Analysis of zz-www.sudokuwiki.org-0073-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=73

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=73

position: ..9..8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5.. initial

Autosolve

position: ..93.8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F4: 1,5 => CTR => F4: 2,6
* DIS # G7: 3,6 => CTR => G7: 1,4,7
* CNT   2 HDP CHAINS /  17 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 # F4: 1,5 => CTR => F4: 2,6
* PRF F4: 2,6 # H6: 1,5 => SOL
* STA F4: 2,6 + H6: 1,5
* CNT   2 HDP CHAINS /  12 HYP OPENED

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

Details

Positions

..9..8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5.. initial
..93.8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5.. autosolve
759328641148657932263941785835496217924715368617283459386579124572134896491862573 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (3)
B1: 4,5
H4: 1,5
I9: 3,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I2,I3: 2.. / I2 = 2  =>  4 pairs (_) / I3 = 2  =>  0 pairs (X)
G4,G6: 2.. / G4 = 2  =>  3 pairs (_) / G6 = 2  =>  0 pairs (X)
E9,F9: 2.. / E9 = 2  =>  4 pairs (_) / F9 = 2  =>  3 pairs (_)
A1,E1: 2.. / A1 = 2  =>  4 pairs (_) / E1 = 2  =>  4 pairs (_)
D2,D6: 2.. / D2 = 2  =>  0 pairs (X) / D6 = 2  =>  3 pairs (_)
A3,C3: 3.. / A3 = 3  =>  4 pairs (_) / C3 = 3  =>  9 pairs (_)
E7,F8: 4.. / E7 = 4  => 23 pairs (_) / F8 = 4  =>  5 pairs (_)
I3,I5: 5.. / I3 = 5  =>  5 pairs (_) / I5 = 5  =>  0 pairs (X)
G1,I2: 6.. / G1 = 6  =>  3 pairs (_) / I2 = 6  =>  0 pairs (X)
E4,F4: 6.. / E4 = 6  => 14 pairs (_) / F4 = 6  =>  3 pairs (_)
C7,C9: 6.. / C7 = 6  =>  9 pairs (_) / C9 = 6  =>  4 pairs (_)
E1,G1: 6.. / E1 = 6  =>  0 pairs (X) / G1 = 6  =>  3 pairs (_)
G7,H9: 7.. / G7 = 7  =>  8 pairs (_) / H9 = 7  =>  9 pairs (_)
E5,E6: 8.. / E5 = 8  =>  5 pairs (_) / E6 = 8  =>  3 pairs (_)
B7,C7: 8.. / B7 = 8  =>  6 pairs (_) / C7 = 8  =>  4 pairs (_)
B2,B7: 8.. / B2 = 8  =>  4 pairs (_) / B7 = 8  =>  6 pairs (_)
B4,A5: 9.. / B4 = 9  => 14 pairs (_) / A5 = 9  =>  5 pairs (_)
E4,E5: 9.. / E4 = 9  =>  5 pairs (_) / E5 = 9  => 14 pairs (_)
A8,B9: 9.. / A8 = 9  => 14 pairs (_) / B9 = 9  =>  5 pairs (_)
H8,H9: 9.. / H8 = 9  =>  5 pairs (_) / H9 = 9  => 14 pairs (_)
B4,E4: 9.. / B4 = 9  => 14 pairs (_) / E4 = 9  =>  5 pairs (_)
A5,E5: 9.. / A5 = 9  =>  5 pairs (_) / E5 = 9  => 14 pairs (_)
A8,H8: 9.. / A8 = 9  => 14 pairs (_) / H8 = 9  =>  5 pairs (_)
B9,H9: 9.. / B9 = 9  =>  5 pairs (_) / H9 = 9  => 14 pairs (_)
A5,A8: 9.. / A5 = 9  =>  5 pairs (_) / A8 = 9  => 14 pairs (_)
B4,B9: 9.. / B4 = 9  => 14 pairs (_) / B9 = 9  =>  5 pairs (_)
* DURATION: 0:00:29.856891  START: 04:43:38.961919  END: 04:44:08.818810 2017-05-01
* CP COUNT: (26)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,H4,I9)
* ..93.8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5..
* PAIR B1: 4,5 BLK 1
C3: 4,5,1,3,7,8                          # reduction candidate for 4,5
C3: 4,5                                  #  7 pairs
C3: 1,3,7,8                              #  3 pairs
* PAIR B1: 4,5 ROW 1
H1: 4,5,7                                # reduction candidate for 4,5
H1: 7                                    #  9 pairs
H1: 4,5                                  #  6 pairs
* PAIR B1: 4,5 COL B
B6: 4,5,1                                # reduction candidate for 4,5
B6: 1                                    #  6 pairs
B6: 4,5                                  #  5 pairs
* PAIR H4: 1,5 BLK 6
H6: 1,5,4,8                              # reduction candidate for 1,5
H6: 1,5                                  #  8 pairs
H6: 4,8                                  #  4 pairs
* PAIR H4: 1,5 ROW 4
B4: 1,5,3,9                              # reduction candidate for 1,5
B4: 1,5                                  # 10 pairs
C4: 1,5,3                                # reduction candidate for 1,5
C4: 1,5                                  #  7 pairs
F4: 1,5,2,6                              # reduction candidate for 1,5
F4: 1,5 => CTR
* ..93.86.1....5.93.36.9....589346.2.7.24.9.3686.7283..9..5..972.972.3....4.68..593
F4: 2,6                                  #  4 pairs
* PAIR I9: 3,6 BLK 9
G7: 3,6,1,4,7                            # reduction candidate for 3,6
G7: 3,6 => CTR
* ..9368..1....5.936.6.94...28..4962.792...5.636....3..9.....9.2457263419849.8..57.
G7: 1,4,7                                #  3 pairs
I7: 3,6,4                                # reduction candidate for 3,6
I7: 3,6                                  # 23 pairs
* PAIR I9: 3,6 ROW 9
C9: 3,6,1                                # reduction candidate for 3,6
C9: 1                                    # 12 pairs
C9: 3,6                                  #  5 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0073-base-pr-000.dot
* REASONING
* DIS # F4: 1,5 => CTR => F4: 2,6
* DIS # G7: 3,6 => CTR => G7: 1,4,7
* CNT   2 HDP CHAINS /  17 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,H4,I9)
* ..93.8..1....5.93..6.9.....8..4....7.2.....6.6....3..9.....9.2..72.3....4..8..5..
* PAIR B1: 4,5 BLK 1
C3: 4,5,1,3,7,8                          # reduction candidate for 4,5
C3: 4,5                                  #  7 pairs
C3: 1,3,7,8                              #  3 pairs
* PAIR B1: 4,5 ROW 1
H1: 4,5,7                                # reduction candidate for 4,5
H1: 7                                    #  9 pairs
H1: 4,5                                  #  6 pairs
* PAIR B1: 4,5 COL B
B6: 4,5,1                                # reduction candidate for 4,5
B6: 1                                    #  6 pairs
B6: 4,5                                  #  5 pairs
* PAIR H4: 1,5 BLK 6
H6: 1,5,4,8                              # reduction candidate for 1,5
H6: 1,5                                  #  8 pairs
H6: 4,8                                  #  4 pairs
* PAIR H4: 1,5 ROW 4
B4: 1,5,3,9                              # reduction candidate for 1,5
B4: 1,5                                  # 10 pairs
C4: 1,5,3                                # reduction candidate for 1,5
C4: 1,5                                  #  7 pairs
F4: 1,5,2,6                              # reduction candidate for 1,5
F4: 1,5 => CTR
* ..93.86.1....5.93.36.9....589346.2.7.24.9.3686.7283..9..5..972.972.3....4.68..593
* PAIR RESTART
* PAIR H4: 1,5 BLK 6
H6: 1,5,4,8                              # reduction candidate for 1,5
H6: 1,5 => SOLVED
* 759328641148657932263941785835496217924715368617283459386579124572134896491862573
* DURATION: 0:00:08.942085  START: 04:44:20.299307  END: 04:44:29.241392 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0073-base-pr-001.dot
* REASONING
* DIS # F4: 1,5 => CTR => F4: 2,6
* PRF F4: 2,6 # H6: 1,5 => SOL
* STA F4: 2,6 + H6: 1,5
* CNT   2 HDP CHAINS /  12 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=73

Solution

position: 759328641148657932263941785835496217924715368617283459386579124572134896491862573 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 # C3: 4,5 => UNS
* INC # C3: 1,3,7,8 => UNS
* INC # H1: 4,5 => UNS
* INC # H1: 7 => UNS
* INC # B6: 4,5 => UNS
* INC # B6: 1 => UNS
* INC # H6: 1,5 => UNS
* INC # H6: 4,8 => UNS
* INC # B4: 1,5 => UNS
* INC # C4: 1,5 => UNS
* DIS # F4: 1,5 => CTR => F4: 2,6
* INC # F4: 2,6 => UNS
* DIS # G7: 3,6 => CTR => G7: 1,4,7
* INC # G7: 1,4,7 => UNS
* INC # I7: 3,6 => UNS
* INC # C9: 3,6 => UNS
* INC # C9: 1 => UNS
* CNT  17 HDP CHAINS /  17 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C3: 4,5 => UNS
* INC # C3: 1,3,7,8 => UNS
* INC # H1: 4,5 => UNS
* INC # H1: 7 => UNS
* INC # B6: 4,5 => UNS
* INC # B6: 1 => UNS
* INC # H6: 1,5 => UNS
* INC # H6: 4,8 => UNS
* INC # B4: 1,5 => UNS
* INC # C4: 1,5 => UNS
* DIS # F4: 1,5 => CTR => F4: 2,6
* PRF F4: 2,6 # H6: 1,5 => SOL
* STA F4: 2,6 + H6: 1,5
* CNT  12 HDP CHAINS /  12 HYP OPENED