Analysis of zz-www.sudokuoftheday.co.uk-20060508-absurd-base.sdk

Contents

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

level: medium

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

position: .1.....5.8...67.....34..8..5.82...969..78.5....1..5.8.1......37.8....9...37...... initial

Autosolve

position: 71....65.8...67.....34..87.5.82...969..78.5..3.1..5.8.1......37.8..7.9.5.37.....8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I5: 2,4 => CTR => I5: 1,3
* DIS # C5: 4 => CTR => C5: 2,6
* PRF # E9: 2,4 => SOL
* DIS # H9: 2,4 => CTR => H9: 1,6
* DIS # G2: 2,4 => CTR => G2: 1,3
* CNT   5 HDP CHAINS /  43 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 # I5: 2,4 => CTR => I5: 1,3
* DIS I5: 1,3 # C5: 4 => CTR => C5: 2,6
* DIS I5: 1,3 + C5: 2,6 # F8: 2,4 => CTR => F8: 1,3
* PRF I5: 1,3 + C5: 2,6 + F8: 1,3 # E9: 2,4 => SOL
* STA I5: 1,3 + C5: 2,6 + F8: 1,3 + E9: 2,4
* CNT   4 HDP CHAINS /  39 HYP OPENED

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

Details

Positions

.1.....5.8...67.....34..8..5.82...969..78.5....1..5.8.1......37.8....9...37...... initial
71....65.8...67.....34..87.5.82...969..78.5..3.1..5.8.1......37.8..7.9.5.37.....8 autosolve
714938652825167349693452871548213796962784513371695284159826437486371925237549168 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
A3: 2,6
B4: 4,7
D6: 6,9
E6: 4,9
I6: 2,4
B7: 5,9
C7: 5,9
C8: 2,6
D7: 6,8
E7: 2,4
F7: 6,8
D8: 1,3
G7: 2,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E7,G7: 2.. / E7 = 2  => 14 pairs (_) / G7 = 2  => 12 pairs (_)
G4,I5: 3.. / G4 = 3  => 18 pairs (_) / I5 = 3  => 14 pairs (_)
D8,F8: 3.. / D8 = 3  => 15 pairs (_) / F8 = 3  =>  0 pairs (X)
F5,I5: 3.. / F5 = 3  => 18 pairs (_) / I5 = 3  => 14 pairs (_)
E1,E4: 3.. / E1 = 3  => 16 pairs (_) / E4 = 3  => 22 pairs (_)
G2,G4: 3.. / G2 = 3  => 14 pairs (_) / G4 = 3  => 18 pairs (_)
A8,A9: 4.. / A8 = 4  => 14 pairs (_) / A9 = 4  => 17 pairs (_)
C1,I1: 4.. / C1 = 4  => 15 pairs (_) / I1 = 4  => 18 pairs (_)
E7,G7: 4.. / E7 = 4  => 12 pairs (_) / G7 = 4  => 14 pairs (_)
D2,E3: 5.. / D2 = 5  => 18 pairs (_) / E3 = 5  => 13 pairs (_)
B7,C7: 5.. / B7 = 5  => 12 pairs (_) / C7 = 5  => 11 pairs (_)
D9,E9: 5.. / D9 = 5  => 13 pairs (_) / E9 = 5  => 18 pairs (_)
B3,E3: 5.. / B3 = 5  => 18 pairs (_) / E3 = 5  => 13 pairs (_)
C2,C7: 5.. / C2 = 5  => 12 pairs (_) / C7 = 5  => 11 pairs (_)
D2,D9: 5.. / D2 = 5  => 18 pairs (_) / D9 = 5  => 13 pairs (_)
E3,E9: 5.. / E3 = 5  => 13 pairs (_) / E9 = 5  => 18 pairs (_)
A3,B3: 6.. / A3 = 6  => 14 pairs (_) / B3 = 6  =>  0 pairs (X)
F5,D6: 6.. / F5 = 6  =>  0 pairs (X) / D6 = 6  => 11 pairs (_)
D7,F7: 6.. / D7 = 6  =>  0 pairs (X) / F7 = 6  => 11 pairs (_)
H8,H9: 6.. / H8 = 6  =>  0 pairs (X) / H9 = 6  => 14 pairs (_)
B6,D6: 6.. / B6 = 6  =>  0 pairs (X) / D6 = 6  => 11 pairs (_)
A9,H9: 6.. / A9 = 6  =>  0 pairs (X) / H9 = 6  => 14 pairs (_)
C5,C8: 6.. / C5 = 6  =>  0 pairs (X) / C8 = 6  => 14 pairs (_)
D6,D7: 6.. / D6 = 6  => 11 pairs (_) / D7 = 6  =>  0 pairs (X)
F5,F7: 6.. / F5 = 6  =>  0 pairs (X) / F7 = 6  => 11 pairs (_)
B4,B6: 7.. / B4 = 7  => 12 pairs (_) / B6 = 7  => 23 pairs (_)
G4,G6: 7.. / G4 = 7  => 23 pairs (_) / G6 = 7  => 12 pairs (_)
B4,G4: 7.. / B4 = 7  => 12 pairs (_) / G4 = 7  => 23 pairs (_)
B6,G6: 7.. / B6 = 7  => 23 pairs (_) / G6 = 7  => 12 pairs (_)
D1,F1: 8.. / D1 = 8  =>  0 pairs (X) / F1 = 8  => 11 pairs (_)
D7,F7: 8.. / D7 = 8  => 11 pairs (_) / F7 = 8  =>  0 pairs (X)
D1,D7: 8.. / D1 = 8  =>  0 pairs (X) / D7 = 8  => 11 pairs (_)
F1,F7: 8.. / F1 = 8  => 11 pairs (_) / F7 = 8  =>  0 pairs (X)
D6,E6: 9.. / D6 = 9  =>  0 pairs (X) / E6 = 9  => 11 pairs (_)
B7,C7: 9.. / B7 = 9  => 11 pairs (_) / C7 = 9  => 12 pairs (_)
* DURATION: 0:00:39.402386  START: 22:59:47.519710  END: 23:00:26.922096 2019-04-30
* CP COUNT: (35)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B4,B7,C7,C8,D6,D7,D8,E6,E7,F7,G7,I6)
* 71....65.8...67.....34..87.5.82...969..78.5..3.1..5.8.1......37.8..7.9.5.37.....8
* PAIR A3: 2,6 BLK 1
B3: 2,6,5,9                              # reduction candidate for 2,6
B3: 2,6                                  # 19 pairs
B3: 5,9                                  # 16 pairs
* PAIR A3: 2,6 COL A
A8: 2,6,4                                # reduction candidate for 2,6
A8: 2,6                                  # 17 pairs
A9: 2,6,4                                # reduction candidate for 2,6
A9: 2,6                                  # 14 pairs
* PAIR B4: 4,7 BLK 4
B6: 4,7,2,6                              # reduction candidate for 4,7
B6: 4,7                                  # 16 pairs
B6: 2,6                                  # 14 pairs
* PAIR B4: 4,7 ROW 4
G4: 4,7,1,3                              # reduction candidate for 4,7
G4: 4,7                                  # 23 pairs
G4: 1,3                                  # 13 pairs
* PAIR E6: 4,9 COL E
E9: 4,9,1,2,5                            # reduction candidate for 4,9
E9: 4,9                                  # 24 pairs
E9: 1,2,5                                # 13 pairs
* PAIR I6: 2,4 BLK 6
H5: 2,4,1                                # reduction candidate for 2,4
H5: 2,4                                  # 15 pairs
I5: 2,4,1,3                              # reduction candidate for 2,4
I5: 2,4 => CTR
* 71.93865.8..167..3..345.87.5.82..3969..78351.3.169578.1..8.6.37.8.3719.5.37...1.8
I5: 1,3                                  # 14 pairs
G6: 2,4,7                                # reduction candidate for 2,4
G6: 2,4                                  # 23 pairs
* PAIR I6: 2,4 ROW 6
B6: 2,4,6,7                              # reduction candidate for 2,4
B6: 6,7                                  # 15 pairs
B6: 2,4                                  # 11 pairs
* PAIR I6: 2,4 COL I
I1: 2,4,3,9                              # reduction candidate for 2,4
I1: 2,4                                  # 16 pairs
I2: 2,4,1,3,9                            # reduction candidate for 2,4
I2: 2,4                                  # 24 pairs
* PAIR B7: 5,9 COL B
B2: 5,9,2,4                              # reduction candidate for 5,9
B2: 5,9                                  # 19 pairs
B3: 5,9,2,6                              # reduction candidate for 5,9
B3: 5,9                                  # 16 pairs
* PAIR C7: 5,9 COL C
C2: 5,9,2,4                              # reduction candidate for 5,9
C2: 2,4                                  # 21 pairs
C2: 5,9                                  # 15 pairs
* PAIR C8: 2,6 BLK 7
A8: 2,6,4                                # reduction candidate for 2,6
A8: 2,6                                  # 17 pairs
A9: 2,6,4                                # reduction candidate for 2,6
A9: 2,6                                  # 14 pairs
* PAIR C8: 2,6 ROW 8
H8: 2,6,1,4                              # reduction candidate for 2,6
H8: 2,6                                  # 17 pairs
H8: 1,4                                  # 16 pairs
* PAIR C8: 2,6 COL C
C5: 2,6,4                                # reduction candidate for 2,6
C5: 4 => CTR
* 71....65484..67.2.6.34..87.5782.43969.478.5..3.1..57821......37.86.7.945437...168
C5: 2,6                                  # 15 pairs
* PAIR E7: 2,4 BLK 8
F8: 2,4,1,3                              # reduction candidate for 2,4
F8: 2,4                                  # 28 pairs
E9: 2,4,1,5,9                            # reduction candidate for 2,4
E9: 2,4 => SOLVED
* 714938652825167349693452871548213796962784513371695284159826437486371925237549168
E9: 1,5,9                                # 13 pairs
F9: 2,4,1,9                              # reduction candidate for 2,4
F9: 2,4                                  # 19 pairs
* PAIR D8: 1,3 BLK 8
F8: 1,3,2,4                              # reduction candidate for 1,3
F8: 2,4                                  # 28 pairs
F8: 1,3                                  # 15 pairs
* PAIR D8: 1,3 COL D
D2: 1,3,5,9                              # reduction candidate for 1,3
D2: 5,9                                  # 17 pairs
D2: 1,3                                  # 15 pairs
* PAIR G7: 2,4 BLK 9
H8: 2,4,1,6                              # reduction candidate for 2,4
H8: 2,4                                  # 17 pairs
G9: 2,4,1                                # reduction candidate for 2,4
G9: 2,4                                  # 20 pairs
H9: 2,4,1,6                              # reduction candidate for 2,4
H9: 2,4 => CTR
* 71....65.8...67...26345.87.5.821..969.678.5..3.1695.8.1..8.6.37482.7.9656375.91.8
H9: 1,6                                  # 14 pairs
* PAIR G7: 2,4 COL G
G2: 2,4,1,3                              # reduction candidate for 2,4
G2: 2,4 => CTR
* 71.93865.8..167..3..345.87.5.82..3969..7835..3.169578.1..8.6.37.8.37.9.5.37...1.8
G2: 1,3                                  # 14 pairs
G6: 2,4,7                                # reduction candidate for 2,4
G6: 2,4                                  # 23 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060508-absurd-base-pr-000.dot
* REASONING
* DIS # I5: 2,4 => CTR => I5: 1,3
* DIS # C5: 4 => CTR => C5: 2,6
* PRF # E9: 2,4 => SOL
* DIS # H9: 2,4 => CTR => H9: 1,6
* DIS # G2: 2,4 => CTR => G2: 1,3
* CNT   5 HDP CHAINS /  43 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B4,B7,C7,C8,D6,D7,D8,E6,E7,F7,G7,I6)
* 71....65.8...67.....34..87.5.82...969..78.5..3.1..5.8.1......37.8..7.9.5.37.....8
* PAIR A3: 2,6 BLK 1
B3: 2,6,5,9                              # reduction candidate for 2,6
B3: 2,6                                  # 19 pairs
B3: 5,9                                  # 16 pairs
* PAIR A3: 2,6 COL A
A8: 2,6,4                                # reduction candidate for 2,6
A8: 2,6                                  # 17 pairs
A9: 2,6,4                                # reduction candidate for 2,6
A9: 2,6                                  # 14 pairs
* PAIR B4: 4,7 BLK 4
B6: 4,7,2,6                              # reduction candidate for 4,7
B6: 4,7                                  # 16 pairs
B6: 2,6                                  # 14 pairs
* PAIR B4: 4,7 ROW 4
G4: 4,7,1,3                              # reduction candidate for 4,7
G4: 4,7                                  # 23 pairs
G4: 1,3                                  # 13 pairs
* PAIR E6: 4,9 COL E
E9: 4,9,1,2,5                            # reduction candidate for 4,9
E9: 4,9                                  # 24 pairs
E9: 1,2,5                                # 13 pairs
* PAIR I6: 2,4 BLK 6
H5: 2,4,1                                # reduction candidate for 2,4
H5: 2,4                                  # 15 pairs
I5: 2,4,1,3                              # reduction candidate for 2,4
I5: 2,4 => CTR
* 71.93865.8..167..3..345.87.5.82..3969..78351.3.169578.1..8.6.37.8.3719.5.37...1.8
G6: 2,4,7                                # reduction candidate for 2,4
G6: 2,4                                  # 23 pairs
* PAIR I6: 2,4 ROW 6
B6: 2,4,6,7                              # reduction candidate for 2,4
B6: 6,7                                  # 16 pairs
B6: 2,4                                  # 12 pairs
* PAIR I6: 2,4 COL I
I1: 2,4,3,9                              # reduction candidate for 2,4
I1: 2,4                                  # 16 pairs
I2: 2,4,1,3,9                            # reduction candidate for 2,4
I2: 2,4                                  # 24 pairs
* PAIR RESTART
* PAIR I6: 2,4 BLK 6
H5: 2,4,1                                # reduction candidate for 2,4
H5: 2,4                                  # 15 pairs
G6: 2,4,7                                # reduction candidate for 2,4
G6: 2,4                                  # 23 pairs
* PAIR I6: 2,4 ROW 6
B6: 2,4,6,7                              # reduction candidate for 2,4
B6: 6,7                                  # 16 pairs
B6: 2,4                                  # 12 pairs
* PAIR I6: 2,4 COL I
I1: 2,4,3,9                              # reduction candidate for 2,4
I1: 2,4                                  # 16 pairs
I2: 2,4,1,3,9                            # reduction candidate for 2,4
I2: 2,4                                  # 24 pairs
* PAIR B7: 5,9 COL B
B2: 5,9,2,4                              # reduction candidate for 5,9
B2: 5,9                                  # 20 pairs
B3: 5,9,2,6                              # reduction candidate for 5,9
B3: 5,9                                  # 17 pairs
* PAIR C7: 5,9 COL C
C2: 5,9,2,4                              # reduction candidate for 5,9
C2: 2,4                                  # 21 pairs
C2: 5,9                                  # 16 pairs
* PAIR C8: 2,6 BLK 7
A8: 2,6,4                                # reduction candidate for 2,6
A8: 2,6                                  # 18 pairs
A9: 2,6,4                                # reduction candidate for 2,6
A9: 2,6                                  # 15 pairs
* PAIR C8: 2,6 ROW 8
H8: 2,6,1,4                              # reduction candidate for 2,6
H8: 2,6                                  # 18 pairs
H8: 1,4                                  # 17 pairs
* PAIR C8: 2,6 COL C
C5: 2,6,4                                # reduction candidate for 2,6
C5: 4 => CTR
* 71....65484..67.2.6.34..87.5782.43969.478.5..3.1..57821......37.86.7.945437...168
* PAIR RESTART
* PAIR C8: 2,6 BLK 7
A8: 2,6,4                                # reduction candidate for 2,6
A8: 2,6                                  # 20 pairs
A9: 2,6,4                                # reduction candidate for 2,6
A9: 2,6                                  # 17 pairs
* PAIR C8: 2,6 ROW 8
H8: 2,6,1,4                              # reduction candidate for 2,6
H8: 2,6                                  # 20 pairs
H8: 1,4                                  # 19 pairs
* PAIR E7: 2,4 BLK 8
F8: 2,4,1,3                              # reduction candidate for 2,4
F8: 2,4 => CTR
* 71493865282..67.4.6.34..87.5782...969..78.5..3.169578.1..8.6.37.8.37.915.37..9.68
E9: 2,4,5,9                              # reduction candidate for 2,4
E9: 2,4 => SOLVED
* 714938652825167349693452871548213796962784513371695284159826437486371925237549168
* DURATION: 0:00:25.013795  START: 23:00:54.047387  END: 23:01:19.061182 2019-04-30
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060508-absurd-base-pr-001.dot
* REASONING
* DIS # I5: 2,4 => CTR => I5: 1,3
* DIS I5: 1,3 # C5: 4 => CTR => C5: 2,6
* DIS I5: 1,3 + C5: 2,6 # F8: 2,4 => CTR => F8: 1,3
* PRF I5: 1,3 + C5: 2,6 + F8: 1,3 # E9: 2,4 => SOL
* STA I5: 1,3 + C5: 2,6 + F8: 1,3 + E9: 2,4
* CNT   4 HDP CHAINS /  39 HYP OPENED

Header Info

http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=May&YEAR=2006, 20060508, absurd

Solution

position: 714938652825167349693452871548213796962784513371695284159826437486371925237549168 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 # B3: 2,6 => UNS
* INC # B3: 5,9 => UNS
* INC # A8: 2,6 => UNS
* INC # A9: 2,6 => UNS
* INC # B6: 4,7 => UNS
* INC # B6: 2,6 => UNS
* INC # G4: 4,7 => UNS
* INC # G4: 1,3 => UNS
* INC # E9: 4,9 => UNS
* INC # E9: 1,2,5 => UNS
* INC # H5: 2,4 => UNS
* DIS # I5: 2,4 => CTR => I5: 1,3
* INC # I5: 1,3 => UNS
* INC # G6: 2,4 => UNS
* INC # B6: 2,4 => UNS
* INC # B6: 6,7 => UNS
* INC # I1: 2,4 => UNS
* INC # I2: 2,4 => UNS
* INC # B2: 5,9 => UNS
* INC # B3: 5,9 => UNS
* INC # C2: 5,9 => UNS
* INC # C2: 2,4 => UNS
* INC # A8: 2,6 => UNS
* INC # A9: 2,6 => UNS
* INC # H8: 2,6 => UNS
* INC # H8: 1,4 => UNS
* INC # C5: 2,6 => UNS
* DIS # C5: 4 => CTR => C5: 2,6
* INC # F8: 2,4 => UNS
* PRF # E9: 2,4 => SOL
* INC # E9: 1,5,9 => UNS
* INC # F9: 2,4 => UNS
* INC # F8: 1,3 => UNS
* INC # F8: 2,4 => UNS
* INC # D2: 1,3 => UNS
* INC # D2: 5,9 => UNS
* INC # H8: 2,4 => UNS
* INC # G9: 2,4 => UNS
* DIS # H9: 2,4 => CTR => H9: 1,6
* INC # H9: 1,6 => UNS
* DIS # G2: 2,4 => CTR => G2: 1,3
* INC # G2: 1,3 => UNS
* INC # G6: 2,4 => UNS
* CNT  43 HDP CHAINS /  43 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 2,6 => UNS
* INC # B3: 5,9 => UNS
* INC # A8: 2,6 => UNS
* INC # A9: 2,6 => UNS
* INC # B6: 4,7 => UNS
* INC # B6: 2,6 => UNS
* INC # G4: 4,7 => UNS
* INC # G4: 1,3 => UNS
* INC # E9: 4,9 => UNS
* INC # E9: 1,2,5 => UNS
* INC # H5: 2,4 => UNS
* DIS # I5: 2,4 => CTR => I5: 1,3
* INC I5: 1,3 # G6: 2,4 => UNS
* INC I5: 1,3 # B6: 2,4 => UNS
* INC I5: 1,3 # B6: 6,7 => UNS
* INC I5: 1,3 # I1: 2,4 => UNS
* INC I5: 1,3 # I2: 2,4 => UNS
* INC I5: 1,3 # H5: 2,4 => UNS
* INC I5: 1,3 # G6: 2,4 => UNS
* INC I5: 1,3 # B6: 2,4 => UNS
* INC I5: 1,3 # B6: 6,7 => UNS
* INC I5: 1,3 # I1: 2,4 => UNS
* INC I5: 1,3 # I2: 2,4 => UNS
* INC I5: 1,3 # B2: 5,9 => UNS
* INC I5: 1,3 # B3: 5,9 => UNS
* INC I5: 1,3 # C2: 5,9 => UNS
* INC I5: 1,3 # C2: 2,4 => UNS
* INC I5: 1,3 # A8: 2,6 => UNS
* INC I5: 1,3 # A9: 2,6 => UNS
* INC I5: 1,3 # H8: 2,6 => UNS
* INC I5: 1,3 # H8: 1,4 => UNS
* INC I5: 1,3 # C5: 2,6 => UNS
* DIS I5: 1,3 # C5: 4 => CTR => C5: 2,6
* INC I5: 1,3 + C5: 2,6 # A8: 2,6 => UNS
* INC I5: 1,3 + C5: 2,6 # A9: 2,6 => UNS
* INC I5: 1,3 + C5: 2,6 # H8: 2,6 => UNS
* INC I5: 1,3 + C5: 2,6 # H8: 1,4 => UNS
* DIS I5: 1,3 + C5: 2,6 # F8: 2,4 => CTR => F8: 1,3
* PRF I5: 1,3 + C5: 2,6 + F8: 1,3 # E9: 2,4 => SOL
* STA I5: 1,3 + C5: 2,6 + F8: 1,3 + E9: 2,4
* CNT  39 HDP CHAINS /  39 HYP OPENED