Analysis of xx-top500-489-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 4.....8......6..7.......3..9..4....6...3.7..........1....29...4..7...5...1....... initial

Autosolve

position: 4.....86.....6417.7.....34.97.41.2361..327958......4176..291784..7...5.1.1....6.3 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C2: 3,5 => CTR => C2: 2,8,9
* DIS # D3: 5,8 => CTR => D3: 1,9
* DIS # B3: 5,8 => CTR => B3: 2,6,9
* PRF # F1: 3 => SOL
* PRF # B3: 2,9 => SOL
* DIS # C3: 2,9 => CTR => C3: 1,5,6,8
* DIS # C6: 5,8 => CTR => C6: 2,3
* DIS # B6: 3,5 => CTR => B6: 2,8
* DIS # C6: 3,5 => CTR => C6: 2,8
* DIS # C6: 5,8 => CTR => C6: 2,3
* DIS # B6: 3,5 => CTR => B6: 2,8
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* DIS # C6: 3,5 => CTR => C6: 2,8
* PRF # D9: 7 => SOL
* CNT  14 HDP CHAINS /  37 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 # C2: 3,5 => CTR => C2: 2,8,9
* DIS C2: 2,8,9 # B2: 2,8,9 => CTR => B2: 3,5
* DIS C2: 2,8,9 + B2: 3,5 # F1: 2,9 => CTR => F1: 3
* PRF C2: 2,8,9 + B2: 3,5 + F1: 3 => SOL
* STA C2: 2,8,9 + B2: 3,5 + F1: 3
* CNT   4 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

4.....8......6..7.......3..9..4....6...3.7..........1....29...4..7...5...1....... initial
4.....86.....6417.7.....34.97.41.2361..327958......4176..291784..7...5.1.1....6.3 autosolve
421573869538964172796182345975418236164327958382659417653291784247836591819745623 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (25)
A2: 3,5
E1: 3,7
E3: 5,8
F3: 2,9
C4: 5,8
B5: 4,6
C5: 4,6
A6: 3,5
F4: 5,8
D6: 6,9
E6: 5,8
F6: 6,9
B7: 3,5
C7: 3,5
A8: 2,8
B8: 4,9
A9: 2,8
C9: 4,9
D8: 6,8
E8: 3,4
F8: 3,6
E9: 4,7
F9: 5,8
H8: 2,9
H9: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C1,C3: 1.. / C1 = 1  => 25 pairs (_) / C3 = 1  =>  0 pairs (X)
D1,D3: 1.. / D1 = 1  =>  0 pairs (X) / D3 = 1  => 25 pairs (_)
C1,D1: 1.. / C1 = 1  => 25 pairs (_) / D1 = 1  =>  0 pairs (X)
C3,D3: 1.. / C3 = 1  =>  0 pairs (X) / D3 = 1  => 25 pairs (_)
F1,F3: 2.. / F1 = 2  =>  0 pairs (X) / F3 = 2  => 26 pairs (_)
B6,C6: 2.. / B6 = 2  => 26 pairs (_) / C6 = 2  => 25 pairs (_)
A8,A9: 2.. / A8 = 2  =>  0 pairs (*) / A9 = 2  =>  0 pairs (X)
H8,H9: 2.. / H8 = 2  => 14 pairs (_) / H9 = 2  =>  0 pairs (*)
A8,H8: 2.. / A8 = 2  =>  0 pairs (*) / H8 = 2  =>  0 pairs (X)
A9,H9: 2.. / A9 = 2  => 14 pairs (_) / H9 = 2  =>  0 pairs (*)
E1,F1: 3.. / E1 = 3  => 14 pairs (_) / F1 = 3  =>  0 pairs (*)
B7,C7: 3.. / B7 = 3  =>  0 pairs (X) / C7 = 3  => 24 pairs (_)
E8,F8: 3.. / E8 = 3  =>  0 pairs (*) / F8 = 3  =>  0 pairs (X)
A2,A6: 3.. / A2 = 3  =>  0 pairs (X) / A6 = 3  => 28 pairs (_)
E1,E8: 3.. / E1 = 3  => 14 pairs (_) / E8 = 3  =>  0 pairs (*)
F1,F8: 3.. / F1 = 3  =>  0 pairs (*) / F8 = 3  =>  0 pairs (X)
B5,C5: 4.. / B5 = 4  => 14 pairs (_) / C5 = 4  =>  0 pairs (*)
B8,C9: 4.. / B8 = 4  =>  0 pairs (*) / C9 = 4  =>  0 pairs (X)
E8,E9: 4.. / E8 = 4  => 14 pairs (_) / E9 = 4  =>  0 pairs (*)
B8,E8: 4.. / B8 = 4  =>  0 pairs (*) / E8 = 4  =>  0 pairs (X)
C9,E9: 4.. / C9 = 4  => 14 pairs (_) / E9 = 4  =>  0 pairs (*)
B5,B8: 4.. / B5 = 4  => 14 pairs (_) / B8 = 4  =>  0 pairs (*)
C5,C9: 4.. / C5 = 4  =>  0 pairs (*) / C9 = 4  =>  0 pairs (X)
F4,E6: 5.. / F4 = 5  =>  0 pairs (X) / E6 = 5  =>  0 pairs (_)
B7,C7: 5.. / B7 = 5  => 24 pairs (_) / C7 = 5  =>  0 pairs (X)
D9,F9: 5.. / D9 = 5  =>  0 pairs (X) / F9 = 5  =>  0 pairs (_)
C4,F4: 5.. / C4 = 5  =>  0 pairs (*) / F4 = 5  =>  0 pairs (X)
A2,A6: 5.. / A2 = 5  => 28 pairs (_) / A6 = 5  =>  0 pairs (X)
E3,E6: 5.. / E3 = 5  =>  0 pairs (X) / E6 = 5  =>  0 pairs (_)
F4,F9: 5.. / F4 = 5  =>  0 pairs (X) / F9 = 5  =>  0 pairs (_)
B3,C3: 6.. / B3 = 6  => 14 pairs (_) / C3 = 6  =>  0 pairs (*)
B5,C5: 6.. / B5 = 6  =>  0 pairs (*) / C5 = 6  =>  0 pairs (X)
D6,F6: 6.. / D6 = 6  =>  0 pairs (*) / F6 = 6  =>  0 pairs (X)
D8,F8: 6.. / D8 = 6  => 14 pairs (_) / F8 = 6  =>  0 pairs (*)
B3,B5: 6.. / B3 = 6  => 14 pairs (_) / B5 = 6  =>  0 pairs (*)
C3,C5: 6.. / C3 = 6  =>  0 pairs (*) / C5 = 6  =>  0 pairs (X)
D6,D8: 6.. / D6 = 6  =>  0 pairs (*) / D8 = 6  =>  0 pairs (X)
F6,F8: 6.. / F6 = 6  => 14 pairs (_) / F8 = 6  =>  0 pairs (*)
D1,E1: 7.. / D1 = 7  => 14 pairs (_) / E1 = 7  =>  0 pairs (*)
D9,E9: 7.. / D9 = 7  =>  0 pairs (*) / E9 = 7  =>  0 pairs (X)
D1,D9: 7.. / D1 = 7  => 14 pairs (_) / D9 = 7  =>  0 pairs (*)
E1,E9: 7.. / E1 = 7  =>  0 pairs (*) / E9 = 7  =>  0 pairs (X)
F4,E6: 8.. / F4 = 8  =>  0 pairs (*) / E6 = 8  =>  0 pairs (X)
A8,A9: 8.. / A8 = 8  => 14 pairs (_) / A9 = 8  =>  0 pairs (*)
C4,F4: 8.. / C4 = 8  =>  0 pairs (X) / F4 = 8  =>  0 pairs (_)
A8,D8: 8.. / A8 = 8  => 14 pairs (_) / D8 = 8  =>  0 pairs (*)
E3,E6: 8.. / E3 = 8  =>  0 pairs (*) / E6 = 8  =>  0 pairs (X)
F4,F9: 8.. / F4 = 8  =>  0 pairs (*) / F9 = 8  =>  0 pairs (X)
D6,F6: 9.. / D6 = 9  => 14 pairs (_) / F6 = 9  =>  0 pairs (*)
B8,C9: 9.. / B8 = 9  => 14 pairs (_) / C9 = 9  =>  0 pairs (*)
H8,H9: 9.. / H8 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
B8,H8: 9.. / B8 = 9  => 14 pairs (_) / H8 = 9  =>  0 pairs (*)
C9,H9: 9.. / C9 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
* DURATION: 0:01:56.617866  START: 19:21:47.143505  END: 19:23:43.761371 2017-05-04
* CP COUNT: (53)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A6,A8,A9,B5,B7,B8,C4,C5,C7,C9,D6,D8,E1,E3,E6,E8,E9,F3,F4,F6,F8,F9,H8,H9)
* 4.....86.....6417.7.....34.97.41.2361..327958......4176..291784..7...5.1.1....6.3
* PAIR A2: 3,5 BLK 1
B2: 3,5,2,8,9                            # reduction candidate for 3,5
B2: 3,5                                  # 32 pairs
C2: 3,5,2,8,9                            # reduction candidate for 3,5
C2: 3,5 => CTR
* 4..73.865...86417.78615.34.978415236164327958..29864176..291784847...5.1.1.5786.3
C2: 2,8,9                                # 25 pairs
* PAIR E3: 5,8 BLK 2
D2: 5,8,9                                # reduction candidate for 5,8
D2: 5,8                                  # 27 pairs
D3: 5,8,1,9                              # reduction candidate for 5,8
D3: 5,8 => CTR
* 4..17386.....6417.7.1..234.97.41.2361.6327958.....94176..291784..7.365.1.14...6.3
D3: 1,9                                  # 26 pairs
* PAIR E3: 5,8 ROW 3
B3: 5,8,2,6,9                            # reduction candidate for 5,8
B3: 5,8 => CTR
* 4.1.7386.....6417.7.61823499754182361643279583..65941765.291784247836591819745623
B3: 2,6,9                                # 25 pairs
C3: 5,8,1,2,6,9                          # reduction candidate for 5,8
C3: 5,8                                  # 12 pairs
* PAIR F3: 2,9 BLK 2
F1: 2,9,3                                # reduction candidate for 2,9
F1: 3 => SOLVED
* 421573869538964172796182345975418236164327958382659417653291784247836591819745623
F1: 2,9                                  # 14 pairs
* PAIR F3: 2,9 ROW 3
B3: 2,9,5,6,8                            # reduction candidate for 2,9
B3: 2,9 => SOLVED
* 421573869538964172796182345975418236164327958382659417653291784247836591819745623
B3: 5,6,8                                # 25 pairs
C3: 2,9,1,5,6,8                          # reduction candidate for 2,9
C3: 2,9 => CTR
* 4.173.86.5..96417276918234597.418236146327958....5.4176..291784.97.43521214875693
C3: 1,5,6,8                              # 25 pairs
I3: 2,9,5                                # reduction candidate for 2,9
I3: 2,9                                  # 26 pairs
* PAIR C4: 5,8 BLK 4
B6: 5,8,2,3                              # reduction candidate for 5,8
B6: 5,8                                  # 30 pairs
C6: 5,8,2,3                              # reduction candidate for 5,8
C6: 5,8 => CTR
* 49....86.53..6417.78615.34.97.415236164327958325.8.417653291784.47.36591.195..6.3
C6: 2,3                                  # 26 pairs
* PAIR C4: 5,8 COL C
C2: 5,8,2,3,9                            # reduction candidate for 5,8
C2: 5,8                                  # 31 pairs
C3: 5,8,1,2,6,9                          # reduction candidate for 5,8
C3: 5,8                                  # 12 pairs
* PAIR A6: 3,5 BLK 4
B6: 3,5,2,8                              # reduction candidate for 3,5
B6: 3,5 => CTR
* 4.173.86....86417.78615.34.9784152361..327958..29864176..291784897643521214578693
B6: 2,8                                  # 26 pairs
C6: 3,5,2,8                              # reduction candidate for 3,5
C6: 3,5 => CTR
* 45173.86.38..6417.7..15.34.9784152361..327958.2.9864176..291784897643521214578693
C6: 2,8                                  # 26 pairs
* PAIR E6: 5,8 ROW 6
B6: 5,8,2,3                              # reduction candidate for 5,8
B6: 5,8                                  # 30 pairs
C6: 5,8,2,3                              # reduction candidate for 5,8
C6: 5,8 => CTR
* 49....86.53..6417.78615.34.97.415236164327958325.8.417653291784.47.36591.195..6.3
C6: 2,3                                  # 26 pairs
* PAIR B7: 3,5 COL B
B2: 3,5,2,8,9                            # reduction candidate for 3,5
B2: 3,5                                  # 32 pairs
B6: 3,5,2,8                              # reduction candidate for 3,5
B6: 3,5 => CTR
* 4.173.86....86417.78615.34.9784152361..327958..29864176..291784897643521214578693
B6: 2,8                                  # 26 pairs
* PAIR C7: 3,5 COL C
C2: 3,5,2,8,9                            # reduction candidate for 3,5
C2: 3,5 => CTR
* 4..73.865...86417.78615.34.978415236164327958..29864176..291784847...5.1.1.5786.3
C2: 2,8,9                                # 25 pairs
C6: 3,5,2,8                              # reduction candidate for 3,5
C6: 3,5 => CTR
* 45173.86.38..6417.7..15.34.9784152361..327958.2.9864176..291784897643521214578693
C6: 2,8                                  # 26 pairs
* PAIR F9: 5,8 BLK 8
D9: 5,8,7                                # reduction candidate for 5,8
D9: 7 => SOLVED
* 421573869538964172796182345975418236164327958382659417653291784247836591819745623
D9: 5,8                                  # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-489-base-pr-000.dot
* REASONING
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* DIS # D3: 5,8 => CTR => D3: 1,9
* DIS # B3: 5,8 => CTR => B3: 2,6,9
* PRF # F1: 3 => SOL
* PRF # B3: 2,9 => SOL
* DIS # C3: 2,9 => CTR => C3: 1,5,6,8
* DIS # C6: 5,8 => CTR => C6: 2,3
* DIS # B6: 3,5 => CTR => B6: 2,8
* DIS # C6: 3,5 => CTR => C6: 2,8
* DIS # C6: 5,8 => CTR => C6: 2,3
* DIS # B6: 3,5 => CTR => B6: 2,8
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* DIS # C6: 3,5 => CTR => C6: 2,8
* PRF # D9: 7 => SOL
* CNT  14 HDP CHAINS /  37 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A6,A8,A9,B5,B7,B8,C4,C5,C7,C9,D6,D8,E1,E3,E6,E8,E9,F3,F4,F6,F8,F9,H8,H9)
* 4.....86.....6417.7.....34.97.41.2361..327958......4176..291784..7...5.1.1....6.3
* PAIR A2: 3,5 BLK 1
B2: 3,5,2,8,9                            # reduction candidate for 3,5
B2: 3,5                                  # 32 pairs
C2: 3,5,2,8,9                            # reduction candidate for 3,5
C2: 3,5 => CTR
* 4..73.865...86417.78615.34.978415236164327958..29864176..291784847...5.1.1.5786.3
* RESTART
* PAIR A2: 3,5 BLK 1
B2: 3,5,2,8,9                            # reduction candidate for 3,5
B2: 2,8,9 => CTR
* 4.173.86.3.986417578615.34.9784152361..3279585..9864176..291784897643521214578693
* PAIR F3: 2,9 BLK 2
F1: 2,9,3                                # reduction candidate for 2,9
F1: 2,9 => CTR
* 4..73.865....6417.7..15.34.97.415236146327958....864176..291784.97.435.1.14.7.693
F1: 3 => SOLVED
* 421573869538964172796182345975418236164327958382659417653291784247836591819745623
* DURATION: 0:00:08.794395  START: 19:24:27.610049  END: 19:24:36.404444 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-489-base-pr-001.dot
* REASONING
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* DIS C2: 2,8,9 # B2: 2,8,9 => CTR => B2: 3,5
* DIS C2: 2,8,9 + B2: 3,5 # F1: 2,9 => CTR => F1: 3
* PRF C2: 2,8,9 + B2: 3,5 + F1: 3 => SOL
* STA C2: 2,8,9 + B2: 3,5 + F1: 3
* CNT   4 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 489

solution: 421573869538964172796182345975418236164327958382659417653291784247836591819745623
info: 96228    FNBTXYK  S8.f     30525

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

Solution

position: 421573869538964172796182345975418236164327958382659417653291784247836591819745623 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 # B2: 3,5 => UNS
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* INC # C2: 2,8,9 => UNS
* INC # D2: 5,8 => UNS
* DIS # D3: 5,8 => CTR => D3: 1,9
* INC # D3: 1,9 => UNS
* DIS # B3: 5,8 => CTR => B3: 2,6,9
* INC # B3: 2,6,9 => UNS
* INC # C3: 5,8 => UNS
* INC # F1: 2,9 => UNS
* PRF # F1: 3 => SOL
* PRF # B3: 2,9 => SOL
* INC # B3: 5,6,8 => UNS
* DIS # C3: 2,9 => CTR => C3: 1,5,6,8
* INC # C3: 1,5,6,8 => UNS
* INC # I3: 2,9 => UNS
* INC # B6: 5,8 => UNS
* DIS # C6: 5,8 => CTR => C6: 2,3
* INC # C6: 2,3 => UNS
* INC # C2: 5,8 => UNS
* INC # C3: 5,8 => UNS
* DIS # B6: 3,5 => CTR => B6: 2,8
* INC # B6: 2,8 => UNS
* DIS # C6: 3,5 => CTR => C6: 2,8
* INC # C6: 2,8 => UNS
* INC # B6: 5,8 => UNS
* DIS # C6: 5,8 => CTR => C6: 2,3
* INC # C6: 2,3 => UNS
* INC # B2: 3,5 => UNS
* DIS # B6: 3,5 => CTR => B6: 2,8
* INC # B6: 2,8 => UNS
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* INC # C2: 2,8,9 => UNS
* DIS # C6: 3,5 => CTR => C6: 2,8
* INC # C6: 2,8 => UNS
* INC # D9: 5,8 => UNS
* PRF # D9: 7 => SOL
* CNT  37 HDP CHAINS /  37 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B2: 3,5 => UNS
* DIS # C2: 3,5 => CTR => C2: 2,8,9
* INC C2: 2,8,9 # B2: 3,5 => UNS
* DIS C2: 2,8,9 # B2: 2,8,9 => CTR => B2: 3,5
* DIS C2: 2,8,9 + B2: 3,5 # F1: 2,9 => CTR => F1: 3
* PRF C2: 2,8,9 + B2: 3,5 + F1: 3 => SOL
* STA C2: 2,8,9 + B2: 3,5 + F1: 3
* CNT   6 HDP CHAINS /   5 HYP OPENED