Analysis of xx-top500-368-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 1.4...5.......27.....3......736...........1...2.......8...4..2.....1...6.......3. initial

Autosolve

position: 134.6.5.2...1.27432.73.461..736.12.....23.1...2147.3..8...4392.3.2.1...67...26.3. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # H6: 8,9 => SOL
* DIS # I4: 8,9 => CTR => I4: 4,5
* PRF # F6: 5 => SOL
* DIS # I4: 8,9 => CTR => I4: 4,5
* PRF # F6: 5,9 => SOL
* DIS # F6: 8 => CTR => F6: 5,9
* DIS # B7: 5,6 => CTR => B7: 1
* DIS # I7: 1 => CTR => I7: 5,7
* DIS # I7: 1 => CTR => I7: 5,7
* CNT   9 HDP CHAINS /  48 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 # H6: 8,9 => SOL
* STA H6: 8,9
* CNT   1 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

1.4...5.......27.....3......736...........1...2.......8...4..2.....1...6.......3. initial
134.6.5.2...1.27432.73.461..736.12.....23.1...2147.3..8...4392.3.2.1...67...26.3. autosolve
134867592568192743297354618973681254485239167621475389816743925352918476749526831 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
H1: 8,9
I3: 8,9
E4: 8,9
F5: 5,9
C7: 5,6
C9: 5,9
D7: 5,7
G8: 4,8
H8: 5,7
G9: 4,8
I9: 1,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B7,B9: 1.. / B7 = 1  => 10 pairs (_) / B9 = 1  =>  0 pairs (X)
I7,I9: 1.. / I7 = 1  =>  0 pairs (X) / I9 = 1  => 10 pairs (_)
B7,I7: 1.. / B7 = 1  => 10 pairs (_) / I7 = 1  =>  0 pairs (X)
B9,I9: 1.. / B9 = 1  =>  0 pairs (X) / I9 = 1  => 10 pairs (_)
A4,A5: 4.. / A4 = 4  => 12 pairs (_) / A5 = 4  => 12 pairs (_)
I4,I5: 4.. / I4 = 4  => 12 pairs (_) / I5 = 4  => 12 pairs (_)
B8,B9: 4.. / B8 = 4  => 11 pairs (_) / B9 = 4  => 10 pairs (_)
G8,G9: 4.. / G8 = 4  => 10 pairs (_) / G9 = 4  => 11 pairs (_)
A4,I4: 4.. / A4 = 4  => 12 pairs (_) / I4 = 4  => 12 pairs (_)
A5,I5: 4.. / A5 = 4  => 12 pairs (_) / I5 = 4  => 12 pairs (_)
B8,G8: 4.. / B8 = 4  => 11 pairs (_) / G8 = 4  => 10 pairs (_)
B9,G9: 4.. / B9 = 4  => 10 pairs (_) / G9 = 4  => 11 pairs (_)
E2,E3: 5.. / E2 = 5  => 15 pairs (_) / E3 = 5  => 13 pairs (_)
F5,F6: 5.. / F5 = 5  => 12 pairs (_) / F6 = 5  =>  0 pairs (*)
B3,E3: 5.. / B3 = 5  => 15 pairs (_) / E3 = 5  => 13 pairs (_)
H5,H6: 6.. / H5 = 6  => 15 pairs (_) / H6 = 6  => 12 pairs (_)
B7,C7: 6.. / B7 = 6  =>  0 pairs (X) / C7 = 6  => 11 pairs (_)
A6,H6: 6.. / A6 = 6  => 15 pairs (_) / H6 = 6  => 12 pairs (_)
D1,F1: 7.. / D1 = 7  => 15 pairs (_) / F1 = 7  => 13 pairs (_)
H5,I5: 7.. / H5 = 7  => 13 pairs (_) / I5 = 7  => 14 pairs (_)
I7,H8: 7.. / I7 = 7  => 13 pairs (_) / H8 = 7  => 14 pairs (_)
D7,I7: 7.. / D7 = 7  => 14 pairs (_) / I7 = 7  => 13 pairs (_)
F1,F8: 7.. / F1 = 7  => 13 pairs (_) / F8 = 7  => 15 pairs (_)
H5,H8: 7.. / H5 = 7  => 13 pairs (_) / H8 = 7  => 14 pairs (_)
I5,I7: 7.. / I5 = 7  => 14 pairs (_) / I7 = 7  => 13 pairs (_)
H1,I3: 8.. / H1 = 8  =>  0 pairs (X) / I3 = 8  =>  0 pairs (_)
B5,C5: 8.. / B5 = 8  => 13 pairs (_) / C5 = 8  => 11 pairs (_)
E4,F6: 8.. / E4 = 8  =>  0 pairs (*) / F6 = 8  =>  0 pairs (X)
G8,G9: 8.. / G8 = 8  => 11 pairs (_) / G9 = 8  => 10 pairs (_)
D9,G9: 8.. / D9 = 8  => 11 pairs (_) / G9 = 8  => 10 pairs (_)
C2,C5: 8.. / C2 = 8  => 13 pairs (_) / C5 = 8  => 11 pairs (_)
H1,I3: 9.. / H1 = 9  =>  0 pairs (*) / I3 = 9  =>  0 pairs (X)
* DURATION: 0:00:51.354533  START: 15:25:13.952546  END: 15:26:05.307079 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C7,C9,D7,E4,F5,G8,G9,H1,H8,I3,I9)
* 134.6.5.2...1.27432.73.461..736.12.....23.1...2147.3..8...4392.3.2.1...67...26.3.
* PAIR H1: 8,9 ROW 1
D1: 8,9,7                                # reduction candidate for 8,9
D1: 8,9                                  # 13 pairs
F1: 8,9,7                                # reduction candidate for 8,9
F1: 8,9                                  # 15 pairs
* PAIR H1: 8,9 COL H
H4: 8,9,5                                # reduction candidate for 8,9
H4: 8,9                                  # 15 pairs
H6: 8,9,5,6                              # reduction candidate for 8,9
H6: 8,9 => SOLVED
* 134867592568192743297354618973681254485239167621475389816743925352918476749526831
H6: 5,6                                  # 12 pairs
* PAIR I3: 8,9 ROW 3
B3: 8,9,5                                # reduction candidate for 8,9
B3: 8,9                                  # 13 pairs
E3: 8,9,5                                # reduction candidate for 8,9
E3: 8,9                                  # 15 pairs
* PAIR I3: 8,9 COL I
I4: 8,9,4,5                              # reduction candidate for 8,9
I4: 8,9 => CTR
* 134.6.5.2...1.27432.73.461.4736.125....23.1.4.2147.3..8...439273.2.1...67...26.3.
I4: 4,5                                  # 12 pairs
I6: 8,9,5                                # reduction candidate for 8,9
I6: 8,9                                  # 13 pairs
* PAIR E4: 8,9 BLK 5
F6: 8,9,5                                # reduction candidate for 8,9
F6: 5 => SOLVED
* 134867592568192743297354618973681254485239167621475389816743925352918476749526831
F6: 8,9                                  # 12 pairs
* PAIR E4: 8,9 ROW 4
H4: 8,9,5                                # reduction candidate for 8,9
H4: 8,9                                  # 15 pairs
I4: 8,9,4,5                              # reduction candidate for 8,9
I4: 8,9 => CTR
* 134.6.5.2...1.27432.73.461.4736.125....23.1.4.2147.3..8...439273.2.1...67...26.3.
I4: 4,5                                  # 12 pairs
* PAIR E4: 8,9 COL E
E2: 8,9,5                                # reduction candidate for 8,9
E2: 8,9                                  # 13 pairs
E3: 8,9,5                                # reduction candidate for 8,9
E3: 8,9                                  # 15 pairs
* PAIR F5: 5,9 BLK 5
F6: 5,9,8                                # reduction candidate for 5,9
F6: 5,9 => SOLVED
* 134867592568192743297354618973681254485239167621475389816743925352918476749526831
F6: 8 => CTR
* 134.6.582...1.27432.73.4619.7369125....2351...214783..8...4392.3.2.1...67...26.3.
* PAIR F5: 5,9 ROW 5
A5: 5,9,4,6                              # reduction candidate for 5,9
A5: 5,9                                  # 14 pairs
B5: 5,9,6,8                              # reduction candidate for 5,9
B5: 5,9                                  # 16 pairs
C5: 5,9,6,8                              # reduction candidate for 5,9
C5: 5,9                                  # 18 pairs
H5: 5,9,6,7                              # reduction candidate for 5,9
H5: 5,9                                  # 18 pairs
I5: 5,9,4,7                              # reduction candidate for 5,9
I5: 5,9                                  # 14 pairs
* PAIR C7: 5,6 BLK 7
B7: 5,6,1                                # reduction candidate for 5,6
B7: 5,6 => CTR
* 134967582...1.27432.73.4619.7369125....23.1.7.2147.3..8..743921342519876719826435
B7: 1                                    # 10 pairs
* PAIR C7: 5,6 COL C
C2: 5,6,8,9                              # reduction candidate for 5,6
C2: 5,6                                  # 13 pairs
C5: 5,6,8,9                              # reduction candidate for 5,6
C5: 5,6                                  # 16 pairs
* PAIR C9: 5,9 BLK 7
B8: 5,9,4                                # reduction candidate for 5,9
B8: 5,9                                  # 10 pairs
B9: 5,9,1,4                              # reduction candidate for 5,9
B9: 5,9                                  # 11 pairs
* PAIR C9: 5,9 ROW 9
D9: 5,9,8                                # reduction candidate for 5,9
D9: 8                                    # 11 pairs
D9: 5,9                                  # 10 pairs
* PAIR C9: 5,9 COL C
C2: 5,9,6,8                              # reduction candidate for 5,9
C2: 5,9                                  # 12 pairs
C5: 5,9,6,8                              # reduction candidate for 5,9
C5: 5,9                                  # 18 pairs
* PAIR D7: 5,7 BLK 8
D8: 5,7,8,9                              # reduction candidate for 5,7
D8: 5,7                                  # 16 pairs
D8: 8,9                                  # 12 pairs
* PAIR D7: 5,7 ROW 7
I7: 5,7,1                                # reduction candidate for 5,7
I7: 1 => CTR
* 134967582...1.27432.73.4619.736.12.44..23.1.7.2147.3..8..743921342519876719826435
I7: 5,7                                  # 10 pairs
* PAIR H8: 5,7 BLK 9
I7: 5,7,1                                # reduction candidate for 5,7
I7: 1 => CTR
* 134967582...1.27432.73.4619.736.12.44..23.1.7.2147.3..8..743921342519876719826435
I7: 5,7                                  # 10 pairs
* PAIR H8: 5,7 ROW 8
D8: 5,7,8,9                              # reduction candidate for 5,7
D8: 5,7                                  # 16 pairs
D8: 8,9                                  # 12 pairs
* PAIR H8: 5,7 COL H
H5: 5,7,6,9                              # reduction candidate for 5,7
H5: 5,7                                  # 16 pairs
H5: 6,9                                  # 15 pairs
* PAIR I9: 1,5 BLK 9
I7: 1,5,7                                # reduction candidate for 1,5
I7: 1,5                                  # 14 pairs
I7: 7                                    # 13 pairs
* PAIR I9: 1,5 ROW 9
B9: 1,5,4,9                              # reduction candidate for 1,5
B9: 4,9                                  # 11 pairs
B9: 1,5                                  # 11 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-368-base-pr-000.dot
* REASONING
* PRF # H6: 8,9 => SOL
* DIS # I4: 8,9 => CTR => I4: 4,5
* PRF # F6: 5 => SOL
* DIS # I4: 8,9 => CTR => I4: 4,5
* PRF # F6: 5,9 => SOL
* DIS # F6: 8 => CTR => F6: 5,9
* DIS # B7: 5,6 => CTR => B7: 1
* DIS # I7: 1 => CTR => I7: 5,7
* DIS # I7: 1 => CTR => I7: 5,7
* CNT   9 HDP CHAINS /  48 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C7,C9,D7,E4,F5,G8,G9,H1,H8,I3,I9)
* 134.6.5.2...1.27432.73.461..736.12.....23.1...2147.3..8...4392.3.2.1...67...26.3.
* PAIR H1: 8,9 ROW 1
D1: 8,9,7                                # reduction candidate for 8,9
D1: 8,9                                  # 13 pairs
F1: 8,9,7                                # reduction candidate for 8,9
F1: 8,9                                  # 15 pairs
* PAIR H1: 8,9 COL H
H4: 8,9,5                                # reduction candidate for 8,9
H4: 8,9                                  # 15 pairs
H6: 8,9,5,6                              # reduction candidate for 8,9
H6: 8,9 => SOLVED
* 134867592568192743297354618973681254485239167621475389816743925352918476749526831
* DURATION: 0:00:04.668630  START: 15:26:47.655668  END: 15:26:52.324298 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-368-base-pr-001.dot
* REASONING
* PRF # H6: 8,9 => SOL
* STA H6: 8,9
* CNT   1 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 368

solution: 134867592568192743297354618973681254485239167621475389816743925352918476749526831
info: 5147     FNBTWX   S8.f     26045

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

Solution

position: 134867592568192743297354618973681254485239167621475389816743925352918476749526831 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 # D1: 8,9 => UNS
* INC # F1: 8,9 => UNS
* INC # H4: 8,9 => UNS
* PRF # H6: 8,9 => SOL
* INC # H6: 5,6 => UNS
* INC # B3: 8,9 => UNS
* INC # E3: 8,9 => UNS
* DIS # I4: 8,9 => CTR => I4: 4,5
* INC # I4: 4,5 => UNS
* INC # I6: 8,9 => UNS
* INC # F6: 8,9 => UNS
* PRF # F6: 5 => SOL
* INC # H4: 8,9 => UNS
* DIS # I4: 8,9 => CTR => I4: 4,5
* INC # I4: 4,5 => UNS
* INC # E2: 8,9 => UNS
* INC # E3: 8,9 => UNS
* PRF # F6: 5,9 => SOL
* DIS # F6: 8 => CTR => F6: 5,9
* INC # A5: 5,9 => UNS
* INC # B5: 5,9 => UNS
* INC # C5: 5,9 => UNS
* INC # H5: 5,9 => UNS
* INC # I5: 5,9 => UNS
* DIS # B7: 5,6 => CTR => B7: 1
* INC # B7: 1 => UNS
* INC # C2: 5,6 => UNS
* INC # C5: 5,6 => UNS
* INC # B8: 5,9 => UNS
* INC # B9: 5,9 => UNS
* INC # D9: 5,9 => UNS
* INC # D9: 8 => UNS
* INC # C2: 5,9 => UNS
* INC # C5: 5,9 => UNS
* INC # D8: 5,7 => UNS
* INC # D8: 8,9 => UNS
* INC # I7: 5,7 => UNS
* DIS # I7: 1 => CTR => I7: 5,7
* INC # I7: 5,7 => UNS
* DIS # I7: 1 => CTR => I7: 5,7
* INC # D8: 5,7 => UNS
* INC # D8: 8,9 => UNS
* INC # H5: 5,7 => UNS
* INC # H5: 6,9 => UNS
* INC # I7: 1,5 => UNS
* INC # I7: 7 => UNS
* INC # B9: 1,5 => UNS
* INC # B9: 4,9 => UNS
* CNT  48 HDP CHAINS /  48 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D1: 8,9 => UNS
* INC # F1: 8,9 => UNS
* INC # H4: 8,9 => UNS
* PRF # H6: 8,9 => SOL
* STA H6: 8,9
* CNT   4 HDP CHAINS /   4 HYP OPENED