Analysis of xx-top500-496-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...2..5..1..7......3....8...5..3.4.....6....2.8.......2......1.6.7..........5.... initial

Autosolve

position: 76.2.35.112.7.56..53....82795.13.4...716.8.52.8.5..1..2.5....1.6.7.....5813.5.... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS # F7: 4,9 => CTR => F7: 6
* DIS # H4: 7 => CTR => H4: 6,8
* DIS # H6: 3,9 => CTR => H6: 6,7
* DIS # G8: 3,9 => CTR => G8: 2
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # I7: 4,9 => SOL
* DIS # H8: 4,9 => CTR => H8: 3,8
* PRF # I7: 4,9 => SOL
* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS # F7: 4,9 => CTR => F7: 6
* CNT  11 HDP CHAINS /  40 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 # H8: 4,9 => CTR => H8: 3,8
* DIS H8: 3,8 # F7: 4,9 => CTR => F7: 6
* PRF H8: 3,8 + F7: 6 # I7: 4,9 => SOL
* STA H8: 3,8 + F7: 6 + I7: 4,9
* CNT   3 HDP CHAINS /  22 HYP OPENED

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

Details

Positions

...2..5..1..7......3....8...5..3.4.....6....2.8.......2......1.6.7..........5.... initial
76.2.35.112.7.56..53....82795.13.4...716.8.52.8.5..1..2.5....1.6.7.....5813.5.... autosolve
764283591128795634539461827952137468371648952486529173245876319697314285813952746 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (24)
C3: 4,9
D3: 4,9
E3: 1,6
F3: 1,6
H1: 4,9
C4: 2,6
A5: 3,4
A6: 3,4
C6: 2,6
F4: 2,7
E5: 4,9
E6: 2,7
F6: 4,9
I4: 6,8
G5: 3,9
B7: 4,9
B8: 4,9
D7: 3,8
E7: 6,7
D8: 3,8
E8: 1,2
D9: 4,9
F9: 2,7
G9: 2,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E3,F3: 1.. / E3 = 1  =>  0 pairs (X) / F3 = 1  => 19 pairs (_)
E8,F8: 1.. / E8 = 1  => 19 pairs (_) / F8 = 1  =>  0 pairs (X)
E3,E8: 1.. / E3 = 1  =>  0 pairs (X) / E8 = 1  => 19 pairs (_)
F3,F8: 1.. / F3 = 1  => 19 pairs (_) / F8 = 1  =>  0 pairs (X)
C4,C6: 2.. / C4 = 2  => 19 pairs (_) / C6 = 2  =>  0 pairs (X)
F4,E6: 2.. / F4 = 2  =>  0 pairs (X) / E6 = 2  => 19 pairs (_)
E8,F9: 2.. / E8 = 2  =>  0 pairs (X) / F9 = 2  => 19 pairs (_)
G8,G9: 2.. / G8 = 2  => 19 pairs (_) / G9 = 2  =>  0 pairs (X)
C4,F4: 2.. / C4 = 2  => 19 pairs (_) / F4 = 2  =>  0 pairs (X)
C6,E6: 2.. / C6 = 2  =>  0 pairs (X) / E6 = 2  => 19 pairs (_)
E8,G8: 2.. / E8 = 2  =>  0 pairs (X) / G8 = 2  => 19 pairs (_)
F9,G9: 2.. / F9 = 2  => 19 pairs (_) / G9 = 2  =>  0 pairs (X)
E6,E8: 2.. / E6 = 2  => 19 pairs (_) / E8 = 2  =>  0 pairs (X)
F4,F9: 2.. / F4 = 2  =>  0 pairs (X) / F9 = 2  => 19 pairs (_)
H2,I2: 3.. / H2 = 3  => 25 pairs (_) / I2 = 3  => 31 pairs (_)
A5,A6: 3.. / A5 = 3  => 29 pairs (_) / A6 = 3  =>  0 pairs (X)
D7,D8: 3.. / D7 = 3  =>  0 pairs (X) / D8 = 3  => 23 pairs (_)
A5,G5: 3.. / A5 = 3  => 29 pairs (_) / G5 = 3  =>  0 pairs (X)
A5,A6: 4.. / A5 = 4  =>  0 pairs (X) / A6 = 4  => 29 pairs (_)
E5,F6: 4.. / E5 = 4  => 29 pairs (_) / F6 = 4  =>  0 pairs (X)
B7,B8: 4.. / B7 = 4  => 25 pairs (_) / B8 = 4  => 25 pairs (_)
C3,D3: 4.. / C3 = 4  =>  0 pairs (X) / D3 = 4  => 29 pairs (_)
A5,E5: 4.. / A5 = 4  =>  0 pairs (X) / E5 = 4  => 29 pairs (_)
A6,F6: 4.. / A6 = 4  => 29 pairs (_) / F6 = 4  =>  0 pairs (X)
D3,D9: 4.. / D3 = 4  => 29 pairs (_) / D9 = 4  =>  0 pairs (X)
E3,F3: 6.. / E3 = 6  => 19 pairs (_) / F3 = 6  =>  0 pairs (X)
C4,C6: 6.. / C4 = 6  =>  0 pairs (X) / C6 = 6  => 19 pairs (_)
E7,F7: 6.. / E7 = 6  =>  0 pairs (X) / F7 = 6  => 19 pairs (_)
H9,I9: 6.. / H9 = 6  => 26 pairs (_) / I9 = 6  => 27 pairs (_)
E3,E7: 6.. / E3 = 6  => 19 pairs (_) / E7 = 6  =>  0 pairs (X)
F3,F7: 6.. / F3 = 6  =>  0 pairs (X) / F7 = 6  => 19 pairs (_)
F4,E6: 7.. / F4 = 7  => 19 pairs (_) / E6 = 7  =>  0 pairs (X)
H4,H6: 7.. / H4 = 7  =>  0 pairs (X) / H6 = 7  => 19 pairs (_)
E7,F9: 7.. / E7 = 7  => 19 pairs (_) / F9 = 7  =>  0 pairs (X)
G7,G9: 7.. / G7 = 7  =>  0 pairs (X) / G9 = 7  => 19 pairs (_)
F4,H4: 7.. / F4 = 7  => 19 pairs (_) / H4 = 7  =>  0 pairs (X)
E6,H6: 7.. / E6 = 7  =>  0 pairs (X) / H6 = 7  => 19 pairs (_)
E7,G7: 7.. / E7 = 7  => 19 pairs (_) / G7 = 7  =>  0 pairs (X)
F9,G9: 7.. / F9 = 7  =>  0 pairs (X) / G9 = 7  => 19 pairs (_)
E6,E7: 7.. / E6 = 7  =>  0 pairs (X) / E7 = 7  => 19 pairs (_)
F4,F9: 7.. / F4 = 7  => 19 pairs (_) / F9 = 7  =>  0 pairs (X)
C1,C2: 8.. / C1 = 8  => 26 pairs (_) / C2 = 8  => 26 pairs (_)
E1,E2: 8.. / E1 = 8  => 26 pairs (_) / E2 = 8  => 26 pairs (_)
H4,I4: 8.. / H4 = 8  =>  0 pairs (X) / I4 = 8  => 23 pairs (_)
D7,D8: 8.. / D7 = 8  => 23 pairs (_) / D8 = 8  =>  0 pairs (X)
I7,H8: 8.. / I7 = 8  =>  0 pairs (X) / H8 = 8  => 23 pairs (_)
C1,E1: 8.. / C1 = 8  => 26 pairs (_) / E1 = 8  => 26 pairs (_)
C2,E2: 8.. / C2 = 8  => 26 pairs (_) / E2 = 8  => 26 pairs (_)
D7,I7: 8.. / D7 = 8  => 23 pairs (_) / I7 = 8  =>  0 pairs (X)
D8,H8: 8.. / D8 = 8  =>  0 pairs (X) / H8 = 8  => 23 pairs (_)
H4,H8: 8.. / H4 = 8  =>  0 pairs (X) / H8 = 8  => 23 pairs (_)
I4,I7: 8.. / I4 = 8  => 23 pairs (_) / I7 = 8  =>  0 pairs (X)
E5,F6: 9.. / E5 = 9  =>  0 pairs (X) / F6 = 9  => 29 pairs (_)
B7,B8: 9.. / B7 = 9  => 25 pairs (_) / B8 = 9  => 25 pairs (_)
C3,D3: 9.. / C3 = 9  => 29 pairs (_) / D3 = 9  =>  0 pairs (X)
E5,G5: 9.. / E5 = 9  =>  0 pairs (X) / G5 = 9  => 29 pairs (_)
D3,D9: 9.. / D3 = 9  =>  0 pairs (X) / D9 = 9  => 29 pairs (_)
* DURATION: 0:02:13.429696  START: 19:37:24.189233  END: 19:39:37.618929 2017-05-04
* CP COUNT: (57)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,B7,B8,C3,C4,C6,D3,D7,D8,D9,E3,E5,E6,E7,E8,F3,F4,F6,F9,G5,G9,H1,I4)
* 76.2.35.112.7.56..53....82795.13.4...716.8.52.8.5..1..2.5....1.6.7.....5813.5....
* PAIR C3: 4,9 BLK 1
C1: 4,9,8                                # reduction candidate for 4,9
C1: 4,9                                  # 26 pairs
C2: 4,9,8                                # reduction candidate for 4,9
C2: 4,9                                  # 26 pairs
* PAIR D3: 4,9 BLK 2
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 26 pairs
E2: 4,9,8                                # reduction candidate for 4,9
E2: 4,9                                  # 26 pairs
* PAIR H1: 4,9 BLK 3
H2: 4,9,3                                # reduction candidate for 4,9
H2: 4,9                                  # 31 pairs
I2: 4,9,3                                # reduction candidate for 4,9
I2: 4,9                                  # 25 pairs
* PAIR H1: 4,9 ROW 1
C1: 4,9,8                                # reduction candidate for 4,9
C1: 4,9                                  # 26 pairs
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 26 pairs
* PAIR H1: 4,9 COL H
H8: 4,9,3,8                              # reduction candidate for 4,9
H8: 4,9 => CTR
* 76.2.35.112.7.56..53....82795.13.486.716.8.52.8652.17.2.5.76.186.781...5813.5....
H8: 3,8                                  # 26 pairs
H9: 4,9,6                                # reduction candidate for 4,9
H9: 4,9                                  # 27 pairs
* PAIR E5: 4,9 COL E
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 26 pairs
E2: 4,9,8                                # reduction candidate for 4,9
E2: 4,9                                  # 26 pairs
* PAIR F6: 4,9 COL F
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 76.2.35.112.7.563.539416827956132478.716.8.52.8257.1..2.586.7136.73219858139572..
F7: 6                                    # 19 pairs
F8: 4,9,1                                # reduction candidate for 4,9
F8: 4,9                                  # 19 pairs
* PAIR I4: 6,8 BLK 6
H4: 6,8,7                                # reduction candidate for 6,8
H4: 7 => CTR
* 76.2.35.112.7.563.53941.82795.13.478.716.8.52.8.57.1..2.586.7136.73219858139572..
H4: 6,8                                  # 19 pairs
* PAIR G5: 3,9 BLK 6
H6: 3,9,6,7                              # reduction candidate for 3,9
H6: 3,9 => CTR
* 76.2.35.112.7.563953941.82795.13.478.716.8.52.8.57.1.62.586.7136.7321985813957264
H6: 6,7                                  # 26 pairs
I6: 3,9,6                                # reduction candidate for 3,9
I6: 3,9                                  # 26 pairs
* PAIR G5: 3,9 COL G
G7: 3,9,7                                # reduction candidate for 3,9
G7: 3,9                                  # 19 pairs
G8: 3,9,2                                # reduction candidate for 3,9
G8: 3,9 => CTR
* 76.2.35.112.7.563.539416827956132478.716.8.52.8257.1..2.586.7136.73219858139572..
G8: 2                                    # 19 pairs
* PAIR B7: 4,9 ROW 7
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 76.2.35.112.7.563.539416827956132478.716.8.52.8257.1..2.586.7136.73219858139572..
F7: 6                                    # 19 pairs
I7: 4,9,3,8                              # reduction candidate for 4,9
I7: 4,9 => SOLVED
* 764283591128795634539461827952137468371648952486529173245876319697314285813952746
I7: 3,8                                  # 26 pairs
* PAIR B8: 4,9 ROW 8
F8: 4,9,1                                # reduction candidate for 4,9
F8: 4,9                                  # 19 pairs
H8: 4,9,3,8                              # reduction candidate for 4,9
H8: 4,9 => CTR
* 76.2.35.112.7.56..53....82795.13.486.716.8.52.8652.17.2.5.76.186.781...5813.5....
H8: 3,8                                  # 26 pairs
* PAIR D7: 3,8 ROW 7
I7: 3,8,4,9                              # reduction candidate for 3,8
I7: 4,9 => SOLVED
* 764283591128795634539461827952137468371648952486529173245876319697314285813952746
I7: 3,8                                  # 26 pairs
* PAIR D8: 3,8 ROW 8
H8: 3,8,4,9                              # reduction candidate for 3,8
H8: 4,9 => CTR
* 76.2.35.112.7.56..53....82795.13.486.716.8.52.8652.17.2.5.76.186.781...5813.5....
H8: 3,8                                  # 26 pairs
* PAIR D9: 4,9 BLK 8
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 76.2.35.112.7.563.539416827956132478.716.8.52.8257.1..2.586.7136.73219858139572..
F7: 6                                    # 19 pairs
F8: 4,9,1                                # reduction candidate for 4,9
F8: 4,9                                  # 19 pairs
* PAIR D9: 4,9 ROW 9
H9: 4,9,6                                # reduction candidate for 4,9
H9: 4,9                                  # 27 pairs
I9: 4,9,6                                # reduction candidate for 4,9
I9: 4,9                                  # 26 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-496-base-pr-000.dot
* REASONING
* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS # F7: 4,9 => CTR => F7: 6
* DIS # H4: 7 => CTR => H4: 6,8
* DIS # H6: 3,9 => CTR => H6: 6,7
* DIS # G8: 3,9 => CTR => G8: 2
* DIS # F7: 4,9 => CTR => F7: 6
* PRF # I7: 4,9 => SOL
* DIS # H8: 4,9 => CTR => H8: 3,8
* PRF # I7: 4,9 => SOL
* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS # F7: 4,9 => CTR => F7: 6
* CNT  11 HDP CHAINS /  40 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,B7,B8,C3,C4,C6,D3,D7,D8,D9,E3,E5,E6,E7,E8,F3,F4,F6,F9,G5,G9,H1,I4)
* 76.2.35.112.7.56..53....82795.13.4...716.8.52.8.5..1..2.5....1.6.7.....5813.5....
* PAIR C3: 4,9 BLK 1
C1: 4,9,8                                # reduction candidate for 4,9
C1: 4,9                                  # 26 pairs
C2: 4,9,8                                # reduction candidate for 4,9
C2: 4,9                                  # 26 pairs
* PAIR D3: 4,9 BLK 2
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 26 pairs
E2: 4,9,8                                # reduction candidate for 4,9
E2: 4,9                                  # 26 pairs
* PAIR H1: 4,9 BLK 3
H2: 4,9,3                                # reduction candidate for 4,9
H2: 4,9                                  # 31 pairs
I2: 4,9,3                                # reduction candidate for 4,9
I2: 4,9                                  # 25 pairs
* PAIR H1: 4,9 ROW 1
C1: 4,9,8                                # reduction candidate for 4,9
C1: 4,9                                  # 26 pairs
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 26 pairs
* PAIR H1: 4,9 COL H
H8: 4,9,3,8                              # reduction candidate for 4,9
H8: 4,9 => CTR
* 76.2.35.112.7.56..53....82795.13.486.716.8.52.8652.17.2.5.76.186.781...5813.5....
H9: 4,9,6                                # reduction candidate for 4,9
H9: 4,9                                  # 27 pairs
* RESTART
* PAIR H1: 4,9 COL H
H9: 4,9,6                                # reduction candidate for 4,9
H9: 6                                    # 29 pairs
H9: 4,9                                  # 27 pairs
* PAIR RESTART
* PAIR H1: 4,9 BLK 3
H2: 4,9,3                                # reduction candidate for 4,9
H2: 4,9                                  # 31 pairs
I2: 4,9,3                                # reduction candidate for 4,9
I2: 4,9                                  # 24 pairs
* PAIR H1: 4,9 ROW 1
C1: 4,9,8                                # reduction candidate for 4,9
C1: 4,9                                  # 28 pairs
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 28 pairs
* PAIR H1: 4,9 COL H
H9: 4,9,6                                # reduction candidate for 4,9
H9: 6                                    # 29 pairs
H9: 4,9                                  # 27 pairs
* PAIR E5: 4,9 COL E
E1: 4,9,8                                # reduction candidate for 4,9
E1: 4,9                                  # 28 pairs
E2: 4,9,8                                # reduction candidate for 4,9
E2: 4,9                                  # 28 pairs
* PAIR F6: 4,9 COL F
F7: 4,9,6                                # reduction candidate for 4,9
F7: 4,9 => CTR
* 76.2.35.112.7.56..53..1682795.132478.716.83523825741..2.58697136.7..1..5813.572..
* RESTART
* PAIR RESTART
* PAIR B7: 4,9 ROW 7
I7: 4,9,3,8                              # reduction candidate for 4,9
I7: 4,9 => SOLVED
* 764283591128795634539461827952137468371648952486529173245876319697314285813952746
* DURATION: 0:00:27.337969  START: 19:40:26.220146  END: 19:40:53.558115 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-496-base-pr-001.dot
* REASONING
* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS H8: 3,8 # F7: 4,9 => CTR => F7: 6
* PRF H8: 3,8 + F7: 6 # I7: 4,9 => SOL
* STA H8: 3,8 + F7: 6 + I7: 4,9
* CNT   3 HDP CHAINS /  22 HYP OPENED

Header Info

Top 500 Minimum 17 496

solution: 764283591128795634539461827952137468371648952486529173245876319697314285813952746
info: 96455    FNBTHXK  S8.f     7669

http://www.sfsudoku.com/su17ExtremeDiff500.txt from http://www.minimumsudoku.com/

Solution

position: 764283591128795634539461827952137468371648952486529173245876319697314285813952746 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 # C1: 4,9 => UNS
* INC # C2: 4,9 => UNS
* INC # E1: 4,9 => UNS
* INC # E2: 4,9 => UNS
* INC # H2: 4,9 => UNS
* INC # I2: 4,9 => UNS
* INC # C1: 4,9 => UNS
* INC # E1: 4,9 => UNS
* DIS # H8: 4,9 => CTR => H8: 3,8
* INC # H8: 3,8 => UNS
* INC # H9: 4,9 => UNS
* INC # E1: 4,9 => UNS
* INC # E2: 4,9 => UNS
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* INC # F8: 4,9 => UNS
* INC # H4: 6,8 => UNS
* DIS # H4: 7 => CTR => H4: 6,8
* DIS # H6: 3,9 => CTR => H6: 6,7
* INC # H6: 6,7 => UNS
* INC # I6: 3,9 => UNS
* INC # G7: 3,9 => UNS
* DIS # G8: 3,9 => CTR => G8: 2
* INC # G8: 2 => UNS
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* PRF # I7: 4,9 => SOL
* INC # I7: 3,8 => UNS
* INC # F8: 4,9 => UNS
* DIS # H8: 4,9 => CTR => H8: 3,8
* INC # H8: 3,8 => UNS
* INC # I7: 3,8 => UNS
* PRF # I7: 4,9 => SOL
* INC # H8: 3,8 => UNS
* DIS # H8: 4,9 => CTR => H8: 3,8
* DIS # F7: 4,9 => CTR => F7: 6
* INC # F7: 6 => UNS
* INC # F8: 4,9 => UNS
* INC # H9: 4,9 => UNS
* INC # I9: 4,9 => UNS
* CNT  40 HDP CHAINS /  40 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C1: 4,9 => UNS
* INC # C2: 4,9 => UNS
* INC # E1: 4,9 => UNS
* INC # E2: 4,9 => UNS
* INC # H2: 4,9 => UNS
* INC # I2: 4,9 => UNS
* INC # C1: 4,9 => UNS
* INC # E1: 4,9 => UNS
* DIS # H8: 4,9 => CTR => H8: 3,8
* INC H8: 3,8 # H9: 4,9 => UNS
* INC H8: 3,8 # H9: 4,9 => UNS
* INC H8: 3,8 # H9: 6 => UNS
* INC H8: 3,8 # H2: 4,9 => UNS
* INC H8: 3,8 # I2: 4,9 => UNS
* INC H8: 3,8 # C1: 4,9 => UNS
* INC H8: 3,8 # E1: 4,9 => UNS
* INC H8: 3,8 # H9: 4,9 => UNS
* INC H8: 3,8 # H9: 6 => UNS
* INC H8: 3,8 # E1: 4,9 => UNS
* INC H8: 3,8 # E2: 4,9 => UNS
* DIS H8: 3,8 # F7: 4,9 => CTR => F7: 6
* PRF H8: 3,8 + F7: 6 # I7: 4,9 => SOL
* STA H8: 3,8 + F7: 6 + I7: 4,9
* CNT  22 HDP CHAINS /  22 HYP OPENED