
692731...7..829136.8..4.2974.....7...3..9........1....5..4..6...1.9...2....1..... autosolve
692731845754829136183645297421368759835297461967514382579482613318976524246153978 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
B2: 4,5
C2: 4,5
A3: 1,3
C3: 1,3
D3: 5,6
F3: 5,6
F5: 4,7
F6: 4,7
B7: 2,7
A8: 3,8
E7: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A3,C3: 1.. / A3 = 1  => 10 pairs (_) / C3 = 1  => 10 pairs (_)
H7,I7: 1.. / H7 = 1  => 14 pairs (_) / I7 = 1  =>  0 pairs (X)
A3,A5: 1.. / A3 = 1  => 10 pairs (_) / A5 = 1  => 10 pairs (_)
F7,F9: 2.. / F7 = 2  => 14 pairs (_) / F9 = 2  =>  0 pairs (X)
B7,F7: 2.. / B7 = 2  =>  0 pairs (X) / F7 = 2  => 14 pairs (_)
A3,C3: 3.. / A3 = 3  => 10 pairs (_) / C3 = 3  => 10 pairs (_)
D4,D6: 3.. / D4 = 3  => 11 pairs (_) / D6 = 3  =>  0 pairs (X)
D4,I4: 3.. / D4 = 3  => 11 pairs (_) / I4 = 3  =>  0 pairs (X)
B2,C2: 4.. / B2 = 4  =>  9 pairs (_) / C2 = 4  => 10 pairs (_)
F5,F6: 4.. / F5 = 4  => 14 pairs (_) / F6 = 4  =>  9 pairs (_)
B2,B9: 4.. / B2 = 4  =>  9 pairs (_) / B9 = 4  => 10 pairs (_)
B2,C2: 5.. / B2 = 5  => 10 pairs (_) / C2 = 5  =>  9 pairs (_)
D3,F3: 5.. / D3 = 5  => 16 pairs (_) / F3 = 5  => 14 pairs (_)
D3,F3: 6.. / D3 = 6  => 14 pairs (_) / F3 = 6  => 16 pairs (_)
F5,F6: 7.. / F5 = 7  =>  9 pairs (_) / F6 = 7  => 14 pairs (_)
H7,H9: 7.. / H7 = 7  =>  0 pairs (X) / H9 = 7  => 12 pairs (_)
C5,F5: 7.. / C5 = 7  => 14 pairs (_) / F5 = 7  =>  9 pairs (_)
C8,E8: 7.. / C8 = 7  =>  0 pairs (X) / E8 = 7  => 14 pairs (_)
E4,F4: 8.. / E4 = 8  =>  0 pairs (X) / F4 = 8  => 13 pairs (_)
C4,I4: 9.. / C4 = 9  =>  0 pairs (X) / I4 = 9  => 14 pairs (_)
C7,I7: 9.. / C7 = 9  => 14 pairs (_) / I7 = 9  =>  0 pairs (X)
A6,A9: 9.. / A6 = 9  => 14 pairs (_) / A9 = 9  =>  0 pairs (X)
G6,G9: 9.. / G6 = 9  =>  0 pairs (X) / G9 = 9  => 14 pairs (_)
* DURATION: 0:00:36.891989  START: 17:13:33.946153  END: 17:14:10.838142 2017-05-04
* CP COUNT: (23)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B2,B7,C2,C3,D3,E7,F3,F5,F6)
* 692731...7..829136.8..4.2974.....7...3..9........1....5..4..6...1.9...2....1.....
* PAIR D3: 5,6 COL D
D4: 5,6,2,3                              # reduction candidate for 5,6
D4: 5,6 => CTR
* 692731...7..829136.8..4.297429...713.3.29....8..31....5..4..6...1.9...2....1.....
D4: 2,3                                  # 12 pairs
D5: 5,6,2                                # reduction candidate for 5,6
D5: 5,6                                  # 14 pairs
D6: 5,6,2,3                              # reduction candidate for 5,6
D6: 5,6                                  # 17 pairs
* PAIR F3: 5,6 COL F
F4: 5,6,8                                # reduction candidate for 5,6
F4: 5,6 => CTR
* 692731...7..829136.8..4.2974.9.8.71..3..97....7..14...52.47.68..1796..2....152.7.
F4: 8                                    # 13 pairs
F8: 5,6,3,8                              # reduction candidate for 5,6
F8: 5,6                                  # 15 pairs
F9: 5,6,2,3,8                            # reduction candidate for 5,6
F9: 5,6 => CTR
* 692731...7..829136.8..4.2974....87...3..9........1....57.48261.816973.2....1...7.
F9: 2,3,8                                # 11 pairs
* PAIR B7: 2,7 BLK 7
B9: 2,7,4,6                              # reduction candidate for 2,7
B9: 2,7 => CTR
* 692731...745829136.8..4.2974.9...71..3..9........1....5..4..6...1.9...2....1.....
B9: 4,6                                  # 12 pairs
* PAIR B7: 2,7 COL B
B6: 2,7,5,6                              # reduction candidate for 2,7
B6: 2,7 => CTR
* 692731...7..829136.8..4.2974.9...71..3..9........1....5..4..6...1.9...2....1.....
B6: 5,6                                  # 16 pairs
* PAIR A8: 3,8 BLK 7
C7: 3,8,7,9                              # reduction candidate for 3,8
C7: 3,8 => CTR
* 692731...7..829136.8..4.2974.93..7.1.3..9...22...1.9.35..4..619.1.9...2.9..1...7.
C7: 7,9                                  # 12 pairs
C8: 3,8,4,6,7                            # reduction candidate for 3,8
C8: 3,8 => SOLVED
* 692731845754829136183645297421368759835297461967514382579482613318976524246153978
C8: 4,6,7                                # 11 pairs
A9: 3,8,2,9                              # reduction candidate for 3,8
A9: 3,8 => CTR
* 692731...7..829136.8..4.2974.....7.923..9....9...1...25.94..6...1.9...2....1..9..
A9: 2,9                                  # 12 pairs
C9: 3,8,4,6,7,9                          # reduction candidate for 3,8
C9: 3,8                                  # 16 pairs
* PAIR A8: 3,8 ROW 8
F8: 3,8,5,6                              # reduction candidate for 3,8
F8: 3,8                                  # 19 pairs
G8: 3,8,4,5                              # reduction candidate for 3,8
G8: 3,8                                  # 17 pairs
I8: 3,8,4,5                              # reduction candidate for 3,8
I8: 3,8                                  # 19 pairs
* PAIR E7: 7,8 BLK 8
E8: 7,8,5,6                              # reduction candidate for 7,8
E8: 7,8                                  # 15 pairs
E9: 7,8,5,6                              # reduction candidate for 7,8
E9: 7,8 => CTR
* 692731...7..829136.83.4.2974.9..871..31.97....7..14...5284.36...179...2....1.2...
E9: 5,6                                  # 12 pairs
* PAIR E7: 7,8 ROW 7
C7: 7,8,3,9                              # reduction candidate for 7,8
C7: 7,8 => CTR
* 692731...7..829136.8..4.2974.9...7.1.3..9........1.9.352.4.3619.1.9...2.9..1.2.7.
C7: 3,9                                  # 12 pairs
H7: 7,8,1                                # reduction candidate for 7,8
H7: 7,8 => CTR
* 692731...7..829136.8..4.2974.....7.9.3..9....9...1....5294.36.1.1.9...2....1.29..
H7: 1                                    # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-422-base-pr-000.dot
* REASONING
* DIS # D4: 5,6 => CTR => D4: 2,3
* DIS # F4: 5,6 => CTR => F4: 8
* DIS # F9: 5,6 => CTR => F9: 2,3,8
* DIS # B9: 2,7 => CTR => B9: 4,6
* DIS # B6: 2,7 => CTR => B6: 5,6
* DIS # C7: 3,8 => CTR => C7: 7,9
* PRF # C8: 3,8 => SOL
* DIS # A9: 3,8 => CTR => A9: 2,9
* DIS # E9: 7,8 => CTR => E9: 5,6
* DIS # C7: 7,8 => CTR => C7: 3,9
* DIS # H7: 7,8 => CTR => H7: 1
* CNT  11 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B2,B7,C2,C3,D3,E7,F3,F5,F6)
* 692731...7..829136.8..4.2974.....7...3..9........1....5..4..6...1.9...2....1.....
* PAIR D3: 5,6 COL D
D4: 5,6,2,3                              # reduction candidate for 5,6
D4: 5,6 => CTR
* 692731...7..829136.8..4.297429...713.3.29....8..31....5..4..6...1.9...2....1.....
D5: 5,6,2                                # reduction candidate for 5,6
D5: 5,6                                  # 14 pairs
D6: 5,6,2,3                              # reduction candidate for 5,6
D6: 5,6                                  # 17 pairs
* PAIR RESTART
* PAIR D3: 5,6 COL D
D5: 5,6,2                                # reduction candidate for 5,6
D5: 5,6                                  # 14 pairs
D6: 5,6,2,3                              # reduction candidate for 5,6
D6: 5,6                                  # 17 pairs
* PAIR F3: 5,6 COL F
F4: 5,6,8                                # reduction candidate for 5,6
F4: 5,6 => CTR
* 692731...7..829136.8..4.2974.9.8.71..3..97....7..14...52.47.68..1796..2....152.7.
F8: 5,6,3                                # reduction candidate for 5,6
F8: 5,6                                  # 16 pairs
F9: 5,6,2,3                              # reduction candidate for 5,6
F9: 5,6 => CTR
* 692731...7..829136.8..4.2974....87...3..9........1....57.48261.816973.2....1...7.
* RESTART
* PAIR RESTART
* PAIR B7: 2,7 BLK 7
B9: 2,7,4,6                              # reduction candidate for 2,7
B9: 2,7 => CTR
* 692731...745829136.8..4.2974.9..871..3..9........1....5..4..6...1.9...2....1.....
* PAIR B7: 2,7 COL B
B6: 2,7,5,6                              # reduction candidate for 2,7
B6: 2,7 => CTR
* 692731...7..829136.8..4.2974.9..871..3..9........1....5..4..6...1.9...2....1.....
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (B2,B6,B9,C2,C5,D3,D6,E4,E9,F3,F8,G5,H1,H4)
* 692731...7..829136183.4.2974213.87.983.297..19.7.1438257948261331.97..2.2..1.397.
* PAIR H1: 4,5 BLK 3
G1: 4,5,8                                # reduction candidate for 4,5
G1: 4,5                                  # 18 pairs
I1: 4,5,8                                # reduction candidate for 4,5
I1: 4,5                                  # 16 pairs
* PAIR H1: 4,5 COL H
H5: 4,5,6                                # reduction candidate for 4,5
H5: 4,5 => CTR
* 692731...7..829136183.4.2974213.8769836297..195761438257948261331.976.2.26.15397.
H5: 6 => SOLVED
* 692731845754829136183645297421368759835297461967514382579482613318976524246153978
* DURATION: 0:00:17.958487  START: 17:14:36.458440  END: 17:14:54.416927 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-422-base-pr-001.dot
* REASONING
* DIS # D4: 5,6 => CTR => D4: 2,3
* DIS D4: 2,3 # F4: 5,6 => CTR => F4: 8
* DIS D4: 2,3 + F4: 8 # F9: 5,6 => CTR => F9: 2,3
* DIS D4: 2,3 + F4: 8 + F9: 2,3 # B9: 2,7 => CTR => B9: 4,6
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 # B6: 2,7 => CTR => B6: 5,6
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 # H5: 4,5 => CTR => H5: 6
* PRF D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6 => SOL
* STA D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6
* CNT   7 HDP CHAINS /  13 HYP OPENED

Header Info

Top 500 Minimum 17 422

solution: 692731845754829136183645297421368759835297461967514382579482613318976524246153978
info: 95114    FNBHWXK  S8.f     35424

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

Solution

position: 692731845754829136183645297421368759835297461967514382579482613318976524246153978 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 # D4: 5,6 => CTR => D4: 2,3
* INC # D4: 2,3 => UNS
* INC # D5: 5,6 => UNS
* INC # D6: 5,6 => UNS
* DIS # F4: 5,6 => CTR => F4: 8
* INC # F4: 8 => UNS
* INC # F8: 5,6 => UNS
* DIS # F9: 5,6 => CTR => F9: 2,3,8
* INC # F9: 2,3,8 => UNS
* DIS # B9: 2,7 => CTR => B9: 4,6
* INC # B9: 4,6 => UNS
* DIS # B6: 2,7 => CTR => B6: 5,6
* INC # B6: 5,6 => UNS
* DIS # C7: 3,8 => CTR => C7: 7,9
* INC # C7: 7,9 => UNS
* PRF # C8: 3,8 => SOL
* INC # C8: 4,6,7 => UNS
* DIS # A9: 3,8 => CTR => A9: 2,9
* INC # A9: 2,9 => UNS
* INC # C9: 3,8 => UNS
* INC # F8: 3,8 => UNS
* INC # G8: 3,8 => UNS
* INC # I8: 3,8 => UNS
* INC # E8: 7,8 => UNS
* DIS # E9: 7,8 => CTR => E9: 5,6
* INC # E9: 5,6 => UNS
* DIS # C7: 7,8 => CTR => C7: 3,9
* INC # C7: 3,9 => UNS
* DIS # H7: 7,8 => CTR => H7: 1
* INC # H7: 1 => UNS
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D4: 5,6 => CTR => D4: 2,3
* INC D4: 2,3 # D5: 5,6 => UNS
* INC D4: 2,3 # D6: 5,6 => UNS
* INC D4: 2,3 # D5: 5,6 => UNS
* INC D4: 2,3 # D6: 5,6 => UNS
* DIS D4: 2,3 # F4: 5,6 => CTR => F4: 8
* INC D4: 2,3 + F4: 8 # F8: 5,6 => UNS
* DIS D4: 2,3 + F4: 8 # F9: 5,6 => CTR => F9: 2,3
* DIS D4: 2,3 + F4: 8 + F9: 2,3 # B9: 2,7 => CTR => B9: 4,6
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 # B6: 2,7 => CTR => B6: 5,6
* INC D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 # G1: 4,5 => UNS
* INC D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 # I1: 4,5 => UNS
* DIS D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 # H5: 4,5 => CTR => H5: 6
* PRF D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6 => SOL
* STA D4: 2,3 + F4: 8 + F9: 2,3 + B9: 4,6 + B6: 5,6 + H5: 6
* CNT  14 HDP CHAINS /  13 HYP OPENED