Analysis of zz-www.sudokuwiki.org-0050-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=50

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=50

position: ...7...86.28.1.7.......3...9.5.....3.7..4..5.2.....4.7...6.......4...51.53...2... initial

Autosolve

position: ...7...86.28.1.7.......3...945.....3.7..4..5.2.....4.7..265......4...51253...2... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # G1: 2,9 => SOL
* DIS # G4: 2,6 => CTR => G4: 1,8
* CNT   2 HDP CHAINS /  15 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 # G1: 2,9 => SOL
* STA G1: 2,9
* CNT   1 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

...7...86.28.1.7.......3...9.5.....3.7..4..5.2.....4.7...6.......4...51.53...2... initial
...7...86.28.1.7.......3...945.....3.7..4..5.2.....4.7..265......4...51253...2... autosolve
413725986628419735759863124945271863376948251281536497192654378864397512537182649 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (5)
E1: 2,9
H4: 2,6
H6: 6,9
F7: 1,4
D9: 1,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F7,D9: 1.. / F7 = 1  => 13 pairs (_) / D9 = 1  =>  8 pairs (_)
C9,D9: 1.. / C9 = 1  => 13 pairs (_) / D9 = 1  =>  8 pairs (_)
I3,I5: 1.. / I3 = 1  =>  8 pairs (_) / I5 = 1  =>  8 pairs (_)
E1,G1: 2.. / E1 = 2  =>  4 pairs (_) / G1 = 2  =>  0 pairs (X)
D5,G5: 2.. / D5 = 2  =>  7 pairs (_) / G5 = 2  =>  8 pairs (_)
H3,H4: 2.. / H3 = 2  =>  7 pairs (_) / H4 = 2  =>  7 pairs (_)
G1,H2: 3.. / G1 = 3  => 22 pairs (_) / H2 = 3  =>  6 pairs (_)
D8,E8: 3.. / D8 = 3  =>  6 pairs (_) / E8 = 3  =>  6 pairs (_)
G7,H7: 3.. / G7 = 3  =>  6 pairs (_) / H7 = 3  => 22 pairs (_)
A2,H2: 3.. / A2 = 3  => 22 pairs (_) / H2 = 3  =>  6 pairs (_)
E6,E8: 3.. / E6 = 3  =>  6 pairs (_) / E8 = 3  =>  6 pairs (_)
G1,G7: 3.. / G1 = 3  => 22 pairs (_) / G7 = 3  =>  6 pairs (_)
H2,H7: 3.. / H2 = 3  =>  6 pairs (_) / H7 = 3  => 22 pairs (_)
F7,D9: 4.. / F7 = 4  =>  8 pairs (_) / D9 = 4  => 13 pairs (_)
A1,F1: 4.. / A1 = 4  =>  7 pairs (_) / F1 = 4  => 13 pairs (_)
B1,B3: 5.. / B1 = 5  =>  6 pairs (_) / B3 = 5  =>  8 pairs (_)
I2,I3: 5.. / I2 = 5  =>  6 pairs (_) / I3 = 5  => 10 pairs (_)
D6,F6: 5.. / D6 = 5  =>  6 pairs (_) / F6 = 5  =>  6 pairs (_)
B1,F1: 5.. / B1 = 5  =>  6 pairs (_) / F1 = 5  =>  8 pairs (_)
F2,E3: 6.. / F2 = 6  =>  6 pairs (_) / E3 = 6  => 14 pairs (_)
A8,B8: 6.. / A8 = 6  => 11 pairs (_) / B8 = 6  =>  8 pairs (_)
G9,H9: 6.. / G9 = 6  =>  5 pairs (_) / H9 = 6  => 12 pairs (_)
A2,F2: 6.. / A2 = 6  => 14 pairs (_) / F2 = 6  =>  6 pairs (_)
A3,C3: 7.. / A3 = 7  =>  0 pairs (*) / C3 = 7  =>  0 pairs (X)
E4,F4: 7.. / E4 = 7  =>  8 pairs (_) / F4 = 7  =>  6 pairs (_)
H7,H9: 7.. / H7 = 7  =>  7 pairs (_) / H9 = 7  =>  9 pairs (_)
A7,H7: 7.. / A7 = 7  =>  9 pairs (_) / H7 = 7  =>  7 pairs (_)
C3,C9: 7.. / C3 = 7  =>  7 pairs (_) / C9 = 7  =>  0 pairs (*)
F4,F8: 7.. / F4 = 7  =>  6 pairs (_) / F8 = 7  =>  8 pairs (_)
D3,E3: 8.. / D3 = 8  =>  7 pairs (_) / E3 = 8  => 11 pairs (_)
A5,B6: 8.. / A5 = 8  => 15 pairs (_) / B6 = 8  =>  7 pairs (_)
* DURATION: 0:00:39.688546  START: 04:23:54.692704  END: 04:24:34.381250 2017-05-01
* CP COUNT: (31)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D9,E1,F7,H4,H6)
* ...7...86.28.1.7.......3...945.....3.7..4..5.2.....4.7..265......4...51253...2...
* PAIR E1: 2,9 BLK 2
D3: 2,9,4,5,8                            # reduction candidate for 2,9
D3: 2,9                                  # 16 pairs
E3: 2,9,6,8                              # reduction candidate for 2,9
E3: 2,9                                  # 15 pairs
* PAIR E1: 2,9 ROW 1
G1: 2,9,1,3                              # reduction candidate for 2,9
G1: 2,9 => SOLVED
* 413725986628419735759863124945271863376948251281536497192654378864397512537182649
G1: 1,3                                  #  5 pairs
* PAIR H4: 2,6 BLK 6
G4: 2,6,1,8                              # reduction candidate for 2,6
G4: 2,6 => CTR
* ...7...86.28.1.7.......3...945..1..3.7..4..5.281...4.7..2654.....4...51253.1.2...
G4: 1,8                                  #  6 pairs
G5: 2,6,1,8,9                            # reduction candidate for 2,6
G5: 2,6                                  #  9 pairs
* PAIR H4: 2,6 ROW 4
E4: 2,6,7,8                              # reduction candidate for 2,6
E4: 2,6                                  #  9 pairs
E4: 7,8                                  #  6 pairs
* PAIR H6: 6,9 BLK 6
G5: 6,9,1,2,8                            # reduction candidate for 6,9
G5: 6,9                                  # 12 pairs
G5: 1,2,8                                #  5 pairs
* PAIR H6: 6,9 ROW 6
E6: 6,9,3,8                              # reduction candidate for 6,9
E6: 6,9                                  #  9 pairs
F6: 6,9,1,5,8                            # reduction candidate for 6,9
F6: 6,9                                  # 11 pairs
* PAIR H6: 6,9 COL H
H9: 6,9,4,7                              # reduction candidate for 6,9
H9: 6,9                                  # 10 pairs
H9: 4,7                                  #  6 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0050-base-pr-000.dot
* REASONING
* PRF # G1: 2,9 => SOL
* DIS # G4: 2,6 => CTR => G4: 1,8
* CNT   2 HDP CHAINS /  15 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D9,E1,F7,H4,H6)
* ...7...86.28.1.7.......3...945.....3.7..4..5.2.....4.7..265......4...51253...2...
* PAIR E1: 2,9 BLK 2
D3: 2,9,4,5,8                            # reduction candidate for 2,9
D3: 2,9                                  # 16 pairs
E3: 2,9,6,8                              # reduction candidate for 2,9
E3: 2,9                                  # 15 pairs
* PAIR E1: 2,9 ROW 1
G1: 2,9,1,3                              # reduction candidate for 2,9
G1: 2,9 => SOLVED
* 413725986628419735759863124945271863376948251281536497192654378864397512537182649
* DURATION: 0:00:04.161666  START: 04:24:45.624891  END: 04:24:49.786557 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0050-base-pr-001.dot
* REASONING
* PRF # G1: 2,9 => SOL
* STA G1: 2,9
* CNT   1 HDP CHAINS /   3 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=50

Solution

position: 413725986628419735759863124945271863376948251281536497192654378864397512537182649 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 # D3: 2,9 => UNS
* INC # E3: 2,9 => UNS
* PRF # G1: 2,9 => SOL
* INC # G1: 1,3 => UNS
* DIS # G4: 2,6 => CTR => G4: 1,8
* INC # G4: 1,8 => UNS
* INC # G5: 2,6 => UNS
* INC # E4: 2,6 => UNS
* INC # E4: 7,8 => UNS
* INC # G5: 6,9 => UNS
* INC # G5: 1,2,8 => UNS
* INC # E6: 6,9 => UNS
* INC # F6: 6,9 => UNS
* INC # H9: 6,9 => UNS
* INC # H9: 4,7 => UNS
* CNT  15 HDP CHAINS /  15 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D3: 2,9 => UNS
* INC # E3: 2,9 => UNS
* PRF # G1: 2,9 => SOL
* STA G1: 2,9
* CNT   3 HDP CHAINS /   3 HYP OPENED