Analysis of xx-top500-412-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..71..........89..6...............41...2...7.3........58....3.....72....1...4.... initial

Autosolve

position: ..71..4......789..6.....7..7......41...2...733....7...584...3279..725184172843... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I1: 5,6 => CTR => I1: 2,8
* DIS # F5: 6,9 => CTR => F5: 1,4
* DIS # B4: 6,9 => CTR => B4: 2,5
* DIS # F7: 6,9 => CTR => F7: 1
* DIS # F7: 6,9 => CTR => F7: 1
* DIS # G4: 5,6 => CTR => G4: 2,8
* DIS # G6: 5,6 => CTR => G6: 2,8
* CNT   7 HDP CHAINS /  25 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 # I1: 5,6 => CTR => I1: 2,8
* DIS I1: 2,8 # D4: 6,9 => CTR => D4: 3,5
* DIS I1: 2,8 + D4: 3,5 # B2: 3,5 => CTR => B2: 1
* PRF I1: 2,8 + D4: 3,5 + B2: 1 # B1: 9 => SOL
* STA I1: 2,8 + D4: 3,5 + B2: 1 + B1: 9
* CNT   4 HDP CHAINS /   7 HYP OPENED

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

Details

Positions

..71..........89..6...............41...2...7.3........58....3.....72....1...4.... initial
..71..4......789..6.....7..7......41...2...733....7...584...3279..725184172843... autosolve
297156438415378962638492715726539841859214673341687259584961327963725184172843596 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
A1: 2,8
A2: 2,4
A5: 4,8
F4: 6,9
B8: 3,6
C8: 3,6
D7: 6,9
G9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H2,H3: 1.. / H2 = 1  => 10 pairs (_) / H3 = 1  =>  8 pairs (_)
E7,F7: 1.. / E7 = 1  =>  0 pairs (X) / F7 = 1  =>  9 pairs (_)
F5,F7: 1.. / F5 = 1  =>  0 pairs (X) / F7 = 1  =>  9 pairs (_)
A1,A2: 2.. / A1 = 2  => 19 pairs (_) / A2 = 2  =>  0 pairs (X)
F1,F3: 2.. / F1 = 2  =>  0 pairs (X) / F3 = 2  => 19 pairs (_)
B4,B6: 2.. / B4 = 2  =>  8 pairs (_) / B6 = 2  =>  0 pairs (X)
G4,G6: 2.. / G4 = 2  =>  0 pairs (X) / G6 = 2  =>  8 pairs (_)
A2,I2: 2.. / A2 = 2  =>  0 pairs (X) / I2 = 2  => 19 pairs (_)
F3,I3: 2.. / F3 = 2  => 19 pairs (_) / I3 = 2  =>  0 pairs (X)
B4,G4: 2.. / B4 = 2  =>  8 pairs (_) / G4 = 2  =>  0 pairs (X)
B6,G6: 2.. / B6 = 2  =>  0 pairs (X) / G6 = 2  =>  8 pairs (_)
D4,E4: 3.. / D4 = 3  =>  8 pairs (_) / E4 = 3  =>  9 pairs (_)
B8,C8: 3.. / B8 = 3  =>  7 pairs (_) / C8 = 3  =>  7 pairs (_)
F5,D6: 4.. / F5 = 4  => 19 pairs (_) / D6 = 4  =>  0 pairs (X)
B6,D6: 4.. / B6 = 4  => 19 pairs (_) / D6 = 4  =>  0 pairs (X)
A2,A5: 4.. / A2 = 4  => 19 pairs (_) / A5 = 4  =>  0 pairs (X)
F3,F5: 4.. / F3 = 4  =>  0 pairs (X) / F5 = 4  => 19 pairs (_)
B8,C8: 6.. / B8 = 6  =>  7 pairs (_) / C8 = 6  =>  7 pairs (_)
A1,C3: 8.. / A1 = 8  =>  0 pairs (X) / C3 = 8  => 19 pairs (_)
I1,I3: 8.. / I1 = 8  => 19 pairs (_) / I3 = 8  =>  0 pairs (X)
A1,I1: 8.. / A1 = 8  =>  0 pairs (X) / I1 = 8  => 19 pairs (_)
C3,I3: 8.. / C3 = 8  => 19 pairs (_) / I3 = 8  =>  0 pairs (X)
A1,A5: 8.. / A1 = 8  =>  0 pairs (X) / A5 = 8  => 19 pairs (_)
H6,I6: 9.. / H6 = 9  => 10 pairs (_) / I6 = 9  => 10 pairs (_)
H9,I9: 9.. / H9 = 9  => 10 pairs (_) / I9 = 9  => 10 pairs (_)
H6,H9: 9.. / H6 = 9  => 10 pairs (_) / H9 = 9  => 10 pairs (_)
I6,I9: 9.. / I6 = 9  => 10 pairs (_) / I9 = 9  => 10 pairs (_)
* DURATION: 0:00:37.839908  START: 16:53:01.089047  END: 16:53:38.928955 2017-05-04
* CP COUNT: (27)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,A5,B8,C8,D7,F4,G9)
* ..71..4......789..6.....7..7......41...2...733....7...584...3279..725184172843...
* PAIR A1: 2,8 ROW 1
I1: 2,8,5,6                              # reduction candidate for 2,8
I1: 5,6 => CTR
* 8.71.24..2...789..6.....7..7......41...2...733....7...584...3279..725184172843...
I1: 2,8                                  # 19 pairs
* PAIR F4: 6,9 BLK 5
D4: 6,9,3,5                              # reduction candidate for 6,9
D4: 6,9                                  # 15 pairs
E4: 6,9,3,5,8                            # reduction candidate for 6,9
E4: 6,9                                  # 13 pairs
E5: 6,9,1,5,8                            # reduction candidate for 6,9
E5: 6,9                                  # 12 pairs
F5: 6,9,1,4                              # reduction candidate for 6,9
F5: 6,9 => CTR
* ..71.24.8....789..6....47.27......41...2...733..4.7...584..13279..725184172843...
F5: 1,4                                  #  9 pairs
* PAIR F4: 6,9 ROW 4
B4: 6,9,2,5                              # reduction candidate for 6,9
B4: 6,9 => CTR
* ..71.24.8....789..6....47.27.....241...2...7332.4.7...584...3279..725184172843...
B4: 2,5                                  #  9 pairs
C4: 6,9,5,8                              # reduction candidate for 6,9
C4: 6,9                                  # 11 pairs
* PAIR F4: 6,9 COL F
F1: 6,9,2                                # reduction candidate for 6,9
F1: 6,9                                  # 19 pairs
F7: 6,9,1                                # reduction candidate for 6,9
F7: 6,9 => CTR
* ..71.24.8....789..6....47.27......41...2.1.733..4.7...584.1.3279..725184172843...
F7: 1                                    #  9 pairs
* PAIR D7: 6,9 BLK 8
E7: 6,9,1                                # reduction candidate for 6,9
E7: 6,9                                  #  9 pairs
F7: 6,9,1                                # reduction candidate for 6,9
F7: 6,9 => CTR
* ..71.24.8....789..6....47.27......41...2.1.733..4.7...584.1.3279..725184172843...
F7: 1                                    #  9 pairs
* PAIR D7: 6,9 COL D
D4: 6,9,3,5                              # reduction candidate for 6,9
D4: 6,9                                  # 15 pairs
D4: 3,5                                  #  9 pairs
* PAIR G9: 5,6 BLK 9
H9: 5,6,9                                # reduction candidate for 5,6
H9: 5,6                                  # 10 pairs
I9: 5,6,9                                # reduction candidate for 5,6
I9: 5,6                                  # 10 pairs
* PAIR G9: 5,6 COL G
G4: 5,6,2,8                              # reduction candidate for 5,6
G4: 5,6 => CTR
* 8.71..4..2...789..6.....7.872.....414..2..8733..4.72..584...3279..725184172843...
G4: 2,8                                  #  9 pairs
G5: 5,6,8                                # reduction candidate for 5,6
G5: 5,6                                  # 11 pairs
G6: 5,6,2,8                              # reduction candidate for 5,6
G6: 5,6 => CTR
* 8.71..4..24..789..6....47..7.....241...2..87332.4.7...584...3279..725184172843...
G6: 2,8                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-412-base-pr-000.dot
* REASONING
* DIS # I1: 5,6 => CTR => I1: 2,8
* DIS # F5: 6,9 => CTR => F5: 1,4
* DIS # B4: 6,9 => CTR => B4: 2,5
* DIS # F7: 6,9 => CTR => F7: 1
* DIS # F7: 6,9 => CTR => F7: 1
* DIS # G4: 5,6 => CTR => G4: 2,8
* DIS # G6: 5,6 => CTR => G6: 2,8
* CNT   7 HDP CHAINS /  25 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A2,A5,B8,C8,D7,F4,G9)
* ..71..4......789..6.....7..7......41...2...733....7...584...3279..725184172843...
* PAIR A1: 2,8 ROW 1
I1: 2,8,5,6                              # reduction candidate for 2,8
I1: 5,6 => CTR
* 8.71.24..2...789..6.....7..7......41...2...733....7...584...3279..725184172843...
* PAIR RESTART
* PAIR F4: 6,9 BLK 5
D4: 6,9,3,5                              # reduction candidate for 6,9
D4: 6,9 => CTR
* 2.71..4.84..3789626.849271572..398418.9214.733415872965849613279.3725184172843659
* RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (B5,B8,C2,C4,C8,D4,D6,E3,F1,F4,G5,G9,H1,H3,H6,H9,I6,I9)
* 2.71..4.84...789.26.84.27.572....8418.9214.73341.872..5849613279..725184172843...
* PAIR C2: 3,5 BLK 1
B1: 3,5,9                                # reduction candidate for 3,5
B1: 3,5                                  # 20 pairs
B2: 3,5,1                                # reduction candidate for 3,5
B2: 3,5 => CTR
* 2.71..4.84...7891261849273572...98418.9214.733416872595849613279..725184172843596
* RESTART
* PAIR C2: 3,5 BLK 1
B1: 3,5,9                                # reduction candidate for 3,5
B1: 9 => SOLVED
* 297156438415378962638492715726539841859214673341687259584961327963725184172843596
* DURATION: 0:00:10.010321  START: 16:53:57.854202  END: 16:54:07.864523 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-412-base-pr-001.dot
* REASONING
* DIS # I1: 5,6 => CTR => I1: 2,8
* DIS I1: 2,8 # D4: 6,9 => CTR => D4: 3,5
* DIS I1: 2,8 + D4: 3,5 # B2: 3,5 => CTR => B2: 1
* PRF I1: 2,8 + D4: 3,5 + B2: 1 # B1: 9 => SOL
* STA I1: 2,8 + D4: 3,5 + B2: 1 + B1: 9
* CNT   4 HDP CHAINS /   7 HYP OPENED

Header Info

Top 500 Minimum 17 412

solution: 297156438415378962638492715726539841859214673341687259584961327963725184172843596
info: 95023    FNBXYK   S8.f     14367

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

Solution

position: 297156438415378962638492715726539841859214673341687259584961327963725184172843596 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 # I1: 2,8 => UNS
* DIS # I1: 5,6 => CTR => I1: 2,8
* INC # D4: 6,9 => UNS
* INC # E4: 6,9 => UNS
* INC # E5: 6,9 => UNS
* DIS # F5: 6,9 => CTR => F5: 1,4
* INC # F5: 1,4 => UNS
* DIS # B4: 6,9 => CTR => B4: 2,5
* INC # B4: 2,5 => UNS
* INC # C4: 6,9 => UNS
* INC # F1: 6,9 => UNS
* DIS # F7: 6,9 => CTR => F7: 1
* INC # F7: 1 => UNS
* INC # E7: 6,9 => UNS
* DIS # F7: 6,9 => CTR => F7: 1
* INC # F7: 1 => UNS
* INC # D4: 6,9 => UNS
* INC # D4: 3,5 => UNS
* INC # H9: 5,6 => UNS
* INC # I9: 5,6 => UNS
* DIS # G4: 5,6 => CTR => G4: 2,8
* INC # G4: 2,8 => UNS
* INC # G5: 5,6 => UNS
* DIS # G6: 5,6 => CTR => G6: 2,8
* INC # G6: 2,8 => UNS
* CNT  25 HDP CHAINS /  25 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # I1: 2,8 => UNS
* DIS # I1: 5,6 => CTR => I1: 2,8
* DIS I1: 2,8 # D4: 6,9 => CTR => D4: 3,5
* INC I1: 2,8 + D4: 3,5 # B1: 3,5 => UNS
* DIS I1: 2,8 + D4: 3,5 # B2: 3,5 => CTR => B2: 1
* INC I1: 2,8 + D4: 3,5 + B2: 1 # B1: 3,5 => UNS
* PRF I1: 2,8 + D4: 3,5 + B2: 1 # B1: 9 => SOL
* STA I1: 2,8 + D4: 3,5 + B2: 1 + B1: 9
* CNT   7 HDP CHAINS /   7 HYP OPENED