Analysis of zz-www.sudokuoftheday.co.uk-20060611-absurd-base.sdk

Contents

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Jun&YEAR=2006

level: medium

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Jun&YEAR=2006

position: .736......2....4735........25.1....8369.8.......264..9.1.....5....8.12......5.6.. initial

Autosolve

position: .736....5.26...4735.......62541..768369.8.142.8.264539.1...635.6.58.129.....5.681 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D3: 4,9 => CTR => D3: 3,7
* PRF # E3: 4,9 => SOL
* DIS # B9: 3 => CTR => B9: 4,9
* DIS # F2: 5,9 => CTR => F2: 8
* DIS # E1: 1,9 => CTR => E1: 2,4
* PRF # E3: 1,9 => SOL
* DIS # A2: 8 => CTR => A2: 1,9
* PRF # A1: 8,9 => SOL
* DIS # E1: 1,2 => CTR => E1: 4,9
* DIS # F3: 8,9 => CTR => F3: 2,3,7
* DIS # E3: 1,2 => CTR => E3: 3,4,7,9
* DIS # B9: 3,4 => CTR => B9: 9
* DIS # C7: 2,7 => CTR => C7: 8
* DIS # E7: 4,7 => CTR => E7: 2,9
* DIS # E8: 3 => CTR => E8: 4,7
* CNT  15 HDP CHAINS /  45 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 # D3: 4,9 => CTR => D3: 3,7
* PRF D3: 3,7 # E3: 4,9 => SOL
* STA D3: 3,7 + E3: 4,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.736......2....4735........25.1....8369.8.......264..9.1.....5....8.12......5.6.. initial
.736....5.26...4735.......62541..768369.8.142.8.264539.1...635.6.58.129.....5.681 autosolve
873642915926518473541397826254139768369785142187264539418926357635871294792453681 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (18)
B3: 4,9
C3: 1,8
D2: 5,9
E2: 1,9
G1: 8,9
H1: 1,2
G3: 8,9
H3: 1,2
A6: 1,7
C6: 1,7
E4: 3,9
F4: 3,9
D5: 5,7
F5: 5,7
B8: 3,4
C9: 2,7
I7: 4,7
I8: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H1,H3: 1.. / H1 = 1  => 16 pairs (_) / H3 = 1  =>  0 pairs (X)
A6,C6: 1.. / A6 = 1  => 13 pairs (_) / C6 = 1  =>  0 pairs (X)
A2,E2: 1.. / A2 = 1  =>  0 pairs (X) / E2 = 1  => 18 pairs (_)
C3,C6: 1.. / C3 = 1  => 13 pairs (_) / C6 = 1  =>  0 pairs (X)
H1,H3: 2.. / H1 = 2  =>  0 pairs (X) / H3 = 2  => 16 pairs (_)
C7,C9: 2.. / C7 = 2  =>  0 pairs (X) / C9 = 2  => 18 pairs (_)
E7,F9: 2.. / E7 = 2  => 18 pairs (_) / F9 = 2  =>  0 pairs (X)
C7,E7: 2.. / C7 = 2  =>  0 pairs (X) / E7 = 2  => 18 pairs (_)
C9,F9: 2.. / C9 = 2  => 18 pairs (_) / F9 = 2  =>  0 pairs (X)
E4,F4: 3.. / E4 = 3  => 19 pairs (_) / F4 = 3  => 17 pairs (_)
B8,B9: 3.. / B8 = 3  => 19 pairs (_) / B9 = 3  =>  0 pairs (X)
B8,E8: 3.. / B8 = 3  => 19 pairs (_) / E8 = 3  =>  0 pairs (X)
D3,D9: 3.. / D3 = 3  => 19 pairs (_) / D9 = 3  => 19 pairs (_)
A1,B3: 4.. / A1 = 4  =>  0 pairs (X) / B3 = 4  => 21 pairs (_)
I7,I8: 4.. / I7 = 4  => 20 pairs (_) / I8 = 4  => 18 pairs (_)
A1,E1: 4.. / A1 = 4  =>  0 pairs (X) / E1 = 4  => 21 pairs (_)
D2,F2: 5.. / D2 = 5  => 17 pairs (_) / F2 = 5  =>  0 pairs (X)
D5,F5: 5.. / D5 = 5  =>  0 pairs (X) / F5 = 5  => 17 pairs (_)
D2,D5: 5.. / D2 = 5  => 17 pairs (_) / D5 = 5  =>  0 pairs (X)
F2,F5: 5.. / F2 = 5  =>  0 pairs (X) / F5 = 5  => 17 pairs (_)
A6,C6: 7.. / A6 = 7  =>  0 pairs (X) / C6 = 7  => 13 pairs (_)
D5,F5: 7.. / D5 = 7  => 17 pairs (_) / F5 = 7  =>  0 pairs (X)
I7,I8: 7.. / I7 = 7  => 18 pairs (_) / I8 = 7  => 20 pairs (_)
E8,I8: 7.. / E8 = 7  => 18 pairs (_) / I8 = 7  => 20 pairs (_)
G1,G3: 8.. / G1 = 8  => 22 pairs (_) / G3 = 8  =>  0 pairs (*)
A7,C7: 8.. / A7 = 8  =>  0 pairs (X) / C7 = 8  => 13 pairs (_)
A2,F2: 8.. / A2 = 8  =>  0 pairs (X) / F2 = 8  => 18 pairs (_)
C3,C7: 8.. / C3 = 8  =>  0 pairs (X) / C7 = 8  => 13 pairs (_)
G1,G3: 9.. / G1 = 9  =>  0 pairs (*) / G3 = 9  =>  0 pairs (X)
E4,F4: 9.. / E4 = 9  => 17 pairs (_) / F4 = 9  => 19 pairs (_)
B3,B9: 9.. / B3 = 9  =>  0 pairs (X) / B9 = 9  => 21 pairs (_)
* DURATION: 0:00:33.956077  START: 23:45:52.440576  END: 23:46:26.396653 2019-04-30
* CP COUNT: (31)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,B3,B8,C3,C6,C9,D2,D5,E2,E4,F4,F5,G1,G3,H1,H3,I7,I8)
* .736....5.26...4735.......62541..768369.8.142.8.264539.1...635.6.58.129.....5.681
* PAIR B3: 4,9 BLK 1
A1: 4,9,1,8                              # reduction candidate for 4,9
A1: 4,9                                  # 21 pairs
A1: 1,8                                  # 20 pairs
* PAIR B3: 4,9 ROW 3
D3: 4,9,3,7                              # reduction candidate for 4,9
D3: 4,9 => CTR
* 873642915926.184735.1...826254193768369.85142187264539.18.2635.6358.129...2359681
D3: 3,7                                  # 20 pairs
E3: 4,9,1,2,3,7                          # reduction candidate for 4,9
E3: 4,9 => SOLVED
* 873642915926518473541397826254139768369785142187264539418926357635871294792453681
E3: 1,2,3,7                              # 18 pairs
* PAIR B3: 4,9 COL B
B9: 4,9,3                                # reduction candidate for 4,9
B9: 3 => CTR
* .736....5.26...47359....8.62541..768369.8.142.8.264539.18.2635.645831297.3245.681
B9: 4,9                                  # 19 pairs
* PAIR C3: 1,8 BLK 1
A1: 1,8,4,9                              # reduction candidate for 1,8
A1: 1,8                                  # 20 pairs
A2: 1,8,9                                # reduction candidate for 1,8
A2: 1,8                                  # 21 pairs
* PAIR D2: 5,9 BLK 2
F2: 5,9,8                                # reduction candidate for 5,9
F2: 5,9 => CTR
* 973642815826.1.473541..8926254193768369.8.142187264539.1892635.63587129..92.5.681
F2: 8                                    # 18 pairs
* PAIR E2: 1,9 BLK 2
E1: 1,9,2,4                              # reduction candidate for 1,9
E1: 1,9 => CTR
* 4736.8925826.1.47359....8.62541..768369.8.142.8.264539.18.2635.6.58.129...2.5.681
E1: 2,4                                  # 19 pairs
E3: 1,9,2,3,4,7                          # reduction candidate for 1,9
E3: 1,9 => SOLVED
* 873642915926518473541397826254139768369785142187264539418926357635871294792453681
E3: 2,3,4,7                              # 18 pairs
* PAIR E2: 1,9 ROW 2
A2: 1,9,8                                # reduction candidate for 1,9
A2: 8 => CTR
* 973642815826.1.473541..8926254193768369.8.142187264539.1892635.63587129..92.5.681
A2: 1,9                                  # 18 pairs
* PAIR G1: 8,9 ROW 1
A1: 8,9,1,4                              # reduction candidate for 8,9
A1: 8,9 => SOLVED
* 873642915926518473541397826254139768369785142187264539418926357635871294792453681
A1: 1,4                                  # 19 pairs
F1: 8,9,2                                # reduction candidate for 8,9
F1: 8,9                                  # 21 pairs
* PAIR H1: 1,2 ROW 1
E1: 1,2,4,9                              # reduction candidate for 1,2
E1: 1,2 => CTR
* 473618925.26...47359....8.62541..768369.8.142.8.264539.18.2635.6.58.129...2.5.681
E1: 4,9                                  # 19 pairs
* PAIR G3: 8,9 ROW 3
F3: 8,9,2,3,7                            # reduction candidate for 8,9
F3: 8,9 => CTR
* .73642.15.26.1.473541....262541..768369.8.142187264539.18.2635.635871294792453681
F3: 2,3,7                                # 18 pairs
* PAIR H3: 1,2 ROW 3
E3: 1,2,3,4,7,9                          # reduction candidate for 1,2
E3: 1,2 => CTR
* .7364.825.26..84735487239.62541..768369.8.142.81264539812..635.635871294497352681
E3: 3,4,7,9                              # 18 pairs
* PAIR E4: 3,9 COL E
E3: 3,9,1,2,4,7                          # reduction candidate for 3,9
E3: 3,9                                  # 23 pairs
E3: 1,2,4,7                              # 18 pairs
* PAIR F4: 3,9 COL F
F3: 3,9,2,7,8                            # reduction candidate for 3,9
F3: 3,9                                  # 25 pairs
F9: 3,9,2,7                              # reduction candidate for 3,9
F9: 3,9                                  # 21 pairs
* PAIR B8: 3,4 BLK 7
B9: 3,4,9                                # reduction candidate for 3,4
B9: 3,4 => CTR
* 4736.8925826.1.47359....8.62541..768369.8.142.8.264539.18.2635.6.58.129...2.5.681
B9: 9                                    # 21 pairs
* PAIR B8: 3,4 ROW 8
E8: 3,4,7                                # reduction candidate for 3,4
E8: 3,4                                  # 20 pairs
E8: 7                                    # 18 pairs
* PAIR C9: 2,7 BLK 7
C7: 2,7,8                                # reduction candidate for 2,7
C7: 2,7 => CTR
* .7364.8.5.265.8473548...9.62541..76836978514278126453981...635.6358.129.49..5.681
C7: 8                                    # 13 pairs
* PAIR C9: 2,7 ROW 9
F9: 2,7,3,9                              # reduction candidate for 2,7
F9: 2,7                                  # 22 pairs
F9: 3,9                                  # 21 pairs
* PAIR I7: 4,7 ROW 7
A7: 4,7,8,9                              # reduction candidate for 4,7
A7: 4,7                                  # 15 pairs
D7: 4,7,9                                # reduction candidate for 4,7
D7: 4,7                                  # 22 pairs
E7: 4,7,2,9                              # reduction candidate for 4,7
E7: 4,7 => CTR
* .736..8.5.265.84735487..9.62541..768369.8.1427812645398129.635.6.58.129..97352681
E7: 2,9                                  # 19 pairs
* PAIR I8: 4,7 ROW 8
E8: 4,7,3                                # reduction candidate for 4,7
E8: 3 => CTR
* .736....5.26...47359.347826254193768369785142.8.264539.18..635.6.5831297.3..5.681
E8: 4,7                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060611-absurd-base-pr-000.dot
* REASONING
* DIS # D3: 4,9 => CTR => D3: 3,7
* PRF # E3: 4,9 => SOL
* DIS # B9: 3 => CTR => B9: 4,9
* DIS # F2: 5,9 => CTR => F2: 8
* DIS # E1: 1,9 => CTR => E1: 2,4
* PRF # E3: 1,9 => SOL
* DIS # A2: 8 => CTR => A2: 1,9
* PRF # A1: 8,9 => SOL
* DIS # E1: 1,2 => CTR => E1: 4,9
* DIS # F3: 8,9 => CTR => F3: 2,3,7
* DIS # E3: 1,2 => CTR => E3: 3,4,7,9
* DIS # B9: 3,4 => CTR => B9: 9
* DIS # C7: 2,7 => CTR => C7: 8
* DIS # E7: 4,7 => CTR => E7: 2,9
* DIS # E8: 3 => CTR => E8: 4,7
* CNT  15 HDP CHAINS /  45 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,B3,B8,C3,C6,C9,D2,D5,E2,E4,F4,F5,G1,G3,H1,H3,I7,I8)
* .736....5.26...4735.......62541..768369.8.142.8.264539.1...635.6.58.129.....5.681
* PAIR B3: 4,9 BLK 1
A1: 4,9,1,8                              # reduction candidate for 4,9
A1: 4,9                                  # 21 pairs
A1: 1,8                                  # 20 pairs
* PAIR B3: 4,9 ROW 3
D3: 4,9,3,7                              # reduction candidate for 4,9
D3: 4,9 => CTR
* 873642915926.184735.1...826254193768369.85142187264539.18.2635.6358.129...2359681
E3: 4,9,1,2,3,7                          # reduction candidate for 4,9
E3: 4,9 => SOLVED
* 873642915926518473541397826254139768369785142187264539418926357635871294792453681
* DURATION: 0:00:03.919155  START: 23:46:54.250430  END: 23:46:58.169585 2019-04-30
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060611-absurd-base-pr-001.dot
* REASONING
* DIS # D3: 4,9 => CTR => D3: 3,7
* PRF D3: 3,7 # E3: 4,9 => SOL
* STA D3: 3,7 + E3: 4,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

Header Info

http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Jun&YEAR=2006, 20060611, absurd

Solution

position: 873642915926518473541397826254139768369785142187264539418926357635871294792453681 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 # A1: 4,9 => UNS
* INC # A1: 1,8 => UNS
* DIS # D3: 4,9 => CTR => D3: 3,7
* INC # D3: 3,7 => UNS
* PRF # E3: 4,9 => SOL
* INC # E3: 1,2,3,7 => UNS
* INC # B9: 4,9 => UNS
* DIS # B9: 3 => CTR => B9: 4,9
* INC # A1: 1,8 => UNS
* INC # A2: 1,8 => UNS
* DIS # F2: 5,9 => CTR => F2: 8
* INC # F2: 8 => UNS
* DIS # E1: 1,9 => CTR => E1: 2,4
* INC # E1: 2,4 => UNS
* PRF # E3: 1,9 => SOL
* INC # E3: 2,3,4,7 => UNS
* INC # A2: 1,9 => UNS
* DIS # A2: 8 => CTR => A2: 1,9
* PRF # A1: 8,9 => SOL
* INC # A1: 1,4 => UNS
* INC # F1: 8,9 => UNS
* DIS # E1: 1,2 => CTR => E1: 4,9
* INC # E1: 4,9 => UNS
* DIS # F3: 8,9 => CTR => F3: 2,3,7
* INC # F3: 2,3,7 => UNS
* DIS # E3: 1,2 => CTR => E3: 3,4,7,9
* INC # E3: 3,4,7,9 => UNS
* INC # E3: 3,9 => UNS
* INC # E3: 1,2,4,7 => UNS
* INC # F3: 3,9 => UNS
* INC # F9: 3,9 => UNS
* DIS # B9: 3,4 => CTR => B9: 9
* INC # B9: 9 => UNS
* INC # E8: 3,4 => UNS
* INC # E8: 7 => UNS
* DIS # C7: 2,7 => CTR => C7: 8
* INC # C7: 8 => UNS
* INC # F9: 2,7 => UNS
* INC # F9: 3,9 => UNS
* INC # A7: 4,7 => UNS
* INC # D7: 4,7 => UNS
* DIS # E7: 4,7 => CTR => E7: 2,9
* INC # E7: 2,9 => UNS
* INC # E8: 4,7 => UNS
* DIS # E8: 3 => CTR => E8: 4,7
* CNT  45 HDP CHAINS /  45 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A1: 4,9 => UNS
* INC # A1: 1,8 => UNS
* DIS # D3: 4,9 => CTR => D3: 3,7
* PRF D3: 3,7 # E3: 4,9 => SOL
* STA D3: 3,7 + E3: 4,9
* CNT   4 HDP CHAINS /   4 HYP OPENED