Analysis of zz-sudoku-de-651186-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .8......9...328..71....764..1...3.....7...8.....5...2..267....43..496...4......5. initial

Autosolve

position: 785...239...32851713295764821...3..55.7...8.3..35...21.267.5..435.496..247.....56 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B2: 4 => SOL
* DIS # A6: 6,9 => CTR => A6: 8
* PRF # A6: 8 => SOL
* DIS # B2: 6 => CTR => B2: 4,9
* PRF # C4: 4,9 => SOL
* DIS # C4: 8 => CTR => C4: 4,9
* DIS # E1: 4 => CTR => E1: 1,6
* DIS # D5: 1,6 => CTR => D5: 2
* DIS # E1: 1,4 => CTR => E1: 6
* PRF # E4: 6,8 => SOL
* DIS # E6: 6,8 => CTR => E6: 4,7
* PRF # E6: 4,7 => SOL
* DIS # F5: 4,9 => CTR => F5: 1,2
* DIS # B6: 4,9 => CTR => B6: 6
* PRF # G6: 4,9 => SOL
* DIS # G6: 7 => CTR => G6: 4,9
* PRF # H4: 6,9 => SOL
* DIS # H4: 7 => CTR => H4: 6,9
* DIS # A6: 6 => CTR => A6: 8,9
* DIS # G9: 3 => CTR => G9: 1,9
* DIS # E9: 8 => CTR => E9: 1,3
* DIS # D9: 1,2 => CTR => D9: 8
* DIS # F5: 4,9 => CTR => F5: 1,2
* DIS # G9: 1,3 => CTR => G9: 9
* PRF # G9: 9 => SOL
* CNT  25 HDP CHAINS /  42 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 # B2: 4 => SOL
* STA B2: 4
* CNT   1 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.8......9...328..71....764..1...3.....7...8.....5...2..267....43..496...4......5. initial
785...239...32851713295764821...3..55.7...8.3..35...21.267.5..435.496..247.....56 autosolve
785164239649328517132957648214683795597241863863579421926715384358496172471832956 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
A2: 6,9
C2: 4,9
D1: 1,6
F1: 1,4
D4: 6,8
F6: 4,9
H5: 6,9
A7: 8,9
C8: 1,8
C9: 1,9
E7: 1,3
F9: 1,2
G7: 1,3
H7: 8,9
G8: 1,7
H8: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C8,C9: 1.. / C8 = 1  =>  0 pairs (X) / C9 = 1  =>  0 pairs (_)
E7,G7: 1.. / E7 = 1  => 17 pairs (_) / G7 = 1  =>  0 pairs (X)
C8,G8: 1.. / C8 = 1  =>  0 pairs (X) / G8 = 1  =>  0 pairs (_)
D5,F5: 2.. / D5 = 2  => 16 pairs (_) / F5 = 2  =>  0 pairs (X)
D9,F9: 2.. / D9 = 2  =>  0 pairs (X) / F9 = 2  => 16 pairs (_)
D5,D9: 2.. / D5 = 2  => 16 pairs (_) / D9 = 2  =>  0 pairs (X)
F5,F9: 2.. / F5 = 2  =>  0 pairs (X) / F9 = 2  => 16 pairs (_)
E7,E9: 3.. / E7 = 3  =>  0 pairs (X) / E9 = 3  => 17 pairs (_)
G7,G9: 3.. / G7 = 3  => 17 pairs (_) / G9 = 3  =>  0 pairs (X)
E7,G7: 3.. / E7 = 3  =>  0 pairs (X) / G7 = 3  => 17 pairs (_)
E9,G9: 3.. / E9 = 3  => 17 pairs (_) / G9 = 3  =>  0 pairs (X)
B2,C2: 4.. / B2 = 4  =>  0 pairs (*) / C2 = 4  =>  0 pairs (X)
E1,F1: 4.. / E1 = 4  =>  0 pairs (X) / F1 = 4  => 19 pairs (_)
G4,G6: 4.. / G4 = 4  => 18 pairs (_) / G6 = 4  =>  0 pairs (*)
C2,C4: 4.. / C2 = 4  => 17 pairs (_) / C4 = 4  =>  0 pairs (*)
A2,B2: 6.. / A2 = 6  => 17 pairs (_) / B2 = 6  =>  0 pairs (X)
D1,E1: 6.. / D1 = 6  =>  0 pairs (X) / E1 = 6  => 21 pairs (_)
H4,H5: 6.. / H4 = 6  =>  0 pairs (X) / H5 = 6  => 20 pairs (_)
A2,A6: 6.. / A2 = 6  => 17 pairs (_) / A6 = 6  =>  0 pairs (X)
E4,E6: 7.. / E4 = 7  =>  0 pairs (X) / E6 = 7  =>  0 pairs (_)
G8,H8: 7.. / G8 = 7  =>  0 pairs (X) / H8 = 7  =>  0 pairs (_)
E6,G6: 7.. / E6 = 7  =>  0 pairs (*) / G6 = 7  =>  0 pairs (X)
H4,H8: 7.. / H4 = 7  =>  0 pairs (X) / H8 = 7  =>  0 pairs (_)
C4,A6: 8.. / C4 = 8  =>  0 pairs (X) / A6 = 8  =>  0 pairs (_)
A7,C8: 8.. / A7 = 8  =>  0 pairs (X) / C8 = 8  =>  0 pairs (_)
D9,E9: 8.. / D9 = 8  => 19 pairs (_) / E9 = 8  =>  0 pairs (X)
H7,H8: 8.. / H7 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
A6,E6: 8.. / A6 = 8  =>  0 pairs (*) / E6 = 8  =>  0 pairs (X)
A7,H7: 8.. / A7 = 8  =>  0 pairs (X) / H7 = 8  =>  0 pairs (_)
C8,H8: 8.. / C8 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
A6,A7: 8.. / A6 = 8  =>  0 pairs (*) / A7 = 8  =>  0 pairs (X)
C4,C8: 8.. / C4 = 8  =>  0 pairs (X) / C8 = 8  =>  0 pairs (_)
D4,D9: 8.. / D4 = 8  =>  0 pairs (X) / D9 = 8  => 19 pairs (_)
F5,F6: 9.. / F5 = 9  =>  0 pairs (X) / F6 = 9  => 18 pairs (_)
A7,C9: 9.. / A7 = 9  =>  0 pairs (*) / C9 = 9  =>  0 pairs (X)
H7,G9: 9.. / H7 = 9  =>  0 pairs (X) / G9 = 9  =>  0 pairs (_)
A7,H7: 9.. / A7 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
C9,G9: 9.. / C9 = 9  =>  0 pairs (X) / G9 = 9  =>  0 pairs (_)
* DURATION: 0:01:05.696076  START: 07:36:02.919310  END: 07:37:08.615386 2017-05-01
* CP COUNT: (38)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A7,C2,C8,C9,D1,D4,E7,F1,F6,F9,G7,G8,H5,H7,H8)
* 785...239...32851713295764821...3..55.7...8.3..35...21.267.5..435.496..247.....56
* PAIR A2: 6,9 BLK 1
B2: 6,9,4                                # reduction candidate for 6,9
B2: 4 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
B2: 6,9                                  # 17 pairs
* PAIR A2: 6,9 COL A
A6: 6,9,8                                # reduction candidate for 6,9
A6: 6,9 => CTR
* 785...239...3285171329576482186.3..55.7...863..358.7218267.5.9435.496..247.....56
A6: 8 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
* PAIR C2: 4,9 BLK 1
B2: 4,9,6                                # reduction candidate for 4,9
B2: 6 => CTR
* 785...239.6432851713295764821...3..55.7...8.36.358.7218267.5.9435.496..247.....56
B2: 4,9                                  # 17 pairs
* PAIR C2: 4,9 COL C
C4: 4,9,8                                # reduction candidate for 4,9
C4: 4,9 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
C4: 8 => CTR
* 785...239..43285171329576482186.3..55.7...863..358.7218267.5.9435.496..247.....56
* PAIR D1: 1,6 BLK 2
E1: 1,6,4                                # reduction candidate for 1,6
E1: 4 => CTR
* 785641239...32851713295764821.8.3..55.7...8.38.35...219267.5.843584961724712...56
E1: 1,6                                  # 19 pairs
* PAIR D1: 1,6 COL D
D5: 1,6,2                                # reduction candidate for 1,6
D5: 1,6 => CTR
* 785..4239...32851713295764821.8.39.5597.428638635794219267.5..435.496..247.281356
D5: 2                                    # 16 pairs
* PAIR F1: 1,4 BLK 2
E1: 1,4,6                                # reduction candidate for 1,4
E1: 1,4 => CTR
* 7856..239...32851713295764821.8.3..55.7...8.38.35...219267.5.843584961724712...56
E1: 6                                    # 21 pairs
* PAIR F1: 1,4 COL F
F5: 1,4,2,9                              # reduction candidate for 1,4
F5: 1,4                                  # 19 pairs
F5: 2,9                                  # 17 pairs
* PAIR D4: 6,8 BLK 5
E4: 6,8,4,7                              # reduction candidate for 6,8
E4: 6,8 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
E4: 4,7                                  # 17 pairs
E6: 6,8,4,7                              # reduction candidate for 6,8
E6: 6,8 => CTR
* 785...239...32851713295764821..734.55.72..8.3..35..721926715384358496172471832956
E6: 4,7 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
* PAIR F6: 4,9 BLK 5
F5: 4,9,1,2                              # reduction candidate for 4,9
F5: 4,9 => CTR
* 785..1239..43285171329576482186.3..55.721.8.3..35...21.267351.4351496782479.82356
F5: 1,2                                  # 19 pairs
* PAIR F6: 4,9 ROW 6
B6: 4,9,6                                # reduction candidate for 4,9
B6: 4,9 => CTR
* 785...239..43285171329576482198734.55.7...8.3..35..721.267.5..435.496172471..2956
B6: 6                                    # 18 pairs
G6: 4,9,7                                # reduction candidate for 4,9
G6: 4,9 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
G6: 7 => CTR
* 785...239..4328517132957648219.734655.72..8938.35.9721926715..435.496172471..2956
* PAIR H5: 6,9 BLK 6
H4: 6,9,7                                # reduction candidate for 6,9
H4: 6,9 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
H4: 7 => CTR
* 785...239..4328517132957648218643975547.19863..357..21.267.5.9435.496782479....56
* PAIR H5: 6,9 ROW 5
B5: 6,9,4                                # reduction candidate for 6,9
B5: 6,9                                  # 21 pairs
B5: 4                                    # 19 pairs
* PAIR A7: 8,9 COL A
A6: 8,9,6                                # reduction candidate for 8,9
A6: 6 => CTR
* 785...239...3285171329576482186.3..55.7...8636.358.7218267.5.9435.496..247.....56
A6: 8,9                                  # 17 pairs
* PAIR C9: 1,9 ROW 9
G9: 1,9,3                                # reduction candidate for 1,9
G9: 3 => CTR
* 785...239..43285171329576482186.39755.7...863..35...21.267.5.9435.496.82479...356
G9: 1,9                                  # 17 pairs
* PAIR E7: 1,3 BLK 8
E9: 1,3,8                                # reduction candidate for 1,3
E9: 8 => CTR
* 785...239..43285171329576482186.3.755.7...863..357..21826735194351496782479.8.356
E9: 1,3                                  # 19 pairs
* PAIR F9: 1,2 BLK 8
D9: 1,2,8                                # reduction candidate for 1,2
D9: 1,2 => CTR
* 785...239...32851713295764821.8.3..55.7...8.38.35...219267.5.843584961724712...56
D9: 8                                    # 19 pairs
* PAIR F9: 1,2 COL F
F5: 1,2,4,9                              # reduction candidate for 1,2
F5: 4,9 => CTR
* 785..1239..43285171329576482186.3..55.721.8.3..35...21.267351.4351496782479.82356
F5: 1,2                                  # 19 pairs
* PAIR G7: 1,3 BLK 9
G9: 1,3,9                                # reduction candidate for 1,3
G9: 1,3 => CTR
* 785...239..43285171329576482186.39755.7...863..35...21.267.5.9435.496.82479....56
G9: 9 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
* INCONCLUSIVE
* SAVE PR GRAPH zz-sudoku-de-651186-base-pr-000.dot
* REASONING
* PRF # B2: 4 => SOL
* DIS # A6: 6,9 => CTR => A6: 8
* PRF # A6: 8 => SOL
* DIS # B2: 6 => CTR => B2: 4,9
* PRF # C4: 4,9 => SOL
* DIS # C4: 8 => CTR => C4: 4,9
* DIS # E1: 4 => CTR => E1: 1,6
* DIS # D5: 1,6 => CTR => D5: 2
* DIS # E1: 1,4 => CTR => E1: 6
* PRF # E4: 6,8 => SOL
* DIS # E6: 6,8 => CTR => E6: 4,7
* PRF # E6: 4,7 => SOL
* DIS # F5: 4,9 => CTR => F5: 1,2
* DIS # B6: 4,9 => CTR => B6: 6
* PRF # G6: 4,9 => SOL
* DIS # G6: 7 => CTR => G6: 4,9
* PRF # H4: 6,9 => SOL
* DIS # H4: 7 => CTR => H4: 6,9
* DIS # A6: 6 => CTR => A6: 8,9
* DIS # G9: 3 => CTR => G9: 1,9
* DIS # E9: 8 => CTR => E9: 1,3
* DIS # D9: 1,2 => CTR => D9: 8
* DIS # F5: 4,9 => CTR => F5: 1,2
* DIS # G9: 1,3 => CTR => G9: 9
* PRF # G9: 9 => SOL
* CNT  25 HDP CHAINS /  42 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A7,C2,C8,C9,D1,D4,E7,F1,F6,F9,G7,G8,H5,H7,H8)
* 785...239...32851713295764821...3..55.7...8.3..35...21.267.5..435.496..247.....56
* PAIR A2: 6,9 BLK 1
B2: 6,9,4                                # reduction candidate for 6,9
B2: 4 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
* DURATION: 0:00:02.983297  START: 07:37:50.056652  END: 07:37:53.039949 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-sudoku-de-651186-base-pr-001.dot
* REASONING
* PRF # B2: 4 => SOL
* STA B2: 4
* CNT   1 HDP CHAINS /   2 HYP OPENED

Header Info

http://www.sudokus.de/651186.html
sehr schwierig

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

* PAIR REDUCTION ..
* ROUND 1: 785...239...32851713295764821...3..55.7...8.3..35...21.267.5..435.496..247.....56
A2: 6,9
B2: 4,6,9                                # reduction candidate for 6,9
B2: 4 => SOLVED
* 785164239649328517132957648214683795597241863863579421926715384358496172471832956
* SOLVED!

--------------------------------------------------
* AUTO ..
A1 = 7                # set value
H2 = 1                # set value
H1: 3                 # naked single
G2: 5                 # naked single
D3 = 9                # set value
E3 = 5                # set value
B3: 3                 # naked single
I3 = 8                # set value
I9 = 6                # set value
I4: 5                 # naked single
G1: 2..               # hidden single
F7: 5..               # hidden single
C3: 2..               # hidden single
I8: 2..               # hidden single
G1 = 2                # set value
H1 = 3                # set value
G2 = 5                # set value
B3 = 3                # set value
C3: 2                 # naked single
C3 = 2                # set value
I4 = 5                # set value
F7 = 5                # set value
I8 = 2                # set value
C1: 5..               # hidden single
C6: 3..               # hidden single
I5: 3..               # hidden single
A5: 5..               # hidden single
C1 = 5                # set value
A5 = 5                # set value
I5 = 3                # set value
I6: 1                 # naked single
C6 = 3                # set value
I6 = 1                # set value
A4: 2..               # hidden single
B8: 5..               # hidden single
A4 = 2                # set value
B8 = 5                # set value
B9: 7..               # hidden single
B9 = 7                # set value
E7,G7: 1,3.. => E7,G7 != 8,9 # hidden pair
Q8: 8.. = D9,E9: 8.. => C9 != 8

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

pair quad
E7: 1,3
G7: 1,3
E9: 1,3,8
G9: 1,3,9

* FORCE VALUE:: G9 = 9
G9 = 9                # set value
H7: 8                 # naked single
C9: 1                 # naked single
A7: 9..               # hidden single
G7: 3..               # hidden single
E9: 3..               # hidden single

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

highlight 7
observe that E4,E6 and G4,G6 are symmetrical
G4,G6,H4,H5 => G4,G5 = 4,9 or G=4 or G5 = 4

G9 != 9 leads to a contradiction very fast.

--------------------------------------------------
* DISABLE VALUE:: G9 != 9
* DISABLE VALUE:: G8 != 1
G8: 7                 # naked single
* DISABLE VALUE:: G6 != 7
* DISABLE VALUE:: G4 != 7
* DISABLE VALUE:: H4 != 9
* DISABLE VALUE:: H4 != 6
H4: 7                 # naked single
* DISABLE VALUE:: E6 != 8
* DISABLE VALUE:: E6 != 4
* DISABLE VALUE:: E6 != 6
E6: 7                 # naked single
* DISABLE VALUE:: A6 != 9
* DISABLE VALUE:: A6 != 6
A6: 8                 # naked single
* DISABLE VALUE:: A7 != 8
A7: 9                 # naked single
* DISABLE VALUE:: C9 != 9
C9: 1                 # naked single
* DISABLE VALUE:: C8 != 1
C8: 8                 # naked single
* DISABLE VALUE:: H8 != 8
H8: 7                 # naked single
* ANALYZE ..
G8,H8 = 7 => CTR
G8,H8 = 7 => CTR

|:step:| 02
--------------------------------------------------

Solution

position: 785164239649328517132957648214683795597241863863579421926715384358496172471832956 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: 6,9 => UNS
* PRF # B2: 4 => SOL
* DIS # A6: 6,9 => CTR => A6: 8
* PRF # A6: 8 => SOL
* INC # B2: 4,9 => UNS
* DIS # B2: 6 => CTR => B2: 4,9
* PRF # C4: 4,9 => SOL
* DIS # C4: 8 => CTR => C4: 4,9
* INC # E1: 1,6 => UNS
* DIS # E1: 4 => CTR => E1: 1,6
* DIS # D5: 1,6 => CTR => D5: 2
* INC # D5: 2 => UNS
* DIS # E1: 1,4 => CTR => E1: 6
* INC # E1: 6 => UNS
* INC # F5: 1,4 => UNS
* INC # F5: 2,9 => UNS
* PRF # E4: 6,8 => SOL
* INC # E4: 4,7 => UNS
* DIS # E6: 6,8 => CTR => E6: 4,7
* PRF # E6: 4,7 => SOL
* DIS # F5: 4,9 => CTR => F5: 1,2
* INC # F5: 1,2 => UNS
* DIS # B6: 4,9 => CTR => B6: 6
* INC # B6: 6 => UNS
* PRF # G6: 4,9 => SOL
* DIS # G6: 7 => CTR => G6: 4,9
* PRF # H4: 6,9 => SOL
* DIS # H4: 7 => CTR => H4: 6,9
* INC # B5: 6,9 => UNS
* INC # B5: 4 => UNS
* INC # A6: 8,9 => UNS
* DIS # A6: 6 => CTR => A6: 8,9
* INC # G9: 1,9 => UNS
* DIS # G9: 3 => CTR => G9: 1,9
* INC # E9: 1,3 => UNS
* DIS # E9: 8 => CTR => E9: 1,3
* DIS # D9: 1,2 => CTR => D9: 8
* INC # D9: 8 => UNS
* INC # F5: 1,2 => UNS
* DIS # F5: 4,9 => CTR => F5: 1,2
* DIS # G9: 1,3 => CTR => G9: 9
* PRF # G9: 9 => SOL
* CNT  42 HDP CHAINS /  42 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B2: 6,9 => UNS
* PRF # B2: 4 => SOL
* STA B2: 4
* CNT   2 HDP CHAINS /   2 HYP OPENED