Analysis of zz-www.sudokuwiki.org-0058-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=58

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=58

position: ..18.....28....7.....1...9.5....9.7...8.2.4...3.6....2.2...3.....4.....5...9.61.. initial

Autosolve

position: ..18.....28....7.....1...9.5.2..9.7...8.2.4...3.6....2.2...3.....42....5...9.612. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E1: 4,5 => CTR => E1: 3,6,7,9
* DIS # E2: 4,5 => CTR => E2: 3,6,9
* DIS # E3: 4,5 => CTR => E3: 3,6,7
* PRF # A6: 7,9 => SOL
* DIS # C9: 5,7 => CTR => C9: 3
* PRF # E9: 5,7 => SOL
* CNT   6 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 # E1: 4,5 => CTR => E1: 3,6,7,9
* DIS E1: 3,6,7,9 # E2: 4,5 => CTR => E2: 3,6,9
* DIS E1: 3,6,7,9 + E2: 3,6,9 # E3: 4,5 => CTR => E3: 3,6,7
* PRF E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # A6: 7,9 => SOL
* STA E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 + A6: 7,9
* CNT   4 HDP CHAINS /  20 HYP OPENED

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

Details

Positions

..18.....28....7.....1...9.5....9.7...8.2.4...3.6....2.2...3.....4.....5...9.61.. initial
..18.....28....7.....1...9.5.2..9.7...8.2.4...3.6....2.2...3.....42....5...9.612. autosolve
371892546289564713465137298542389671618725439937641852126453987794218365853976124 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
F2: 4,5
C6: 7,9
D4: 3,4
B9: 5,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H2,I2: 1.. / H2 = 1  =>  5 pairs (_) / I2 = 1  =>  4 pairs (_)
A7,E7: 1.. / A7 = 1  =>  4 pairs (_) / E7 = 1  => 11 pairs (_)
F1,F3: 2.. / F1 = 2  =>  4 pairs (_) / F3 = 2  =>  4 pairs (_)
G1,G3: 2.. / G1 = 2  =>  4 pairs (_) / G3 = 2  =>  4 pairs (_)
F1,G1: 2.. / F1 = 2  =>  4 pairs (_) / G1 = 2  =>  4 pairs (_)
F3,G3: 2.. / F3 = 2  =>  4 pairs (_) / G3 = 2  =>  4 pairs (_)
B4,A6: 4.. / B4 = 4  => 12 pairs (_) / A6 = 4  =>  6 pairs (_)
E9,I9: 4.. / E9 = 4  =>  5 pairs (_) / I9 = 4  =>  0 pairs (*)
I7,I9: 7.. / I7 = 7  =>  0 pairs (*) / I9 = 7  =>  0 pairs (X)
D5,D7: 7.. / D5 = 7  =>  7 pairs (_) / D7 = 7  =>  8 pairs (_)
G3,I3: 8.. / G3 = 8  =>  7 pairs (_) / I3 = 8  =>  4 pairs (_)
F6,F8: 8.. / F6 = 8  =>  9 pairs (_) / F8 = 8  =>  6 pairs (_)
E1,E2: 9.. / E1 = 9  =>  5 pairs (_) / E2 = 9  =>  4 pairs (_)
I5,G6: 9.. / I5 = 9  =>  5 pairs (_) / G6 = 9  =>  0 pairs (X)
C2,E2: 9.. / C2 = 9  =>  5 pairs (_) / E2 = 9  =>  4 pairs (_)
I5,I7: 9.. / I5 = 9  =>  5 pairs (_) / I7 = 9  =>  0 pairs (X)
* DURATION: 0:00:17.095149  START: 04:28:23.702931  END: 04:28:40.798080 2017-05-01
* CP COUNT: (16)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,C6,D4,F2)
* ..18.....28....7.....1...9.5.2..9.7...8.2.4...3.6....2.2...3.....42....5...9.612.
* PAIR F2: 4,5 BLK 2
E1: 4,5,3,6,7,9                          # reduction candidate for 4,5
E1: 4,5 => CTR
* ..185....28.3947.....16..9.5.2439.7...872.4..4376..9.2.295.36....42..385...9.612.
E1: 3,6,7,9                              #  4 pairs
F1: 4,5,2,7                              # reduction candidate for 4,5
F1: 4,5                                  # 15 pairs
D2: 4,5,3                                # reduction candidate for 4,5
D2: 4,5                                  # 10 pairs
E2: 4,5,3,6,9                            # reduction candidate for 4,5
E2: 4,5 => CTR
* ..189....2893547.....16..985.2439671..8.2.4..4376..9.2.26..3849..42....5...946127
E2: 3,6,9                                #  4 pairs
E3: 4,5,3,6,7                            # reduction candidate for 4,5
E3: 4,5 => CTR
* ..18..5..28.3.47.....15..9.5.2439.7...872.4..4376..9.2.2.5.3..9..42....5...9.6127
E3: 3,6,7                                #  4 pairs
F3: 4,5,2,7                              # reduction candidate for 4,5
F3: 4,5                                  # 15 pairs
* PAIR F2: 4,5 ROW 2
H2: 4,5,1,3,6                            # reduction candidate for 4,5
H2: 4,5                                  # 14 pairs
H2: 1,3,6                                #  4 pairs
* PAIR F2: 4,5 COL F
F6: 4,5,1,7,8                            # reduction candidate for 4,5
F6: 4,5                                  # 13 pairs
F6: 1,7,8                                #  5 pairs
* PAIR C6: 7,9 BLK 4
A5: 7,9,1,6                              # reduction candidate for 7,9
A5: 7,9                                  #  7 pairs
B5: 7,9,1,6                              # reduction candidate for 7,9
B5: 7,9                                  #  7 pairs
A6: 7,9,1,4                              # reduction candidate for 7,9
A6: 7,9 => SOLVED
* 371892546289564713465137298542389671618725439937641852126453987794218365853976124
A6: 1,4                                  #  5 pairs
* PAIR C6: 7,9 COL C
C7: 7,9,5,6                              # reduction candidate for 7,9
C7: 7,9                                  #  6 pairs
C7: 5,6                                  #  5 pairs
* PAIR D4: 3,4 BLK 5
E4: 3,4,1,8                              # reduction candidate for 3,4
E4: 3,4                                  # 12 pairs
E4: 1,8                                  # 11 pairs
* PAIR D4: 3,4 COL D
D2: 3,4,5                                # reduction candidate for 3,4
D2: 5                                    # 10 pairs
D2: 3,4                                  #  8 pairs
* PAIR B9: 5,7 BLK 7
C7: 5,7,6,9                              # reduction candidate for 5,7
C7: 5,7                                  # 12 pairs
C9: 5,7,3                                # reduction candidate for 5,7
C9: 5,7 => CTR
* ..18...4.28.5.47..4..1...9.542319.7...8725439.3.648..2.2.453..7..42....5...986124
C9: 3                                    #  5 pairs
* PAIR B9: 5,7 ROW 9
E9: 5,7,4,8                              # reduction candidate for 5,7
E9: 5,7 => SOLVED
* 371892546289564713465137298542389671618725439937641852126453987794218365853976124
E9: 4,8                                  #  5 pairs
* PAIR B9: 5,7 COL B
B1: 5,7,4,6,9                            # reduction candidate for 5,7
B1: 5,7                                  #  6 pairs
B3: 5,7,4,6                              # reduction candidate for 5,7
B3: 5,7                                  #  5 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0058-base-pr-000.dot
* REASONING
* DIS # E1: 4,5 => CTR => E1: 3,6,7,9
* DIS # E2: 4,5 => CTR => E2: 3,6,9
* DIS # E3: 4,5 => CTR => E3: 3,6,7
* PRF # A6: 7,9 => SOL
* DIS # C9: 5,7 => CTR => C9: 3
* PRF # E9: 5,7 => SOL
* CNT   6 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,C6,D4,F2)
* ..18.....28....7.....1...9.5.2..9.7...8.2.4...3.6....2.2...3.....42....5...9.612.
* PAIR F2: 4,5 BLK 2
E1: 4,5,3,6,7,9                          # reduction candidate for 4,5
E1: 4,5 => CTR
* ..185....28.3947.....16..9.5.2439.7...872.4..4376..9.2.295.36....42..385...9.612.
F1: 4,5,2,7                              # reduction candidate for 4,5
F1: 4,5                                  # 15 pairs
D2: 4,5,3                                # reduction candidate for 4,5
D2: 4,5                                  # 10 pairs
E2: 4,5,3,6,9                            # reduction candidate for 4,5
E2: 4,5 => CTR
* ..189....2893547.....16..985.2439671..8.2.4..4376..9.2.26..3849..42....5...946127
E3: 4,5,3,6,7                            # reduction candidate for 4,5
E3: 4,5 => CTR
* ..18..5..28.3.47.....15..9.5.2439.7...872.4..4376..9.2.2.5.3..9..42....5...9.6127
F3: 4,5,2,7                              # reduction candidate for 4,5
F3: 4,5                                  # 15 pairs
* PAIR F2: 4,5 ROW 2
H2: 4,5,1,3,6                            # reduction candidate for 4,5
H2: 4,5                                  # 17 pairs
H2: 1,3,6                                #  4 pairs
* PAIR F2: 4,5 COL F
F6: 4,5,1,7,8                            # reduction candidate for 4,5
F6: 4,5                                  # 16 pairs
F6: 1,7,8                                #  5 pairs
* PAIR RESTART
* PAIR F2: 4,5 BLK 2
F1: 4,5,2,7                              # reduction candidate for 4,5
F1: 4,5                                  # 15 pairs
D2: 4,5,3                                # reduction candidate for 4,5
D2: 4,5                                  # 10 pairs
F3: 4,5,2,7                              # reduction candidate for 4,5
F3: 4,5                                  # 15 pairs
* PAIR F2: 4,5 ROW 2
H2: 4,5,1,3,6                            # reduction candidate for 4,5
H2: 4,5                                  # 17 pairs
H2: 1,3,6                                #  4 pairs
* PAIR F2: 4,5 COL F
F6: 4,5,1,7,8                            # reduction candidate for 4,5
F6: 4,5                                  # 16 pairs
F6: 1,7,8                                #  5 pairs
* PAIR C6: 7,9 BLK 4
A5: 7,9,1,6                              # reduction candidate for 7,9
A5: 7,9                                  #  7 pairs
B5: 7,9,1,6                              # reduction candidate for 7,9
B5: 7,9                                  #  7 pairs
A6: 7,9,1,4                              # reduction candidate for 7,9
A6: 7,9 => SOLVED
* 371892546289564713465137298542389671618725439937641852126453987794218365853976124
* DURATION: 0:00:15.971616  START: 04:28:59.399511  END: 04:29:15.371127 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0058-base-pr-001.dot
* REASONING
* DIS # E1: 4,5 => CTR => E1: 3,6,7,9
* DIS E1: 3,6,7,9 # E2: 4,5 => CTR => E2: 3,6,9
* DIS E1: 3,6,7,9 + E2: 3,6,9 # E3: 4,5 => CTR => E3: 3,6,7
* PRF E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # A6: 7,9 => SOL
* STA E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 + A6: 7,9
* CNT   4 HDP CHAINS /  20 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=58

Solution

position: 371892546289564713465137298542389671618725439937641852126453987794218365853976124 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 # E1: 4,5 => CTR => E1: 3,6,7,9
* INC # E1: 3,6,7,9 => UNS
* INC # F1: 4,5 => UNS
* INC # D2: 4,5 => UNS
* DIS # E2: 4,5 => CTR => E2: 3,6,9
* INC # E2: 3,6,9 => UNS
* DIS # E3: 4,5 => CTR => E3: 3,6,7
* INC # E3: 3,6,7 => UNS
* INC # F3: 4,5 => UNS
* INC # H2: 4,5 => UNS
* INC # H2: 1,3,6 => UNS
* INC # F6: 4,5 => UNS
* INC # F6: 1,7,8 => UNS
* INC # A5: 7,9 => UNS
* INC # B5: 7,9 => UNS
* PRF # A6: 7,9 => SOL
* INC # A6: 1,4 => UNS
* INC # C7: 7,9 => UNS
* INC # C7: 5,6 => UNS
* INC # E4: 3,4 => UNS
* INC # E4: 1,8 => UNS
* INC # D2: 3,4 => UNS
* INC # D2: 5 => UNS
* INC # C7: 5,7 => UNS
* DIS # C9: 5,7 => CTR => C9: 3
* INC # C9: 3 => UNS
* PRF # E9: 5,7 => SOL
* INC # E9: 4,8 => UNS
* INC # B1: 5,7 => UNS
* INC # B3: 5,7 => UNS
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # E1: 4,5 => CTR => E1: 3,6,7,9
* INC E1: 3,6,7,9 # F1: 4,5 => UNS
* INC E1: 3,6,7,9 # D2: 4,5 => UNS
* DIS E1: 3,6,7,9 # E2: 4,5 => CTR => E2: 3,6,9
* DIS E1: 3,6,7,9 + E2: 3,6,9 # E3: 4,5 => CTR => E3: 3,6,7
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F3: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # H2: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # H2: 1,3,6 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F6: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F6: 1,7,8 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F1: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # D2: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F3: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # H2: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # H2: 1,3,6 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F6: 4,5 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # F6: 1,7,8 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # A5: 7,9 => UNS
* INC E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # B5: 7,9 => UNS
* PRF E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 # A6: 7,9 => SOL
* STA E1: 3,6,7,9 + E2: 3,6,9 + E3: 3,6,7 + A6: 7,9
* CNT  20 HDP CHAINS /  20 HYP OPENED