Analysis of zz-www.sudokuwiki.org-0011-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=11

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=11

position: 2....51.........64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...69....8 initial

Autosolve

position: 26...51...5.....64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...695...8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C2: 7,8 => CTR => C2: 1,3
* PRF # D1: 7,8 => SOL
* DIS # D1: 4 => CTR => D1: 7,8
* DIS # H1: 7,8 => CTR => H1: 3,9
* DIS # C5: 7,8 => CTR => C5: 1,2,3
* PRF # D8: 2,4 => SOL
* DIS # I7: 2,3 => CTR => I7: 6
* DIS # D7: 2,3 => CTR => D7: 1,4,6,8
* DIS # G8: 4,7 => CTR => G8: 6,9
* PRF # G8: 6,9 => SOL
* PRF # B9: 4,7 => SOL
* CNT  11 HDP CHAINS /  26 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 # C2: 7,8 => CTR => C2: 1,3
* PRF C2: 1,3 # D1: 7,8 => SOL
* STA C2: 1,3 + D1: 7,8
* CNT   2 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

2....51.........64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...69....8 initial
26...51...5.....64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...695...8 autosolve
267845193851239764394761852419682375723594681685317249942178536538426917176953428 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
C1: 7,8
E1: 4,9
H3: 2,5
I3: 2,5
E8: 2,4
H7: 2,3
G9: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I4,I5: 1.. / I4 = 1  =>  0 pairs (X) / I5 = 1  =>  7 pairs (_)
H3,I3: 2.. / H3 = 2  =>  0 pairs (X) / I3 = 2  =>  7 pairs (_)
H1,I1: 3.. / H1 = 3  =>  0 pairs (X) / I1 = 3  =>  8 pairs (_)
F9,H9: 3.. / F9 = 3  => 11 pairs (_) / H9 = 3  => 10 pairs (_)
C2,C5: 3.. / C2 = 3  => 12 pairs (_) / C5 = 3  => 14 pairs (_)
E2,E5: 3.. / E2 = 3  => 14 pairs (_) / E5 = 3  => 12 pairs (_)
I1,I7: 3.. / I1 = 3  =>  8 pairs (_) / I7 = 3  =>  0 pairs (X)
D1,E1: 4.. / D1 = 4  =>  0 pairs (X) / E1 = 4  =>  0 pairs (_)
H4,H6: 4.. / H4 = 4  =>  6 pairs (_) / H6 = 4  =>  0 pairs (*)
G8,G9: 4.. / G8 = 4  =>  0 pairs (X) / G9 = 4  =>  0 pairs (_)
E1,E8: 4.. / E1 = 4  =>  0 pairs (*) / E8 = 4  =>  0 pairs (X)
H3,I3: 5.. / H3 = 5  =>  7 pairs (_) / I3 = 5  =>  0 pairs (X)
H4,I4: 5.. / H4 = 5  =>  0 pairs (X) / I4 = 5  =>  7 pairs (_)
H3,H4: 5.. / H3 = 5  =>  7 pairs (_) / H4 = 5  =>  0 pairs (X)
I3,I4: 5.. / I3 = 5  =>  0 pairs (X) / I4 = 5  =>  7 pairs (_)
G5,G8: 6.. / G5 = 6  =>  8 pairs (_) / G8 = 6  =>  0 pairs (X)
E5,F6: 9.. / E5 = 9  =>  0 pairs (*) / F6 = 9  =>  0 pairs (X)
A7,B7: 9.. / A7 = 9  =>  8 pairs (_) / B7 = 9  =>  7 pairs (_)
G8,I8: 9.. / G8 = 9  =>  0 pairs (*) / I8 = 9  =>  0 pairs (X)
B3,B7: 9.. / B3 = 9  =>  8 pairs (_) / B7 = 9  =>  7 pairs (_)
* DURATION: 0:00:31.856766  START: 03:34:20.752357  END: 03:34:52.609123 2017-05-01
* CP COUNT: (20)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,E1,E8,G9,H3,H7,I3)
* 26...51...5.....64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...695...8
* PAIR C1: 7,8 BLK 1
A2: 7,8,1,3,9                            # reduction candidate for 7,8
A2: 7,8                                  # 11 pairs
C2: 7,8,1,3                              # reduction candidate for 7,8
C2: 7,8 => CTR
* 26...51...5.....64..4.6......9.8.3....35.4.....5.1.2....1.7.5..532.4..1...69514.8
C2: 1,3                                  #  8 pairs
A3: 7,8,1,3,9                            # reduction candidate for 7,8
A3: 7,8                                  # 15 pairs
B3: 7,8,1,9                              # reduction candidate for 7,8
B3: 7,8                                  #  9 pairs
* PAIR C1: 7,8 ROW 1
D1: 7,8,4                                # reduction candidate for 7,8
D1: 7,8 => SOLVED
* 267845193851239764394761852419682375723594681685317249942178536538426917176953428
D1: 4 => CTR
* 267495183.5.....64..4.6......9.8.3.....5.489...5.192......7.5..53..4..19..695.4.8
H1: 7,8,3,9                              # reduction candidate for 7,8
H1: 7,8 => CTR
* 267495183.5.....64..4.6......9.8.3.....5.489...5.1924.....7.5..53..4..19..695.4.8
H1: 3,9                                  #  8 pairs
* PAIR C1: 7,8 COL C
C5: 7,8,1,2,3                            # reduction candidate for 7,8
C5: 7,8 => CTR
* 26...51...53....64..4.6......9.8.3.....534...3.5.192....1.7.5..532.4..1...69514.8
C5: 1,2,3                                #  7 pairs
C8: 7,8,2                                # reduction candidate for 7,8
C8: 7,8                                  # 10 pairs
* PAIR E8: 2,4 BLK 8
D7: 2,4,1,3,6,8                          # reduction candidate for 2,4
D7: 2,4                                  # 15 pairs
D8: 2,4,6,8                              # reduction candidate for 2,4
D8: 2,4 => SOLVED
* 267845193851239764394761852419682375723594681685317249942178536538426917176953428
D8: 6,8                                  #  8 pairs
* PAIR H7: 2,3 BLK 9
I7: 2,3,6                                # reduction candidate for 2,3
I7: 2,3 => CTR
* 26...51...5.....64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...695...8
I7: 6                                    #  9 pairs
H9: 2,3,7                                # reduction candidate for 2,3
H9: 2,3                                  # 10 pairs
* PAIR H7: 2,3 ROW 7
D7: 2,3,1,4,6,8                          # reduction candidate for 2,3
D7: 2,3 => CTR
* 267845193.53.9..64..4.6...2..9.8.3.5..25.46.1..5.1.2.9...378526538426917726951438
D7: 1,4,6,8                              #  7 pairs
F7: 2,3,1,6,8                            # reduction candidate for 2,3
F7: 2,3                                  # 11 pairs
* PAIR G9: 4,7 BLK 9
G8: 4,7,6,9                              # reduction candidate for 4,7
G8: 4,7 => CTR
* 268495173.5.....64..4.6..52..9.8.345...5.4691.45.192874...7.5.653..4.719..695.4.8
G8: 6,9 => SOLVED
* 267845193851239764394761852419682375723594681685317249942178536538426917176953428
* PAIR G9: 4,7 ROW 9
A9: 4,7,1                                # reduction candidate for 4,7
A9: 4,7                                  # 12 pairs
B9: 4,7,1,2                              # reduction candidate for 4,7
B9: 4,7 => SOLVED
* 267845193851239764394761852419682375723594681685317249942178536538426917176953428
B9: 1,2                                  #  8 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0011-base-pr-000.dot
* REASONING
* DIS # C2: 7,8 => CTR => C2: 1,3
* PRF # D1: 7,8 => SOL
* DIS # D1: 4 => CTR => D1: 7,8
* DIS # H1: 7,8 => CTR => H1: 3,9
* DIS # C5: 7,8 => CTR => C5: 1,2,3
* PRF # D8: 2,4 => SOL
* DIS # I7: 2,3 => CTR => I7: 6
* DIS # D7: 2,3 => CTR => D7: 1,4,6,8
* DIS # G8: 4,7 => CTR => G8: 6,9
* PRF # G8: 6,9 => SOL
* PRF # B9: 4,7 => SOL
* CNT  11 HDP CHAINS /  26 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,E1,E8,G9,H3,H7,I3)
* 26...51...5.....64..4.6......9.8.3.....5.4.....5.1.2......7.5..53.....1...695...8
* PAIR C1: 7,8 BLK 1
A2: 7,8,1,3,9                            # reduction candidate for 7,8
A2: 7,8                                  # 11 pairs
C2: 7,8,1,3                              # reduction candidate for 7,8
C2: 7,8 => CTR
* 26...51...5.....64..4.6......9.8.3....35.4.....5.1.2....1.7.5..532.4..1...69514.8
A3: 7,8,1,3,9                            # reduction candidate for 7,8
A3: 7,8                                  # 15 pairs
B3: 7,8,1,9                              # reduction candidate for 7,8
B3: 7,8                                  #  9 pairs
* PAIR C1: 7,8 ROW 1
D1: 7,8,4                                # reduction candidate for 7,8
D1: 7,8 => SOLVED
* 267845193851239764394761852419682375723594681685317249942178536538426917176953428
* DURATION: 0:00:05.808494  START: 03:35:16.107568  END: 03:35:21.916062 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0011-base-pr-001.dot
* REASONING
* DIS # C2: 7,8 => CTR => C2: 1,3
* PRF C2: 1,3 # D1: 7,8 => SOL
* STA C2: 1,3 + D1: 7,8
* CNT   2 HDP CHAINS /   5 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=11

Solution

position: 267845193851239764394761852419682375723594681685317249942178536538426917176953428 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 # A2: 7,8 => UNS
* DIS # C2: 7,8 => CTR => C2: 1,3
* INC # C2: 1,3 => UNS
* INC # A3: 7,8 => UNS
* INC # B3: 7,8 => UNS
* PRF # D1: 7,8 => SOL
* DIS # D1: 4 => CTR => D1: 7,8
* DIS # H1: 7,8 => CTR => H1: 3,9
* INC # H1: 3,9 => UNS
* DIS # C5: 7,8 => CTR => C5: 1,2,3
* INC # C5: 1,2,3 => UNS
* INC # C8: 7,8 => UNS
* INC # D7: 2,4 => UNS
* PRF # D8: 2,4 => SOL
* INC # D8: 6,8 => UNS
* DIS # I7: 2,3 => CTR => I7: 6
* INC # I7: 6 => UNS
* INC # H9: 2,3 => UNS
* DIS # D7: 2,3 => CTR => D7: 1,4,6,8
* INC # D7: 1,4,6,8 => UNS
* INC # F7: 2,3 => UNS
* DIS # G8: 4,7 => CTR => G8: 6,9
* PRF # G8: 6,9 => SOL
* INC # A9: 4,7 => UNS
* PRF # B9: 4,7 => SOL
* INC # B9: 1,2 => UNS
* CNT  26 HDP CHAINS /  26 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A2: 7,8 => UNS
* DIS # C2: 7,8 => CTR => C2: 1,3
* INC C2: 1,3 # A3: 7,8 => UNS
* INC C2: 1,3 # B3: 7,8 => UNS
* PRF C2: 1,3 # D1: 7,8 => SOL
* STA C2: 1,3 + D1: 7,8
* CNT   5 HDP CHAINS /   5 HYP OPENED