Analysis of zz-www.sudokuwiki.org-0089-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=89

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=89

position: ......7....6.9..54...5.2.1...28....5.5.....3.8....64...8.3.9...91..4.6....4...... initial

Autosolve

position: ......7....6.9..54...5.2.1...28....5.5.....3.8...564...8.3.9.4.91..4.6....4...... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F2: 1,7 => CTR => F2: 3,8
* DIS # D5: 1,7 => CTR => D5: 2,4,9
* DIS # D6: 1,7 => CTR => D6: 2,9
* DIS # G5: 1,9 => CTR => G5: 2,8
* PRF # A7: 5,7 => SOL
* DIS # E7: 2,7 => CTR => E7: 1,6
* DIS # E9: 2,7 => CTR => E9: 1,6,8
* DIS # D5: 2,7 => CTR => D5: 1,4,9
* DIS # D6: 2,7 => CTR => D6: 1,9
* CNT   9 HDP CHAINS /  30 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 # F2: 1,7 => CTR => F2: 3,8
* PRF F2: 3,8 # A2: 2,3 => SOL
* STA F2: 3,8 + A2: 2,3
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

......7....6.9..54...5.2.1...28....5.5.....3.8....64...8.3.9...91..4.6....4...... initial
......7....6.9..54...5.2.1...28....5.5.....3.8...564...8.3.9.4.91..4.6....4...... autosolve
125634789376198254498572316742813965659427831831956427587369142913245678264781593 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
D2: 1,7
G4: 1,9
C7: 5,7
D8: 2,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B6,C6: 3.. / B6 = 3  =>  6 pairs (_) / C6 = 3  =>  9 pairs (_)
E4,F4: 3.. / E4 = 3  =>  4 pairs (_) / F4 = 3  =>  5 pairs (_)
C8,I8: 3.. / C8 = 3  =>  6 pairs (_) / I8 = 3  =>  7 pairs (_)
A3,B3: 4.. / A3 = 4  => 10 pairs (_) / B3 = 4  =>  5 pairs (_)
D1,F1: 4.. / D1 = 4  =>  0 pairs (X) / F1 = 4  =>  8 pairs (_)
B3,B4: 4.. / B3 = 4  =>  5 pairs (_) / B4 = 4  => 10 pairs (_)
D1,D5: 4.. / D1 = 4  =>  0 pairs (X) / D5 = 4  =>  8 pairs (_)
A1,C1: 5.. / A1 = 5  =>  4 pairs (_) / C1 = 5  => 11 pairs (_)
F8,F9: 5.. / F8 = 5  =>  5 pairs (_) / F9 = 5  =>  7 pairs (_)
G7,G9: 5.. / G7 = 5  =>  7 pairs (_) / G9 = 5  =>  6 pairs (_)
C8,F8: 5.. / C8 = 5  =>  7 pairs (_) / F8 = 5  =>  5 pairs (_)
H4,I5: 6.. / H4 = 6  =>  7 pairs (_) / I5 = 6  =>  0 pairs (X)
E3,I3: 6.. / E3 = 6  =>  0 pairs (X) / I3 = 6  =>  7 pairs (_)
A5,I5: 6.. / A5 = 6  =>  7 pairs (_) / I5 = 6  =>  0 pairs (X)
A7,E7: 6.. / A7 = 6  =>  0 pairs (X) / E7 = 6  =>  7 pairs (_)
B4,B9: 6.. / B4 = 6  =>  0 pairs (X) / B9 = 6  =>  7 pairs (_)
D1,D9: 6.. / D1 = 6  =>  7 pairs (_) / D9 = 6  =>  0 pairs (X)
H1,H4: 6.. / H1 = 6  =>  0 pairs (X) / H4 = 6  =>  7 pairs (_)
C1,C3: 8.. / C1 = 8  =>  8 pairs (_) / C3 = 8  =>  5 pairs (_)
G5,I5: 8.. / G5 = 8  =>  7 pairs (_) / I5 = 8  =>  0 pairs (X)
F2,G2: 8.. / F2 = 8  =>  6 pairs (_) / G2 = 8  =>  0 pairs (X)
D5,D6: 9.. / D5 = 9  =>  0 pairs (X) / D6 = 9  =>  6 pairs (_)
* DURATION: 0:00:28.104784  START: 05:03:34.247345  END: 05:04:02.352129 2017-05-01
* CP COUNT: (22)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C7,D2,D8,G4)
* ......7....6.9..54...5.2.1...28....5.5.....3.8...564...8.3.9.4.91..4.6....4......
* PAIR D2: 1,7 BLK 2
F2: 1,7,3,8                              # reduction candidate for 1,7
F2: 1,7 => CTR
* .9.6.4723..6.9.854...5.2.16..28.3.6565.42..388..9564...8.369.4.91..4.6...64......
F2: 3,8                                  #  5 pairs
* PAIR D2: 1,7 ROW 2
A2: 1,7,2,3                              # reduction candidate for 1,7
A2: 2,3                                  # 11 pairs
A2: 1,7                                  #  7 pairs
* PAIR D2: 1,7 COL D
D5: 1,7,2,4,9                            # reduction candidate for 1,7
D5: 1,7 => CTR
* .9.4..76.1.6798.54.4.562.1..628..195.5912.8368319564..68.3.9.4.91.24.68..7468..2.
D5: 2,4,9                                #  4 pairs
D6: 1,7,2,9                              # reduction candidate for 1,7
D6: 1,7 => CTR
* ...4..76.1.6798.54347562918.628..195.5192.8368..156427685379.4.91.24.68...468....
D6: 2,9                                  #  5 pairs
D9: 1,7,2,6                              # reduction candidate for 1,7
D9: 1,7                                  #  8 pairs
* PAIR G4: 1,9 BLK 6
G5: 1,9,2,8                              # reduction candidate for 1,9
G5: 1,9 => CTR
* 1256.47..3761982544985723167428.39656594271388319564..287369541913.4568..64......
G5: 2,8                                  #  5 pairs
I5: 1,9,2,6,7,8                          # reduction candidate for 1,9
I5: 1,9                                  # 18 pairs
I6: 1,9,2,7                              # reduction candidate for 1,9
I6: 1,9                                  #  8 pairs
* PAIR G4: 1,9 COL G
G9: 1,9,2,3,5,8                          # reduction candidate for 1,9
G9: 1,9                                  # 10 pairs
G9: 2,3,5,8                              #  4 pairs
* PAIR C7: 5,7 BLK 7
A7: 5,7,2,6                              # reduction candidate for 5,7
A7: 5,7 => SOLVED
* 125634789376198254498572316742813965659427831831956427587369142913245678264781593
A7: 2,6                                  #  5 pairs
C8: 5,7,3                                # reduction candidate for 5,7
C8: 5,7                                  #  7 pairs
A9: 5,7,2,3,6                            # reduction candidate for 5,7
A9: 5,7                                  #  9 pairs
* PAIR D8: 2,7 BLK 8
E7: 2,7,1,6                              # reduction candidate for 2,7
E7: 2,7 => CTR
* 5.....76.1.6798.54347562918.628..195.5..2.8368...5642768537924191324568.2.46815..
E7: 1,6                                  #  5 pairs
D9: 2,7,1,6                              # reduction candidate for 2,7
D9: 2,7                                  # 18 pairs
E9: 2,7,1,6,8                            # reduction candidate for 2,7
E9: 2,7 => CTR
* .9.6.472..2679.854...5.2316..28...6565.42..388319564...8.369.4191.24.6...6417....
E9: 1,6,8                                #  4 pairs
* PAIR D8: 2,7 ROW 8
H8: 2,7,8                                # reduction candidate for 2,7
H8: 2,7                                  #  8 pairs
I8: 2,7,3,8                              # reduction candidate for 2,7
I8: 2,7                                  #  7 pairs
* PAIR D8: 2,7 COL D
D5: 2,7,1,4,9                            # reduction candidate for 2,7
D5: 2,7 => CTR
* ...4..76...619..54.4.562.1..628....5.59...8368..9564..68.3.9.4.91..4.6....46.....
D5: 1,4,9                                #  4 pairs
D6: 2,7,1,9                              # reduction candidate for 2,7
D6: 2,7 => CTR
* ...4..76...619..54.4.562.1..628....5.5.9..8368...564..68.3.9.4.91..4.6....46.....
D6: 1,9                                  #  5 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0089-base-pr-000.dot
* REASONING
* DIS # F2: 1,7 => CTR => F2: 3,8
* DIS # D5: 1,7 => CTR => D5: 2,4,9
* DIS # D6: 1,7 => CTR => D6: 2,9
* DIS # G5: 1,9 => CTR => G5: 2,8
* PRF # A7: 5,7 => SOL
* DIS # E7: 2,7 => CTR => E7: 1,6
* DIS # E9: 2,7 => CTR => E9: 1,6,8
* DIS # D5: 2,7 => CTR => D5: 1,4,9
* DIS # D6: 2,7 => CTR => D6: 1,9
* CNT   9 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C7,D2,D8,G4)
* ......7....6.9..54...5.2.1...28....5.5.....3.8...564...8.3.9.4.91..4.6....4......
* PAIR D2: 1,7 BLK 2
F2: 1,7,3,8                              # reduction candidate for 1,7
F2: 1,7 => CTR
* .9.6.4723..6.9.854...5.2.16..28.3.6565.42..388..9564...8.369.4.91..4.6...64......
* PAIR D2: 1,7 ROW 2
A2: 1,7,2,3                              # reduction candidate for 1,7
A2: 2,3 => SOLVED
* 125634789376198254498572316742813965659427831831956427587369142913245678264781593
* DURATION: 0:00:04.260860  START: 05:04:22.878167  END: 05:04:27.139027 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0089-base-pr-001.dot
* REASONING
* DIS # F2: 1,7 => CTR => F2: 3,8
* PRF F2: 3,8 # A2: 2,3 => SOL
* STA F2: 3,8 + A2: 2,3
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=89

Solution

position: 125634789376198254498572316742813965659427831831956427587369142913245678264781593 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:

* DIS # F2: 1,7 => CTR => F2: 3,8
* INC # F2: 3,8 => UNS
* INC # A2: 1,7 => UNS
* INC # A2: 2,3 => UNS
* DIS # D5: 1,7 => CTR => D5: 2,4,9
* INC # D5: 2,4,9 => UNS
* DIS # D6: 1,7 => CTR => D6: 2,9
* INC # D6: 2,9 => UNS
* INC # D9: 1,7 => UNS
* DIS # G5: 1,9 => CTR => G5: 2,8
* INC # G5: 2,8 => UNS
* INC # I5: 1,9 => UNS
* INC # I6: 1,9 => UNS
* INC # G9: 1,9 => UNS
* INC # G9: 2,3,5,8 => UNS
* PRF # A7: 5,7 => SOL
* INC # A7: 2,6 => UNS
* INC # C8: 5,7 => UNS
* INC # A9: 5,7 => UNS
* DIS # E7: 2,7 => CTR => E7: 1,6
* INC # E7: 1,6 => UNS
* INC # D9: 2,7 => UNS
* DIS # E9: 2,7 => CTR => E9: 1,6,8
* INC # E9: 1,6,8 => UNS
* INC # H8: 2,7 => UNS
* INC # I8: 2,7 => UNS
* DIS # D5: 2,7 => CTR => D5: 1,4,9
* INC # D5: 1,4,9 => UNS
* DIS # D6: 2,7 => CTR => D6: 1,9
* INC # D6: 1,9 => UNS
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # F2: 1,7 => CTR => F2: 3,8
* INC F2: 3,8 # A2: 1,7 => UNS
* PRF F2: 3,8 # A2: 2,3 => SOL
* STA F2: 3,8 + A2: 2,3
* CNT   3 HDP CHAINS /   3 HYP OPENED