Analysis of zz-www.sudokuoftheday.co.uk-20060625-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: ..3..9.........8.9..8........4....1.....73.8..3.14...539741.6..4...2..7...56....4 initial

Autosolve

position: ..3..9.........8.99.8........4....1.....7348.83.14.7.539741.6..4...2..7.2856.71.4 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # H1: 2,5 => SOL
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* DIS # G3: 2,5 => CTR => G3: 3
* PRF # G3: 3 => SOL
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* DIS # B4: 2,6 => CTR => B4: 5,7
* DIS # I4: 2,6 => CTR => I4: 3
* PRF # D4: 5,9 => SOL
* PRF # C6: 2,6 => SOL
* DIS # C6: 9 => CTR => C6: 2,6
* DIS # I4: 2,6 => CTR => I4: 3
* DIS # C5: 2,6 => CTR => C5: 1,9
* DIS # G4: 3 => CTR => G4: 2,9
* PRF # C6: 6 => SOL
* DIS # C5: 1,6 => CTR => C5: 2,9
* DIS # G8: 5 => CTR => G8: 3,9
* PRF # H1: 2,5 => SOL
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* DIS # G8: 5 => CTR => G8: 3,9
* CNT  20 HDP CHAINS /  53 HYP OPENED

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

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* PRF # H1: 2,5 => SOL
* STA H1: 2,5
* CNT   1 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

..3..9.........8.9..8........4....1.....73.8..3.14...539741.6..4...2..7...56....4 initial
..3..9.........8.99.8........4....1.....7348.83.14.7.539741.6..4...2..7.2856.71.4 autosolve
743869521652731849918254367574986213129573486836142795397418652461325978285697134 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (20)
F2: 1,4
F3: 1,4
G1: 2,5
I1: 1,7
I3: 1,7
F4: 2,6
D5: 5,9
F6: 2,6
I5: 2,6
H6: 2,9
B8: 1,6
C8: 1,6
F7: 5,8
D8: 3,9
F8: 5,8
E9: 3,9
H7: 2,5
I7: 2,8
I8: 3,8
H9: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F2,F3: 1.. / F2 = 1  => 19 pairs (_) / F3 = 1  => 16 pairs (_)
I1,I3: 1.. / I1 = 1  => 18 pairs (_) / I3 = 1  => 17 pairs (_)
B8,C8: 1.. / B8 = 1  => 20 pairs (_) / C8 = 1  => 19 pairs (_)
F4,F6: 2.. / F4 = 2  => 21 pairs (_) / F6 = 2  =>  0 pairs (*)
H7,I7: 2.. / H7 = 2  =>  0 pairs (X) / I7 = 2  => 18 pairs (_)
G4,I4: 3.. / G4 = 3  =>  0 pairs (X) / I4 = 3  => 18 pairs (_)
D8,E9: 3.. / D8 = 3  =>  0 pairs (*) / E9 = 3  =>  0 pairs (X)
E9,H9: 3.. / E9 = 3  =>  0 pairs (X) / H9 = 3  =>  0 pairs (_)
I4,I8: 3.. / I4 = 3  => 18 pairs (_) / I8 = 3  =>  0 pairs (X)
F2,F3: 4.. / F2 = 4  => 16 pairs (_) / F3 = 4  => 19 pairs (_)
B1,H1: 4.. / B1 = 4  => 20 pairs (_) / H1 = 4  => 20 pairs (_)
F7,F8: 5.. / F7 = 5  =>  0 pairs (X) / F8 = 5  => 18 pairs (_)
H7,G8: 5.. / H7 = 5  => 18 pairs (_) / G8 = 5  =>  0 pairs (X)
F7,H7: 5.. / F7 = 5  =>  0 pairs (X) / H7 = 5  => 18 pairs (_)
F8,G8: 5.. / F8 = 5  => 18 pairs (_) / G8 = 5  =>  0 pairs (X)
F4,F6: 6.. / F4 = 6  =>  0 pairs (*) / F6 = 6  =>  0 pairs (X)
I4,I5: 6.. / I4 = 6  =>  0 pairs (X) / I5 = 6  => 22 pairs (_)
B8,C8: 6.. / B8 = 6  => 19 pairs (_) / C8 = 6  => 20 pairs (_)
C6,F6: 6.. / C6 = 6  =>  0 pairs (*) / F6 = 6  =>  0 pairs (X)
I1,I3: 7.. / I1 = 7  => 17 pairs (_) / I3 = 7  => 18 pairs (_)
A4,B4: 7.. / A4 = 7  => 20 pairs (_) / B4 = 7  => 21 pairs (_)
D1,E1: 8.. / D1 = 8  =>  0 pairs (*) / E1 = 8  =>  0 pairs (X)
D4,E4: 8.. / D4 = 8  => 21 pairs (_) / E4 = 8  =>  0 pairs (*)
F7,F8: 8.. / F7 = 8  => 18 pairs (_) / F8 = 8  =>  0 pairs (X)
I7,I8: 8.. / I7 = 8  =>  0 pairs (X) / I8 = 8  => 18 pairs (_)
F7,I7: 8.. / F7 = 8  => 18 pairs (_) / I7 = 8  =>  0 pairs (X)
F8,I8: 8.. / F8 = 8  =>  0 pairs (X) / I8 = 8  => 18 pairs (_)
D1,D4: 8.. / D1 = 8  =>  0 pairs (*) / D4 = 8  =>  0 pairs (X)
E1,E4: 8.. / E1 = 8  => 21 pairs (_) / E4 = 8  =>  0 pairs (*)
C5,C6: 9.. / C5 = 9  =>  0 pairs (*) / C6 = 9  =>  0 pairs (X)
G4,H6: 9.. / G4 = 9  =>  0 pairs (X) / H6 = 9  =>  0 pairs (_)
D8,E9: 9.. / D8 = 9  =>  0 pairs (X) / E9 = 9  =>  0 pairs (_)
G8,H9: 9.. / G8 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
C5,D5: 9.. / C5 = 9  =>  0 pairs (*) / D5 = 9  =>  0 pairs (X)
C6,H6: 9.. / C6 = 9  =>  0 pairs (X) / H6 = 9  =>  0 pairs (_)
D8,G8: 9.. / D8 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
E9,H9: 9.. / E9 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
E4,E9: 9.. / E4 = 9  =>  0 pairs (X) / E9 = 9  =>  0 pairs (_)
G4,G8: 9.. / G4 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
H6,H9: 9.. / H6 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
* DURATION: 0:00:52.278030  START: 00:05:16.489673  END: 00:06:08.767703 2019-05-01
* CP COUNT: (40)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B8,C8,D5,D8,E9,F2,F3,F4,F6,F7,F8,G1,H6,H7,H9,I1,I3,I5,I7,I8)
* ..3..9.........8.99.8........4....1.....7348.83.14.7.539741.6..4...2..7.2856.71.4
* PAIR F2: 1,4 ROW 2
B2: 1,4,2,5,6,7                          # reduction candidate for 1,4
B2: 1,4                                  # 22 pairs
B2: 2,5,6,7                              # 20 pairs
* PAIR F3: 1,4 ROW 3
B3: 1,4,2,5,6,7                          # reduction candidate for 1,4
B3: 2,5,6,7                              # 20 pairs
B3: 1,4                                  # 19 pairs
* PAIR G1: 2,5 BLK 3
H1: 2,5,4,6                              # reduction candidate for 2,5
H1: 2,5 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
H1: 4,6                                  # 21 pairs
H2: 2,5,3,4,6                            # reduction candidate for 2,5
H2: 2,5 => CTR
* ..3..95......3.8299.8...3....498.213..957348683214679539741.6.24..32.978285697134
H2: 3,4,6                                # 20 pairs
G3: 2,5,3                                # reduction candidate for 2,5
G3: 2,5 => CTR
* ..3..9.........8.99.8........4.9..1...957348.83.14.72539741.6524..92537.285637194
G3: 3 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
H3: 2,5,3,4,6                            # reduction candidate for 2,5
H3: 2,5 => CTR
* ..386954...273.8.99.8...32...498.213..957348683.1427953974186524..325978285697134
H3: 3,4,6                                # 20 pairs
* PAIR G1: 2,5 ROW 1
B1: 2,5,1,4,6,7                          # reduction candidate for 2,5
B1: 2,5                                  # 23 pairs
D1: 2,5,7,8                              # reduction candidate for 2,5
D1: 2,5                                  # 23 pairs
* PAIR I1: 1,7 ROW 1
A1: 1,7,5,6                              # reduction candidate for 1,7
A1: 1,7                                  # 21 pairs
B1: 1,7,2,4,5,6                          # reduction candidate for 1,7
B1: 1,7                                  # 22 pairs
* PAIR I3: 1,7 ROW 3
B3: 1,7,2,4,5,6                          # reduction candidate for 1,7
B3: 2,4,5,6                              # 20 pairs
B3: 1,7                                  # 20 pairs
* PAIR F4: 2,6 ROW 4
B4: 2,6,5,7                              # reduction candidate for 2,6
B4: 2,6 => CTR
* ..3..9.........8.99.8......7.4....1....97348.83914672539741.6524..32597.2856.71.4
B4: 5,7                                  # 21 pairs
I4: 2,6,3                                # reduction candidate for 2,6
I4: 2,6 => CTR
* ..3..9.........8.99.8........4...31.....7348.83.14.79539741.6..4...2.9732856.71.4
I4: 3                                    # 18 pairs
* PAIR D5: 5,9 BLK 5
D4: 5,9,8                                # reduction candidate for 5,9
D4: 5,9 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
D4: 8                                    # 21 pairs
E4: 5,9,8                                # reduction candidate for 5,9
E4: 5,9                                  # 21 pairs
* PAIR F6: 2,6 ROW 6
C6: 2,6,9                                # reduction candidate for 2,6
C6: 2,6 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
C6: 9 => CTR
* ..3..9.........8.99.8........4.9231.....7348.83914672539741.6524...25.782856.7194
* PAIR I5: 2,6 BLK 6
I4: 2,6,3                                # reduction candidate for 2,6
I4: 2,6 => CTR
* ..3..9.........8.99.8........4...31.....7348.83.14.79539741.6..4...2.9732856.71.4
I4: 3                                    # 18 pairs
* PAIR I5: 2,6 ROW 5
B5: 2,6,1,5                              # reduction candidate for 2,6
B5: 2,6                                  # 23 pairs
C5: 2,6,1,9                              # reduction candidate for 2,6
C5: 2,6 => CTR
* ..3..9.........8.99.8........4....1....97348.83914672539741.6524..32597.2856.71.4
C5: 1,9                                  # 21 pairs
* PAIR H6: 2,9 BLK 6
G4: 2,9,3                                # reduction candidate for 2,9
G4: 3 => CTR
* ..3..9.........8.99.8........4...31.....7348.83.14.79539741.6..4...2.9732856.71.4
G4: 2,9                                  # 18 pairs
* PAIR H6: 2,9 ROW 6
C6: 2,9,6                                # reduction candidate for 2,9
C6: 6 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
C6: 2,9                                  # 21 pairs
* PAIR B8: 1,6 COL B
B1: 1,6,2,4,5,7                          # reduction candidate for 1,6
B1: 1,6                                  # 22 pairs
B2: 1,6,2,4,5,7                          # reduction candidate for 1,6
B2: 1,6                                  # 22 pairs
B3: 1,6,2,4,5,7                          # reduction candidate for 1,6
B3: 1,6                                  # 22 pairs
B5: 1,6,2,5                              # reduction candidate for 1,6
B5: 1,6                                  # 21 pairs
* PAIR C8: 1,6 COL C
C2: 1,6,2                                # reduction candidate for 1,6
C2: 1,6                                  # 23 pairs
C5: 1,6,2,9                              # reduction candidate for 1,6
C5: 1,6 => CTR
* ..3..9.........8.99.8........4....1....97348.83914672539741.6524..32597.2856.71.4
C5: 2,9                                  # 21 pairs
* PAIR D8: 3,9 ROW 8
G8: 3,9,5                                # reduction candidate for 3,9
G8: 5 => CTR
* ..3..9.........8.99.8........4...913...97348.83.14.7.539741.6..4...2..7.2856.71.4
G8: 3,9                                  # 18 pairs
* PAIR H7: 2,5 COL H
H1: 2,5,4,6                              # reduction candidate for 2,5
H1: 2,5 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
H1: 4,6                                  # 21 pairs
H2: 2,5,3,4,6                            # reduction candidate for 2,5
H2: 2,5 => CTR
* ..3..95......3.8299.8...3....498.213..957348683214679539741.6.24..32.978285697134
H2: 3,4,6                                # 20 pairs
H3: 2,5,3,4,6                            # reduction candidate for 2,5
H3: 2,5 => CTR
* ..386954...273.8.99.8...32...498.213..957348683.1427953974186524..325978285697134
H3: 3,4,6                                # 20 pairs
* PAIR H9: 3,9 BLK 9
G8: 3,9,5                                # reduction candidate for 3,9
G8: 5 => CTR
* ..3..9.........8.99.8........4...913...97348.83.14.7.539741.6..4...2..7.2856.71.4
G8: 3,9                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060625-absurd-base-pr-000.dot
* REASONING
* PRF # H1: 2,5 => SOL
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* DIS # G3: 2,5 => CTR => G3: 3
* PRF # G3: 3 => SOL
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* DIS # B4: 2,6 => CTR => B4: 5,7
* DIS # I4: 2,6 => CTR => I4: 3
* PRF # D4: 5,9 => SOL
* PRF # C6: 2,6 => SOL
* DIS # C6: 9 => CTR => C6: 2,6
* DIS # I4: 2,6 => CTR => I4: 3
* DIS # C5: 2,6 => CTR => C5: 1,9
* DIS # G4: 3 => CTR => G4: 2,9
* PRF # C6: 6 => SOL
* DIS # C5: 1,6 => CTR => C5: 2,9
* DIS # G8: 5 => CTR => G8: 3,9
* PRF # H1: 2,5 => SOL
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* DIS # G8: 5 => CTR => G8: 3,9
* CNT  20 HDP CHAINS /  53 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B8,C8,D5,D8,E9,F2,F3,F4,F6,F7,F8,G1,H6,H7,H9,I1,I3,I5,I7,I8)
* ..3..9.........8.99.8........4....1.....7348.83.14.7.539741.6..4...2..7.2856.71.4
* PAIR F2: 1,4 ROW 2
B2: 1,4,2,5,6,7                          # reduction candidate for 1,4
B2: 1,4                                  # 22 pairs
B2: 2,5,6,7                              # 20 pairs
* PAIR F3: 1,4 ROW 3
B3: 1,4,2,5,6,7                          # reduction candidate for 1,4
B3: 2,5,6,7                              # 20 pairs
B3: 1,4                                  # 19 pairs
* PAIR G1: 2,5 BLK 3
H1: 2,5,4,6                              # reduction candidate for 2,5
H1: 2,5 => SOLVED
* 743869521652731849918254367574986213129573486836142795397418652461325978285697134
* DURATION: 0:00:04.380317  START: 00:06:46.043541  END: 00:06:50.423858 2019-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060625-absurd-base-pr-001.dot
* REASONING
* PRF # H1: 2,5 => SOL
* STA H1: 2,5
* CNT   1 HDP CHAINS /   5 HYP OPENED

Header Info

http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Jun&YEAR=2006, 20060625, absurd

Solution

position: 743869521652731849918254367574986213129573486836142795397418652461325978285697134 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 # B2: 1,4 => UNS
* INC # B2: 2,5,6,7 => UNS
* INC # B3: 1,4 => UNS
* INC # B3: 2,5,6,7 => UNS
* PRF # H1: 2,5 => SOL
* INC # H1: 4,6 => UNS
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* INC # H2: 3,4,6 => UNS
* DIS # G3: 2,5 => CTR => G3: 3
* PRF # G3: 3 => SOL
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* INC # H3: 3,4,6 => UNS
* INC # B1: 2,5 => UNS
* INC # D1: 2,5 => UNS
* INC # A1: 1,7 => UNS
* INC # B1: 1,7 => UNS
* INC # B3: 1,7 => UNS
* INC # B3: 2,4,5,6 => UNS
* DIS # B4: 2,6 => CTR => B4: 5,7
* INC # B4: 5,7 => UNS
* DIS # I4: 2,6 => CTR => I4: 3
* INC # I4: 3 => UNS
* PRF # D4: 5,9 => SOL
* INC # D4: 8 => UNS
* INC # E4: 5,9 => UNS
* PRF # C6: 2,6 => SOL
* DIS # C6: 9 => CTR => C6: 2,6
* DIS # I4: 2,6 => CTR => I4: 3
* INC # I4: 3 => UNS
* INC # B5: 2,6 => UNS
* DIS # C5: 2,6 => CTR => C5: 1,9
* INC # C5: 1,9 => UNS
* INC # G4: 2,9 => UNS
* DIS # G4: 3 => CTR => G4: 2,9
* INC # C6: 2,9 => UNS
* PRF # C6: 6 => SOL
* INC # B1: 1,6 => UNS
* INC # B2: 1,6 => UNS
* INC # B3: 1,6 => UNS
* INC # B5: 1,6 => UNS
* INC # C2: 1,6 => UNS
* DIS # C5: 1,6 => CTR => C5: 2,9
* INC # C5: 2,9 => UNS
* INC # G8: 3,9 => UNS
* DIS # G8: 5 => CTR => G8: 3,9
* PRF # H1: 2,5 => SOL
* INC # H1: 4,6 => UNS
* DIS # H2: 2,5 => CTR => H2: 3,4,6
* INC # H2: 3,4,6 => UNS
* DIS # H3: 2,5 => CTR => H3: 3,4,6
* INC # H3: 3,4,6 => UNS
* INC # G8: 3,9 => UNS
* DIS # G8: 5 => CTR => G8: 3,9
* CNT  53 HDP CHAINS /  53 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B2: 1,4 => UNS
* INC # B2: 2,5,6,7 => UNS
* INC # B3: 1,4 => UNS
* INC # B3: 2,5,6,7 => UNS
* PRF # H1: 2,5 => SOL
* STA H1: 2,5
* CNT   5 HDP CHAINS /   5 HYP OPENED