Analysis of zz-www.sudokuwiki.org-0100-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=100

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=100

position: .7.......5.....17...4..8..9...4..29....8.6....96..7...1..3..4...28.....5.......2. initial

Autosolve

position: .7.......5.....17...4..8..9...4..296...896....96..7...1..3..4...28.....5.......2. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A5: 3,4 => CTR => A5: 2
* DIS # A9: 3,4 => CTR => A9: 6,7,9
* DIS # B9: 5,6 => CTR => B9: 3,4
* DIS # E7: 6,8 => CTR => E7: 2,5,7
* DIS # I9: 7,8 => CTR => I9: 1,3
* DIS # E7: 7,8 => CTR => E7: 2,5,6
* CNT   6 HDP CHAINS /  23 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 # A5: 3,4 => CTR => A5: 2
* DIS A5: 2 # B5: 5 => CTR => B5: 3,4
* PRF A5: 2 + B5: 3,4 # I6: 3,4 => SOL
* STA A5: 2 + B5: 3,4 + I6: 3,4
* CNT   3 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

.7.......5.....17...4..8..9...4..29....8.6....96..7...1..3..4...28.....5.......2. initial
.7.......5.....17...4..8..9...4..296...896....96..7...1..3..4...28.....5.......2. autosolve
972135648583964172614278539857413296231896754496527813169352487328741965745689321 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
A6: 3,4
B7: 5,6
H7: 6,8
I7: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C1,B3: 1.. / C1 = 1  =>  0 pairs (X) / B3 = 1  =>  4 pairs (_)
H8,I9: 1.. / H8 = 1  =>  5 pairs (_) / I9 = 1  =>  5 pairs (_)
I1,I2: 2.. / I1 = 2  =>  4 pairs (_) / I2 = 2  => 12 pairs (_)
A5,C5: 2.. / A5 = 2  => 19 pairs (_) / C5 = 2  =>  0 pairs (X)
D6,E6: 2.. / D6 = 2  =>  5 pairs (_) / E6 = 2  => 17 pairs (_)
E7,F7: 2.. / E7 = 2  =>  0 pairs (X) / F7 = 2  => 19 pairs (_)
B5,B9: 4.. / B5 = 4  =>  0 pairs (X) / B9 = 4  =>  4 pairs (_)
D3,E3: 7.. / D3 = 7  =>  4 pairs (_) / E3 = 7  =>  4 pairs (_)
A4,C4: 7.. / A4 = 7  =>  0 pairs (X) / C4 = 7  =>  6 pairs (_)
G5,I5: 7.. / G5 = 7  =>  4 pairs (_) / I5 = 7  =>  0 pairs (X)
A1,B2: 8.. / A1 = 8  =>  0 pairs (X) / B2 = 8  =>  5 pairs (_)
A4,B4: 8.. / A4 = 8  =>  5 pairs (_) / B4 = 8  =>  0 pairs (X)
E7,E9: 8.. / E7 = 8  =>  0 pairs (X) / E9 = 8  =>  4 pairs (_)
B2,I2: 8.. / B2 = 8  =>  5 pairs (_) / I2 = 8  =>  0 pairs (X)
A1,A4: 8.. / A1 = 8  =>  0 pairs (X) / A4 = 8  =>  5 pairs (_)
B2,B4: 8.. / B2 = 8  =>  5 pairs (_) / B4 = 8  =>  0 pairs (X)
G8,G9: 9.. / G8 = 9  =>  5 pairs (_) / G9 = 9  =>  4 pairs (_)
C7,F7: 9.. / C7 = 9  => 19 pairs (_) / F7 = 9  =>  0 pairs (X)
* DURATION: 0:00:22.910617  START: 05:15:42.170714  END: 05:16:05.081331 2017-05-01
* CP COUNT: (18)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,B7,H7,I7)
* .7.......5.....17...4..8..9...4..296...896....96..7...1..3..4...28.....5.......2.
* PAIR A6: 3,4 BLK 4
A5: 3,4,2                                # reduction candidate for 3,4
A5: 3,4 => CTR
* .719.....5.96..17.2.4178..9785413296.1289675..96257..1157329468928764315643581927
A5: 2                                    # 19 pairs
B5: 3,4,1,5                              # reduction candidate for 3,4
B5: 3,4                                  # 17 pairs
* PAIR A6: 3,4 ROW 6
H6: 3,4,1,5,8                            # reduction candidate for 3,4
H6: 3,4                                  #  8 pairs
I6: 3,4,1,8                              # reduction candidate for 3,4
I6: 3,4                                  #  7 pairs
* PAIR A6: 3,4 COL A
A8: 3,4,6,7,9                            # reduction candidate for 3,4
A8: 3,4                                  # 20 pairs
A9: 3,4,6,7,9                            # reduction candidate for 3,4
A9: 3,4 => CTR
* 97....86.58.96.17.614278..98.74..2962.1896743.96.27.1.169352487728.....5..5789621
A9: 6,7,9                                #  4 pairs
* PAIR B7: 5,6 BLK 7
B9: 5,6,3,4                              # reduction candidate for 5,6
B9: 5,6 => CTR
* 97.......582...17.634..85.9...4..29624.896...396..7...1.93.24...28.....5..3....2.
B9: 3,4                                  #  5 pairs
* PAIR B7: 5,6 ROW 7
E7: 5,6,2,7,8                            # reduction candidate for 5,6
E7: 5,6                                  # 19 pairs
E7: 2,7,8                                #  4 pairs
* PAIR H7: 6,8 BLK 9
G9: 6,8,3,7,9                            # reduction candidate for 6,8
G9: 6,8                                  #  8 pairs
G9: 3,7,9                                #  4 pairs
* PAIR H7: 6,8 ROW 7
E7: 6,8,2,5,7                            # reduction candidate for 6,8
E7: 6,8 => CTR
* 971.....2582...17...4..8..98.74..2962.58967...96..7...1593.24.7.28.....5..3....2.
E7: 2,5,7                                #  4 pairs
* PAIR H7: 6,8 COL H
H1: 6,8,3,4,5                            # reduction candidate for 6,8
H1: 6,8                                  # 10 pairs
H1: 3,4,5                                #  4 pairs
* PAIR I7: 7,8 BLK 9
G9: 7,8,3,6,9                            # reduction candidate for 7,8
G9: 7,8                                  #  9 pairs
I9: 7,8,1,3                              # reduction candidate for 7,8
I9: 7,8 => CTR
* 971.....2582...17...4..8..98.74..2962.58967...96..7...1593.246..28...315..3...92.
I9: 1,3                                  #  5 pairs
* PAIR I7: 7,8 ROW 7
E7: 7,8,2,5,6                            # reduction candidate for 7,8
E7: 7,8 => CTR
* 971.....2582...17...4..8..98.74..2962.5896....96..7...1593.246..28.....5..3....2.
E7: 2,5,6                                #  4 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0100-base-pr-000.dot
* REASONING
* DIS # A5: 3,4 => CTR => A5: 2
* DIS # A9: 3,4 => CTR => A9: 6,7,9
* DIS # B9: 5,6 => CTR => B9: 3,4
* DIS # E7: 6,8 => CTR => E7: 2,5,7
* DIS # I9: 7,8 => CTR => I9: 1,3
* DIS # E7: 7,8 => CTR => E7: 2,5,6
* CNT   6 HDP CHAINS /  23 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,B7,H7,I7)
* .7.......5.....17...4..8..9...4..296...896....96..7...1..3..4...28.....5.......2.
* PAIR A6: 3,4 BLK 4
A5: 3,4,2                                # reduction candidate for 3,4
A5: 3,4 => CTR
* .719.....5.96..17.2.4178..9785413296.1289675..96257..1157329468928764315643581927
B5: 3,4,5                                # reduction candidate for 3,4
B5: 3,4                                  # 17 pairs
* RESTART
* PAIR A6: 3,4 BLK 4
B5: 3,4,5                                # reduction candidate for 3,4
B5: 5 => CTR
* 97.541.6.58..63174614728..9837415296251896743496237...169352487.28.74..5745.89321
* PAIR A6: 3,4 ROW 6
I6: 3,4,1,8                              # reduction candidate for 3,4
I6: 3,4 => SOLVED
* 972135648583964172614278539857413296231896754496527813169352487328741965745689321
* DURATION: 0:00:07.761739  START: 05:16:20.919492  END: 05:16:28.681231 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0100-base-pr-001.dot
* REASONING
* DIS # A5: 3,4 => CTR => A5: 2
* DIS A5: 2 # B5: 5 => CTR => B5: 3,4
* PRF A5: 2 + B5: 3,4 # I6: 3,4 => SOL
* STA A5: 2 + B5: 3,4 + I6: 3,4
* CNT   3 HDP CHAINS /   5 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=100

Solution

position: 972135648583964172614278539857413296231896754496527813169352487328741965745689321 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 # A5: 3,4 => CTR => A5: 2
* INC # A5: 2 => UNS
* INC # B5: 3,4 => UNS
* INC # H6: 3,4 => UNS
* INC # I6: 3,4 => UNS
* INC # A8: 3,4 => UNS
* DIS # A9: 3,4 => CTR => A9: 6,7,9
* INC # A9: 6,7,9 => UNS
* DIS # B9: 5,6 => CTR => B9: 3,4
* INC # B9: 3,4 => UNS
* INC # E7: 5,6 => UNS
* INC # E7: 2,7,8 => UNS
* INC # G9: 6,8 => UNS
* INC # G9: 3,7,9 => UNS
* DIS # E7: 6,8 => CTR => E7: 2,5,7
* INC # E7: 2,5,7 => UNS
* INC # H1: 6,8 => UNS
* INC # H1: 3,4,5 => UNS
* INC # G9: 7,8 => UNS
* DIS # I9: 7,8 => CTR => I9: 1,3
* INC # I9: 1,3 => UNS
* DIS # E7: 7,8 => CTR => E7: 2,5,6
* INC # E7: 2,5,6 => UNS
* CNT  23 HDP CHAINS /  23 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A5: 3,4 => CTR => A5: 2
* INC A5: 2 # B5: 3,4 => UNS
* INC A5: 2 # B5: 3,4 => UNS
* DIS A5: 2 # B5: 5 => CTR => B5: 3,4
* PRF A5: 2 + B5: 3,4 # I6: 3,4 => SOL
* STA A5: 2 + B5: 3,4 + I6: 3,4
* CNT   5 HDP CHAINS /   5 HYP OPENED