Analysis of zz-www.sudokuwiki.org-0132-base.sdk

Contents

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=132

level: medium

Sudoku from http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=132

position: 2.7..6..4..4.5.8.....4......3...1..9.4..7..6.1......8......3.....1.8.5..5..1..9.6 initial

Autosolve

position: 2.7..6..4..4.5.8.....4..6...3...1..9.4..7..6.1......8....5.3..8..1.8.5..5..1..9.6 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # H1: 1,3 => CTR => H1: 5,9
* DIS # H3: 1,3 => CTR => H3: 2,5,7,9
* DIS # I3: 1,3 => CTR => I3: 2,5,7
* DIS # C5: 8,9 => CTR => C5: 2,5
* DIS # D5: 8,9 => CTR => D5: 2,3
* DIS # A3: 3 => CTR => A3: 8,9
* DIS # E7: 2,4 => CTR => E7: 6,9
* CNT   7 HDP CHAINS /  27 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 # H1: 1,3 => CTR => H1: 5,9
* DIS H1: 5,9 # H3: 1,3 => CTR => H3: 2,5,7,9
* DIS H1: 5,9 + H3: 2,5,7,9 # I3: 1,3 => CTR => I3: 2,5,7
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 # E1: 9 => CTR => E1: 1,3
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # C5: 8,9 => CTR => C5: 2,5
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 # D5: 8,9 => CTR => D5: 2,3
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 # A3: 3 => CTR => A3: 8,9
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 # A8: 4,7 => CTR => A8: 3,6
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 # B1: 8,9 => CTR => B1: 5
* PRF H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5 => SOL
* STA H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5
* CNT  10 HDP CHAINS /  20 HYP OPENED

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

Details

Positions

2.7..6..4..4.5.8.....4......3...1..9.4..7..6.1......8......3.....1.8.5..5..1..9.6 initial
2.7..6..4..4.5.8.....4..6...3...1..9.4..7..6.1......8....5.3..8..1.8.5..5..1..9.6 autosolve
257816394364759821819432675738641259945278163126395487492563718671984532583127946 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (3)
G1: 1,3
A5: 8,9
E9: 2,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E1,E3: 1.. / E1 = 1  =>  6 pairs (_) / E3 = 1  =>  4 pairs (_)
G5,I5: 1.. / G5 = 1  =>  6 pairs (_) / I5 = 1  =>  4 pairs (_)
G7,H7: 1.. / G7 = 1  => 16 pairs (_) / H7 = 1  =>  3 pairs (_)
A8,C9: 3.. / A8 = 3  =>  9 pairs (_) / C9 = 3  => 12 pairs (_)
C9,H9: 3.. / C9 = 3  => 12 pairs (_) / H9 = 3  =>  9 pairs (_)
C3,C9: 3.. / C3 = 3  =>  9 pairs (_) / C9 = 3  => 12 pairs (_)
A7,A8: 4.. / A7 = 4  =>  3 pairs (_) / A8 = 4  =>  0 pairs (X)
F5,F6: 5.. / F5 = 5  =>  0 pairs (X) / F6 = 5  =>  7 pairs (_)
B1,H1: 5.. / B1 = 5  => 13 pairs (_) / H1 = 5  =>  3 pairs (_)
C4,H4: 5.. / C4 = 5  =>  3 pairs (_) / H4 = 5  => 13 pairs (_)
A2,B2: 6.. / A2 = 6  =>  5 pairs (_) / B2 = 6  => 17 pairs (_)
E7,D8: 6.. / E7 = 6  =>  7 pairs (_) / D8 = 6  =>  6 pairs (_)
A4,B6: 7.. / A4 = 7  =>  4 pairs (_) / B6 = 7  =>  0 pairs (X)
D2,D8: 7.. / D2 = 7  =>  4 pairs (_) / D8 = 7  => 14 pairs (_)
D1,F3: 8.. / D1 = 8  => 12 pairs (_) / F3 = 8  =>  0 pairs (X)
B9,C9: 8.. / B9 = 8  => 12 pairs (_) / C9 = 8  =>  0 pairs (X)
B1,D1: 8.. / B1 = 8  =>  0 pairs (X) / D1 = 8  => 12 pairs (_)
F3,F5: 8.. / F3 = 8  =>  0 pairs (X) / F5 = 8  => 12 pairs (_)
* DURATION: 0:00:22.595980  START: 05:59:03.965475  END: 05:59:26.561455 2017-05-01
* CP COUNT: (18)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,E9,G1)
* 2.7..6..4..4.5.8.....4..6...3...1..9.4..7..6.1......8....5.3..8..1.8.5..5..1..9.6
* PAIR G1: 1,3 BLK 3
H1: 1,3,5,9                              # reduction candidate for 1,3
H1: 1,3 => CTR
* 25789613461435.8973..41762583264175994527836117693548272.563..8.617895.35.3124976
H1: 5,9                                  #  4 pairs
H2: 1,3,2,7,9                            # reduction candidate for 1,3
H2: 1,3                                  #  7 pairs
I2: 1,3,2,7                              # reduction candidate for 1,3
I2: 1,3                                  #  6 pairs
H3: 1,3,2,5,7,9                          # reduction candidate for 1,3
H3: 1,3 => CTR
* 2.7..6..461435.8.....4..6...3...1..9.4..7.3611...3..8....5.3..8..178.5.35.31..9.6
H3: 2,5,7,9                              #  3 pairs
I3: 1,3,2,5,7                            # reduction candidate for 1,3
I3: 1,3 => CTR
* 2.7.163.461435.897...497621.356.1..9.4..7.1631...3..85...563.18.617895.25..1..9.6
I3: 2,5,7                                #  3 pairs
* PAIR G1: 1,3 ROW 1
E1: 1,3,9                                # reduction candidate for 1,3
E1: 9                                    #  8 pairs
E1: 1,3                                  #  6 pairs
* PAIR G1: 1,3 COL G
G5: 1,3,2                                # reduction candidate for 1,3
G5: 2                                    #  8 pairs
G5: 1,3                                  #  4 pairs
* PAIR A5: 8,9 BLK 4
C5: 8,9,2,5                              # reduction candidate for 8,9
C5: 8,9 => CTR
* 287..6.546147528939534186..735861429849.7..6.1......8.4..5.32183.168.5475.81.7936
C5: 2,5                                  #  4 pairs
* PAIR A5: 8,9 ROW 5
D5: 8,9,2,3                              # reduction candidate for 8,9
D5: 8,9 => CTR
* 287396154614.5.8939534186..7358614298429753611..23478547.5.3.183.1.8.54.5.81..936
D5: 2,3                                  #  4 pairs
F5: 8,9,2,5                              # reduction candidate for 8,9
F5: 8,9                                  # 10 pairs
* PAIR A5: 8,9 COL A
A3: 8,9,3                                # reduction candidate for 8,9
A3: 3 => CTR
* 2.78361.4614.5.8.73.841762583..41.5994537826117..95483.295637.8.61.8.53258312.9.6
A3: 8,9                                  #  6 pairs
* PAIR E9: 2,4 BLK 8
E7: 2,4,6,9                              # reduction candidate for 2,4
E7: 2,4 => CTR
* 287..6.54.14752893953418627735..1..9.4..75.6.1....4.85...523..8371689542528147936
E7: 6,9                                  #  4 pairs
F8: 2,4,7,9                              # reduction candidate for 2,4
F8: 2,4                                  #  9 pairs
F9: 2,4,7                                # reduction candidate for 2,4
F9: 2,4                                  # 10 pairs
* PAIR E9: 2,4 ROW 9
H9: 2,4,3,7                              # reduction candidate for 2,4
H9: 2,4                                  # 18 pairs
H9: 3,7                                  #  4 pairs
* PAIR E9: 2,4 COL E
E4: 2,4,6                                # reduction candidate for 2,4
E4: 2,4                                  #  5 pairs
E6: 2,4,3,6,9                            # reduction candidate for 2,4
E6: 2,4                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuwiki.org-0132-base-pr-000.dot
* REASONING
* DIS # H1: 1,3 => CTR => H1: 5,9
* DIS # H3: 1,3 => CTR => H3: 2,5,7,9
* DIS # I3: 1,3 => CTR => I3: 2,5,7
* DIS # C5: 8,9 => CTR => C5: 2,5
* DIS # D5: 8,9 => CTR => D5: 2,3
* DIS # A3: 3 => CTR => A3: 8,9
* DIS # E7: 2,4 => CTR => E7: 6,9
* CNT   7 HDP CHAINS /  27 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,E9,G1)
* 2.7..6..4..4.5.8.....4..6...3...1..9.4..7..6.1......8....5.3..8..1.8.5..5..1..9.6
* PAIR G1: 1,3 BLK 3
H1: 1,3,5,9                              # reduction candidate for 1,3
H1: 1,3 => CTR
* 25789613461435.8973..41762583264175994527836117693548272.563..8.617895.35.3124976
H2: 1,3,2,7,9                            # reduction candidate for 1,3
H2: 1,3                                  #  7 pairs
I2: 1,3,2,7                              # reduction candidate for 1,3
I2: 1,3                                  #  6 pairs
H3: 1,3,2,5,7,9                          # reduction candidate for 1,3
H3: 1,3 => CTR
* 2.7..6..461435.8.....4..6...3...1..9.4..7.3611...3..8....5.3..8..178.5.35.31..9.6
I3: 1,3,2,5,7                            # reduction candidate for 1,3
I3: 1,3 => CTR
* 2.7.163.461435.897...497621.356.1..9.4..7.1631...3..85...563.18.617895.25..1..9.6
* PAIR G1: 1,3 ROW 1
E1: 1,3,9                                # reduction candidate for 1,3
E1: 9 => CTR
* 287396154614.5.8939534186..73586142984..753611...3478547.5.3.183.1.8.54.5.81..936
* PAIR G1: 1,3 COL G
G5: 1,3,2                                # reduction candidate for 1,3
G5: 2                                    #  8 pairs
G5: 1,3                                  #  7 pairs
* PAIR RESTART
* PAIR G1: 1,3 BLK 3
H2: 1,3,2,7,9                            # reduction candidate for 1,3
H2: 1,3                                  #  9 pairs
I2: 1,3,2,7                              # reduction candidate for 1,3
I2: 1,3                                  #  8 pairs
* PAIR G1: 1,3 COL G
G5: 1,3,2                                # reduction candidate for 1,3
G5: 2                                    #  8 pairs
G5: 1,3                                  #  7 pairs
* PAIR A5: 8,9 BLK 4
C5: 8,9,2,5                              # reduction candidate for 8,9
C5: 8,9 => CTR
* 2879361546147528939534186727358614298492753611.23.47854765.32183.168.5475.81.7936
* PAIR A5: 8,9 ROW 5
D5: 8,9,2,3                              # reduction candidate for 8,9
D5: 8,9 => CTR
* 2879.6.54..4.5.8.....4.86..835..1..9942875.6.176....85..95.3.18..1.895..528147936
* RESTART
* PAIR A5: 8,9 COL A
A3: 8,9,3                                # reduction candidate for 8,9
A3: 3 => CTR
* 2.78361.4614.5.8.73.841762583..41.5994537826117..95483.295637.8.61.8.53258312.9.6
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A2,A3,A4,A5,B9,C5,C9,D1,D5,E1,E4,E7,F5,F9,G1,H1)
* 2.7..6..4..4.5.8.....4..6...3...1..9.4..7..6.1....5.8....5.3..8..1.8.5..5..12.9.6
* PAIR A2: 3,6 COL A
A8: 3,6,4,7                              # reduction candidate for 3,6
A8: 4,7 => CTR
* 2578163943647598...1.4326...382.1.59945378.6.1..9.5.83...593..8.9168.53258312.9.6
* PAIR RESTART
* PAIR A3: 8,9 BLK 1
B1: 8,9,5                                # reduction candidate for 8,9
B1: 8,9 => CTR
* 2.7..6.54..4.5.8...5.41.6..7358614298423791651..245.8.4..593218..1.8.5..5..12.9.6
B1: 5 => SOLVED
* 257816394364759821819432675738641259945278163126395487492563718671984532583127946
* DURATION: 0:00:18.224070  START: 05:59:44.964826  END: 06:00:03.188896 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuwiki.org-0132-base-pr-001.dot
* REASONING
* DIS # H1: 1,3 => CTR => H1: 5,9
* DIS H1: 5,9 # H3: 1,3 => CTR => H3: 2,5,7,9
* DIS H1: 5,9 + H3: 2,5,7,9 # I3: 1,3 => CTR => I3: 2,5,7
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 # E1: 9 => CTR => E1: 1,3
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # C5: 8,9 => CTR => C5: 2,5
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 # D5: 8,9 => CTR => D5: 2,3
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 # A3: 3 => CTR => A3: 8,9
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 # A8: 4,7 => CTR => A8: 3,6
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 # B1: 8,9 => CTR => B1: 5
* PRF H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5 => SOL
* STA H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5
* CNT  10 HDP CHAINS /  20 HYP OPENED

Header Info

http://www.sudokuwiki.org/Print_Weekly_Sudoku.asp?unsolvable=132

Solution

position: 257816394364759821819432675738641259945278163126395487492563718671984532583127946 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 # H1: 1,3 => CTR => H1: 5,9
* INC # H1: 5,9 => UNS
* INC # H2: 1,3 => UNS
* INC # I2: 1,3 => UNS
* DIS # H3: 1,3 => CTR => H3: 2,5,7,9
* INC # H3: 2,5,7,9 => UNS
* DIS # I3: 1,3 => CTR => I3: 2,5,7
* INC # I3: 2,5,7 => UNS
* INC # E1: 1,3 => UNS
* INC # E1: 9 => UNS
* INC # G5: 1,3 => UNS
* INC # G5: 2 => UNS
* DIS # C5: 8,9 => CTR => C5: 2,5
* INC # C5: 2,5 => UNS
* DIS # D5: 8,9 => CTR => D5: 2,3
* INC # D5: 2,3 => UNS
* INC # F5: 8,9 => UNS
* INC # A3: 8,9 => UNS
* DIS # A3: 3 => CTR => A3: 8,9
* DIS # E7: 2,4 => CTR => E7: 6,9
* INC # E7: 6,9 => UNS
* INC # F8: 2,4 => UNS
* INC # F9: 2,4 => UNS
* INC # H9: 2,4 => UNS
* INC # H9: 3,7 => UNS
* INC # E4: 2,4 => UNS
* INC # E6: 2,4 => UNS
* CNT  27 HDP CHAINS /  27 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # H1: 1,3 => CTR => H1: 5,9
* INC H1: 5,9 # H2: 1,3 => UNS
* INC H1: 5,9 # I2: 1,3 => UNS
* DIS H1: 5,9 # H3: 1,3 => CTR => H3: 2,5,7,9
* DIS H1: 5,9 + H3: 2,5,7,9 # I3: 1,3 => CTR => I3: 2,5,7
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 # E1: 1,3 => UNS
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 # E1: 9 => CTR => E1: 1,3
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # G5: 1,3 => UNS
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # G5: 2 => UNS
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # H2: 1,3 => UNS
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # I2: 1,3 => UNS
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # G5: 1,3 => UNS
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # G5: 2 => UNS
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 # C5: 8,9 => CTR => C5: 2,5
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 # D5: 8,9 => CTR => D5: 2,3
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 # A3: 8,9 => UNS
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 # A3: 3 => CTR => A3: 8,9
* INC H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 # A8: 3,6 => UNS
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 # A8: 4,7 => CTR => A8: 3,6
* DIS H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 # B1: 8,9 => CTR => B1: 5
* PRF H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5 => SOL
* STA H1: 5,9 + H3: 2,5,7,9 + I3: 2,5,7 + E1: 1,3 + C5: 2,5 + D5: 2,3 + A3: 8,9 + A8: 3,6 + B1: 5
* CNT  21 HDP CHAINS /  20 HYP OPENED