Analysis of xx-top500-223-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....2..5.3.....1.......6....6..5..2.1..4..3..............1.8....2.....7....3..4.. initial

Autosolve

position: ....2.65.3765841922.5..6....6.85..2.15246.38....2..5.6...1.82...2.6.5.7....3.24.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # F6: 1,3 => SOL
* DIS # I1: 7,8 => CTR => I1: 3,4
* DIS # I3: 3,4 => CTR => I3: 7,8
* PRF # F4: 7,9 => SOL
* PRF # F6: 1,3 => SOL
* PRF # F4: 7,9 => SOL
* DIS # A8: 8 => CTR => A8: 4,9
* DIS # I9: 8 => CTR => I9: 5,9
* DIS # I9: 8,9 => CTR => I9: 5
* PRF # I9: 5 => SOL
* CNT  10 HDP CHAINS /  32 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 # F6: 1,3 => SOL
* STA F6: 1,3
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

....2..5.3.....1.......6....6..5..2.1..4..3..............1.8....2.....7....3..4.. initial
....2.65.3765841922.5..6....6.85..2.15246.38....2..5.6...1.82...2.6.5.7....3.24.. autosolve
819723654376584192245916738463857921152469387798231546534178269921645873687392415 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (22)
D1: 7,9
F1: 1,3
D3: 7,9
E3: 1,3
G3: 7,8
H3: 3,4
F5: 7,9
E6: 1,3
G4: 7,9
I4: 1,4
I5: 7,9
H6: 1,4
A7: 5,6
C8: 1,3
A9: 5,6
E8: 4,9
E9: 7,9
H7: 3,6
I7: 5,9
G8: 8,9
I8: 1,3
H9: 1,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F1,E3: 1.. / F1 = 1  =>  0 pairs (X) / E3 = 1  =>  0 pairs (_)
I4,H6: 1.. / I4 = 1  =>  0 pairs (*) / H6 = 1  =>  0 pairs (X)
I8,H9: 1.. / I8 = 1  =>  0 pairs (X) / H9 = 1  =>  0 pairs (_)
B3,E3: 1.. / B3 = 1  =>  0 pairs (X) / E3 = 1  =>  0 pairs (_)
F4,I4: 1.. / F4 = 1  =>  0 pairs (X) / I4 = 1  =>  0 pairs (_)
C8,I8: 1.. / C8 = 1  =>  0 pairs (*) / I8 = 1  =>  0 pairs (X)
E3,E6: 1.. / E3 = 1  =>  0 pairs (*) / E6 = 1  =>  0 pairs (X)
H6,H9: 1.. / H6 = 1  =>  0 pairs (X) / H9 = 1  =>  0 pairs (_)
I4,I8: 1.. / I4 = 1  =>  0 pairs (*) / I8 = 1  =>  0 pairs (X)
F1,E3: 3.. / F1 = 3  =>  0 pairs (*) / E3 = 3  =>  0 pairs (X)
H7,I8: 3.. / H7 = 3  =>  0 pairs (X) / I8 = 3  =>  0 pairs (_)
F1,I1: 3.. / F1 = 3  =>  0 pairs (*) / I1 = 3  =>  0 pairs (X)
C4,F4: 3.. / C4 = 3  =>  0 pairs (*) / F4 = 3  =>  0 pairs (X)
C8,I8: 3.. / C8 = 3  =>  0 pairs (X) / I8 = 3  =>  0 pairs (_)
B6,B7: 3.. / B6 = 3  =>  0 pairs (X) / B7 = 3  =>  0 pairs (_)
E3,E6: 3.. / E3 = 3  =>  0 pairs (X) / E6 = 3  =>  0 pairs (_)
H3,H7: 3.. / H3 = 3  =>  0 pairs (*) / H7 = 3  =>  0 pairs (X)
I4,H6: 4.. / I4 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
E7,E8: 4.. / E7 = 4  => 19 pairs (_) / E8 = 4  => 23 pairs (_)
A8,E8: 4.. / A8 = 4  => 19 pairs (_) / E8 = 4  => 23 pairs (_)
H3,H6: 4.. / H3 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
A7,A9: 5.. / A7 = 5  =>  0 pairs (*) / A9 = 5  =>  0 pairs (X)
I7,I9: 5.. / I7 = 5  =>  0 pairs (X) / I9 = 5  =>  0 pairs (_)
A7,I7: 5.. / A7 = 5  =>  0 pairs (*) / I7 = 5  =>  0 pairs (X)
A9,I9: 5.. / A9 = 5  =>  0 pairs (X) / I9 = 5  =>  0 pairs (_)
A7,A9: 6.. / A7 = 6  =>  0 pairs (X) / A9 = 6  =>  0 pairs (_)
H7,H9: 6.. / H7 = 6  =>  0 pairs (*) / H9 = 6  =>  0 pairs (X)
A7,H7: 6.. / A7 = 6  =>  0 pairs (X) / H7 = 6  =>  0 pairs (_)
A9,H9: 6.. / A9 = 6  =>  0 pairs (*) / H9 = 6  =>  0 pairs (X)
D1,D3: 7.. / D1 = 7  => 20 pairs (_) / D3 = 7  =>  0 pairs (X)
A4,A6: 7.. / A4 = 7  => 19 pairs (_) / A6 = 7  => 23 pairs (_)
G4,I5: 7.. / G4 = 7  =>  0 pairs (X) / I5 = 7  => 19 pairs (_)
C7,C9: 7.. / C7 = 7  => 22 pairs (_) / C9 = 7  => 23 pairs (_)
E7,E9: 7.. / E7 = 7  => 23 pairs (_) / E9 = 7  => 22 pairs (_)
D1,I1: 7.. / D1 = 7  => 20 pairs (_) / I1 = 7  =>  0 pairs (X)
F5,I5: 7.. / F5 = 7  =>  0 pairs (X) / I5 = 7  => 19 pairs (_)
A6,F6: 7.. / A6 = 7  => 23 pairs (_) / F6 = 7  => 19 pairs (_)
C7,E7: 7.. / C7 = 7  => 22 pairs (_) / E7 = 7  => 23 pairs (_)
C9,E9: 7.. / C9 = 7  => 23 pairs (_) / E9 = 7  => 22 pairs (_)
G3,G4: 7.. / G3 = 7  => 19 pairs (_) / G4 = 7  =>  0 pairs (X)
G8,I9: 8.. / G8 = 8  => 19 pairs (_) / I9 = 8  =>  0 pairs (X)
A8,G8: 8.. / A8 = 8  =>  0 pairs (X) / G8 = 8  => 19 pairs (_)
G3,G8: 8.. / G3 = 8  =>  0 pairs (X) / G8 = 8  => 19 pairs (_)
D1,D3: 9.. / D1 = 9  =>  0 pairs (X) / D3 = 9  => 20 pairs (_)
G4,I5: 9.. / G4 = 9  => 19 pairs (_) / I5 = 9  =>  0 pairs (X)
B3,D3: 9.. / B3 = 9  =>  0 pairs (X) / D3 = 9  => 20 pairs (_)
F5,I5: 9.. / F5 = 9  => 19 pairs (_) / I5 = 9  =>  0 pairs (X)
G4,G8: 9.. / G4 = 9  => 19 pairs (_) / G8 = 9  =>  0 pairs (X)
* DURATION: 0:01:37.941830  START: 10:25:48.421634  END: 10:27:26.363464 2017-05-04
* CP COUNT: (48)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,A9,C8,D1,D3,E3,E6,E8,E9,F1,F5,G3,G4,G8,H3,H6,H7,H9,I4,I5,I7,I8)
* ....2.65.3765841922.5..6....6.85..2.15246.38....2..5.6...1.82...2.6.5.7....3.24..
* PAIR F1: 1,3 COL F
F4: 1,3,7,9                              # reduction candidate for 1,3
F4: 1,3                                  # 24 pairs
F6: 1,3,7,9                              # reduction candidate for 1,3
F6: 1,3 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
F6: 7,9                                  # 24 pairs
* PAIR G3: 7,8 BLK 3
I1: 7,8,3,4                              # reduction candidate for 7,8
I1: 7,8 => CTR
* .1..2365.3765841922.5.16.3446385..2115246.38.7..231546534178269.216458736.7392415
I1: 3,4                                  # 23 pairs
I3: 7,8,3,4                              # reduction candidate for 7,8
I3: 7,8                                  # 23 pairs
* PAIR H3: 3,4 BLK 3
I1: 3,4,7,8                              # reduction candidate for 3,4
I1: 3,4                                  # 23 pairs
I3: 3,4,7,8                              # reduction candidate for 3,4
I3: 3,4 => CTR
* .1..2365837658419228591673446385792115246938779.23.5.6.3.1.826..216.5.736..3.2415
I3: 7,8                                  # 23 pairs
* PAIR F5: 7,9 BLK 5
F4: 7,9,1,3                              # reduction candidate for 7,9
F4: 7,9 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
F4: 1,3                                  # 24 pairs
F6: 7,9,1,3                              # reduction candidate for 7,9
F6: 7,9                                  # 24 pairs
* PAIR E6: 1,3 BLK 5
F4: 1,3,7,9                              # reduction candidate for 1,3
F4: 1,3                                  # 24 pairs
F6: 1,3,7,9                              # reduction candidate for 1,3
F6: 1,3 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
F6: 7,9                                  # 24 pairs
* PAIR G4: 7,9 ROW 4
A4: 7,9,4                                # reduction candidate for 7,9
A4: 7,9                                  # 26 pairs
F4: 7,9,1,3                              # reduction candidate for 7,9
F4: 7,9 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
F4: 1,3                                  # 24 pairs
* PAIR E8: 4,9 BLK 8
E7: 4,9,7                                # reduction candidate for 4,9
E7: 7                                    # 23 pairs
E7: 4,9                                  # 22 pairs
* PAIR E8: 4,9 ROW 8
A8: 4,9,8                                # reduction candidate for 4,9
A8: 8 => CTR
* ....2.65.3765841922.5..68...6.85.72.1524673897..2..5166..1.82358236459715..3.2468
A8: 4,9                                  # 19 pairs
* PAIR E9: 7,9 BLK 8
E7: 7,9,4                                # reduction candidate for 7,9
E7: 7,9                                  # 23 pairs
E7: 4                                    # 19 pairs
* PAIR E9: 7,9 ROW 9
C9: 7,9,1,8                              # reduction candidate for 7,9
C9: 7,9                                  # 25 pairs
C9: 1,8                                  # 23 pairs
* PAIR I7: 5,9 BLK 9
I9: 5,9,8                                # reduction candidate for 5,9
I9: 8 => CTR
* ....2.65.3765841922.5..68...6.85.72.1524673897..2..5166..1.82358236459715..3.2468
I9: 5,9                                  # 19 pairs
* PAIR G8: 8,9 BLK 9
I9: 8,9,5                                # reduction candidate for 8,9
I9: 8,9 => CTR
* ....2.65.3765841922.5..6....6.85..2.15246.38....2..5166..1.8235.236.5.715..3.246.
I9: 5 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
* PAIR G8: 8,9 ROW 8
A8: 8,9,4                                # reduction candidate for 8,9
A8: 8,9                                  # 23 pairs
A8: 4                                    # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-223-base-pr-000.dot
* REASONING
* PRF # F6: 1,3 => SOL
* DIS # I1: 7,8 => CTR => I1: 3,4
* DIS # I3: 3,4 => CTR => I3: 7,8
* PRF # F4: 7,9 => SOL
* PRF # F6: 1,3 => SOL
* PRF # F4: 7,9 => SOL
* DIS # A8: 8 => CTR => A8: 4,9
* DIS # I9: 8 => CTR => I9: 5,9
* DIS # I9: 8,9 => CTR => I9: 5
* PRF # I9: 5 => SOL
* CNT  10 HDP CHAINS /  32 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,A9,C8,D1,D3,E3,E6,E8,E9,F1,F5,G3,G4,G8,H3,H6,H7,H9,I4,I5,I7,I8)
* ....2.65.3765841922.5..6....6.85..2.15246.38....2..5.6...1.82...2.6.5.7....3.24..
* PAIR F1: 1,3 COL F
F4: 1,3,7,9                              # reduction candidate for 1,3
F4: 1,3                                  # 24 pairs
F6: 1,3,7,9                              # reduction candidate for 1,3
F6: 1,3 => SOLVED
* 819723654376584192245916738463857921152469387798231546534178269921645873687392415
* DURATION: 0:00:03.655340  START: 10:28:04.183071  END: 10:28:07.838411 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-223-base-pr-001.dot
* REASONING
* PRF # F6: 1,3 => SOL
* STA F6: 1,3
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 223

solution: 819723654376584192245916738463857921152469387798231546534178269921645873687392415
info: 1996     FNBTHWY  S8.f     3230

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

Solution

position: 819723654376584192245916738463857921152469387798231546534178269921645873687392415 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 # F4: 1,3 => UNS
* PRF # F6: 1,3 => SOL
* INC # F6: 7,9 => UNS
* DIS # I1: 7,8 => CTR => I1: 3,4
* INC # I1: 3,4 => UNS
* INC # I3: 7,8 => UNS
* INC # I1: 3,4 => UNS
* DIS # I3: 3,4 => CTR => I3: 7,8
* INC # I3: 7,8 => UNS
* PRF # F4: 7,9 => SOL
* INC # F4: 1,3 => UNS
* INC # F6: 7,9 => UNS
* INC # F4: 1,3 => UNS
* PRF # F6: 1,3 => SOL
* INC # F6: 7,9 => UNS
* INC # A4: 7,9 => UNS
* PRF # F4: 7,9 => SOL
* INC # F4: 1,3 => UNS
* INC # E7: 4,9 => UNS
* INC # E7: 7 => UNS
* INC # A8: 4,9 => UNS
* DIS # A8: 8 => CTR => A8: 4,9
* INC # E7: 7,9 => UNS
* INC # E7: 4 => UNS
* INC # C9: 7,9 => UNS
* INC # C9: 1,8 => UNS
* INC # I9: 5,9 => UNS
* DIS # I9: 8 => CTR => I9: 5,9
* DIS # I9: 8,9 => CTR => I9: 5
* PRF # I9: 5 => SOL
* INC # A8: 8,9 => UNS
* INC # A8: 4 => UNS
* CNT  32 HDP CHAINS /  32 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # F4: 1,3 => UNS
* PRF # F6: 1,3 => SOL
* STA F6: 1,3
* CNT   2 HDP CHAINS /   2 HYP OPENED