Analysis of zz-sudoku-de-678907-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .1.5.6.7...3...8...4.3.2.5..91...63.6.......1.52...48..7.9.3.1...8...9...2.6.8.4. initial

Autosolve

position: 219586374563..18298473921567918..63.684.3..913521694874769.3.18138...96.925618743 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # D8: 4,7 => SOL
* DIS # D8: 2 => CTR => D8: 4,7
* PRF # E8: 2,5 => SOL
* PRF # E4: 4,5 => SOL
* DIS # E4: 2 => CTR => E4: 4,5
* PRF # F8: 4,5 => SOL
* DIS # F8: 7 => CTR => F8: 4,5
* DIS # D8: 4 => CTR => D8: 2,7
* PRF # F8: 4 => SOL
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* CNT  13 HDP CHAINS /  20 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 # D8: 4,7 => SOL
* STA D8: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.1.5.6.7...3...8...4.3.2.5..91...63.6.......1.52...48..7.9.3.1...8...9...2.6.8.4. initial
219586374563..18298473921567918..63.684.3..913521694874769.3.18138...96.925618743 autosolve
219586374563471829847392156791845632684237591352169487476953218138724965925618743 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (10)
D2: 4,7
E2: 4,7
F4: 4,5
D5: 2,7
F5: 5,7
I4: 2,5
G5: 2,5
E7: 2,5
G7: 2,5
I8: 2,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E4,D5: 2.. / E4 = 2  =>  0 pairs (X) / D5 = 2  =>  0 pairs (_)
I4,G5: 2.. / I4 = 2  =>  0 pairs (*) / G5 = 2  =>  0 pairs (X)
G7,I8: 2.. / G7 = 2  =>  0 pairs (*) / I8 = 2  =>  0 pairs (X)
E4,I4: 2.. / E4 = 2  =>  0 pairs (X) / I4 = 2  =>  0 pairs (_)
D5,G5: 2.. / D5 = 2  =>  0 pairs (*) / G5 = 2  =>  0 pairs (X)
E7,G7: 2.. / E7 = 2  =>  0 pairs (X) / G7 = 2  =>  0 pairs (_)
D5,D8: 2.. / D5 = 2  =>  0 pairs (*) / D8 = 2  =>  0 pairs (X)
G5,G7: 2.. / G5 = 2  =>  0 pairs (X) / G7 = 2  =>  0 pairs (_)
I4,I8: 2.. / I4 = 2  =>  0 pairs (*) / I8 = 2  =>  0 pairs (X)
D2,E2: 4.. / D2 = 4  =>  9 pairs (_) / E2 = 4  =>  0 pairs (X)
E4,F4: 4.. / E4 = 4  =>  0 pairs (*) / F4 = 4  =>  0 pairs (X)
D2,D8: 4.. / D2 = 4  =>  9 pairs (_) / D8 = 4  =>  0 pairs (X)
F4,F8: 4.. / F4 = 4  => 12 pairs (_) / F8 = 4  =>  0 pairs (*)
I4,G5: 5.. / I4 = 5  =>  0 pairs (X) / G5 = 5  =>  0 pairs (_)
G7,I8: 5.. / G7 = 5  =>  0 pairs (X) / I8 = 5  =>  0 pairs (_)
F5,G5: 5.. / F5 = 5  =>  0 pairs (X) / G5 = 5  =>  0 pairs (_)
E7,G7: 5.. / E7 = 5  =>  0 pairs (*) / G7 = 5  =>  0 pairs (X)
G5,G7: 5.. / G5 = 5  =>  0 pairs (*) / G7 = 5  =>  0 pairs (X)
I4,I8: 5.. / I4 = 5  =>  0 pairs (X) / I8 = 5  =>  0 pairs (_)
D2,E2: 7.. / D2 = 7  =>  0 pairs (X) / E2 = 7  =>  9 pairs (_)
D5,F5: 7.. / D5 = 7  =>  0 pairs (X) / F5 = 7  =>  0 pairs (_)
E2,E8: 7.. / E2 = 7  =>  9 pairs (_) / E8 = 7  =>  0 pairs (X)
F5,F8: 7.. / F5 = 7  =>  0 pairs (*) / F8 = 7  =>  0 pairs (X)
* DURATION: 0:00:40.560394  START: 07:46:26.093343  END: 07:47:06.653737 2017-05-01
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D2,D5,E2,E7,F4,F5,G5,G7,I4,I8)
* 219586374563..18298473921567918..63.684.3..913521694874769.3.18138...96.925618743
* PAIR D2: 4,7 COL D
D8: 4,7,2                                # reduction candidate for 4,7
D8: 4,7 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
D8: 2 => CTR
* 2195863745634718298473921567918..63.684735291352169487476923.18138...96.925618743
* PAIR E2: 4,7 COL E
E8: 4,7,2,5                              # reduction candidate for 4,7
E8: 2,5 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E8: 4,7                                  # 12 pairs
* PAIR F4: 4,5 BLK 5
E4: 4,5,2                                # reduction candidate for 4,5
E4: 4,5 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E4: 2 => CTR
* 219586374563..18298473921567918246356847352913521694874769.3.18138...96.925618743
* PAIR F4: 4,5 COL F
F8: 4,5,7                                # reduction candidate for 4,5
F8: 4,5 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
F8: 7 => CTR
* 219586374563..18298473921567918.463.684.35291352169487476923.18138...96.925618743
* PAIR D5: 2,7 COL D
D8: 2,7,4                                # reduction candidate for 2,7
D8: 4 => CTR
* 219586374563..18298473921567918..63.6842375913521694874769532181384..96.925618743
D8: 2,7                                  #  9 pairs
* PAIR F5: 5,7 COL F
F8: 5,7,4                                # reduction candidate for 5,7
F8: 4 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
F8: 5,7                                  # 12 pairs
* PAIR I4: 2,5 ROW 4
E4: 2,5,4                                # reduction candidate for 2,5
E4: 4 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E4: 2,5                                  # 12 pairs
* PAIR E7: 2,5 BLK 8
E8: 2,5,4,7                              # reduction candidate for 2,5
E8: 2,5 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E8: 4,7                                  # 12 pairs
* PAIR E7: 2,5 COL E
E4: 2,5,4                                # reduction candidate for 2,5
E4: 4 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E4: 2,5                                  # 12 pairs
* PAIR I8: 2,5 ROW 8
E8: 2,5,4,7                              # reduction candidate for 2,5
E8: 2,5 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
E8: 4,7                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-sudoku-de-678907-base-pr-000.dot
* REASONING
* PRF # D8: 4,7 => SOL
* DIS # D8: 2 => CTR => D8: 4,7
* PRF # E8: 2,5 => SOL
* PRF # E4: 4,5 => SOL
* DIS # E4: 2 => CTR => E4: 4,5
* PRF # F8: 4,5 => SOL
* DIS # F8: 7 => CTR => F8: 4,5
* DIS # D8: 4 => CTR => D8: 2,7
* PRF # F8: 4 => SOL
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* CNT  13 HDP CHAINS /  20 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D2,D5,E2,E7,F4,F5,G5,G7,I4,I8)
* 219586374563..18298473921567918..63.684.3..913521694874769.3.18138...96.925618743
* PAIR D2: 4,7 COL D
D8: 4,7,2                                # reduction candidate for 4,7
D8: 4,7 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
* DURATION: 0:00:01.790650  START: 07:47:38.202124  END: 07:47:39.992774 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-sudoku-de-678907-base-pr-001.dot
* REASONING
* PRF # D8: 4,7 => SOL
* STA D8: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

http://www.sudokus.de/678907.html
sehr schwierig

--------------------------------------------------
level: medium

* PAIR REDUCTION ..
* ROUND 1: 219586374563..18298473921567918..63.684.3..913521694874769.3.18138...96.925618743
D2: 4,7
D8: 2,4,7                                # reduction candidate for 4,7
D8: 4,7 => SOLVED
* 219586374563471829847392156791845632684237591352169487476953218138724965925618743
* SOLVED!
--------------------------------------------------

--------------------------------------------------
* AUTO ..
C1 = 9                # set value
C9: 5                 # naked single
A2 = 5                # set value
A7: 4                 # naked single
B2 = 6                # set value
C3: 7                 # naked single
B8: 3                 # naked single
C3 = 7                # set value
A3: 8                 # naked single
C5: 4                 # naked single
G3 = 1                # set value
B5 = 8                # set value
C5 = 4                # set value
A4: 7                 # naked single
E6 = 6                # set value
A7 = 4                # set value
I7 = 8                # set value
B8 = 3                # set value
A8: 1                 # naked single
C9 = 5                # set value
C7: 6                 # naked single
A1: 2..               # hidden single
I3: 6..               # hidden single
A6: 3..               # hidden single
E5: 3..               # hidden single
A9: 9..               # hidden single
D4: 8..               # hidden single
H8: 6..               # hidden single
A1 = 2                # set value
G1: 3                 # naked single
G1 = 3                # set value
I1: 4                 # naked single
G9: 7                 # naked single
I1 = 4                # set value
E1: 8                 # naked single
A3 = 8                # set value
E3: 9                 # naked single
E3 = 9                # set value
I3: 6                 # naked single
I3 = 6                # set value
A4 = 7                # set value
A6: 3                 # naked single
D4 = 8                # set value
E5 = 3                # set value
A6 = 3                # set value
C7 = 6                # set value
A8 = 1                # set value
A9: 9                 # naked single
H8 = 6                # set value
A9 = 9                # set value
G9 = 7                # set value
I9: 3                 # naked single
E9: 1                 # naked single
I9 = 3                # set value
I6: 7..               # hidden single
E1 = 8                # set value
I6 = 7                # set value
D6: 1                 # naked single
E9 = 1                # set value
H5: 9..               # hidden single
F6: 9..               # hidden single
I2: 9..               # hidden single
I2 = 9                # set value
H2: 2                 # naked single
H5 = 9                # set value
D6 = 1                # set value
F6: 9                 # naked single
F6 = 9                # set value
F2: 1..               # hidden single
F2 = 1                # set value
H2 = 2                # set value
* UNSOLVED!

|:step:| 00
--------------------------------------------------

highlight 2,5
* FORCE VALUE:: E4 = 4
E4 = 4                # set value
F4: 5                 # naked single
E2: 7                 # naked single
D2: 4..               # hidden single
D5: 2..               # hidden single
I4: 2..               # hidden single
F8: 4..               # hidden single

|:step:| 01
--------------------------------------------------

Solution

position: 219586374563471829847392156791845632684237591352169487476953218138724965925618743 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:

* PRF # D8: 4,7 => SOL
* DIS # D8: 2 => CTR => D8: 4,7
* INC # E8: 4,7 => UNS
* PRF # E8: 2,5 => SOL
* PRF # E4: 4,5 => SOL
* DIS # E4: 2 => CTR => E4: 4,5
* PRF # F8: 4,5 => SOL
* DIS # F8: 7 => CTR => F8: 4,5
* INC # D8: 2,7 => UNS
* DIS # D8: 4 => CTR => D8: 2,7
* INC # F8: 5,7 => UNS
* PRF # F8: 4 => SOL
* INC # E4: 2,5 => UNS
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* INC # E8: 4,7 => UNS
* INC # E4: 2,5 => UNS
* PRF # E4: 4 => SOL
* PRF # E8: 2,5 => SOL
* INC # E8: 4,7 => UNS
* CNT  20 HDP CHAINS /  20 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # D8: 4,7 => SOL
* STA D8: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED