Analysis of xx-top500-497-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .....87..2...1....1.4.........26.3...5....6..8.........3.6........4...2........1. initial

Autosolve

position: ....287412...14.6.1.4..623....26.3...5.18.6..8...4.1...3.6........4...2....8...1. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A1: 6,9 => CTR => A1: 3,5
* DIS # B6: 6,9 => CTR => B6: 2,7
* DIS # B8: 6,9 => CTR => B8: 1,7,8
* DIS # B9: 6,9 => CTR => B9: 2,4,7
* DIS # H4: 7,9 => CTR => H4: 5,8
* DIS # I4: 7,9 => CTR => I4: 4,5,8
* DIS # I5: 7,9 => CTR => I5: 2,4
* PRF # I6: 7,9 => SOL
* DIS # A5: 7,9 => CTR => A5: 3,4
* DIS # C5: 7,9 => CTR => C5: 2,3
* PRF # F8: 5,9 => SOL
* DIS # F9: 5,9 => CTR => F9: 2,7
* DIS # G7: 5,9 => CTR => G7: 4,8
* DIS # H7: 5,9 => CTR => H7: 7,8
* DIS # I7: 5,9 => CTR => I7: 7,8
* DIS # G7: 5,9 => CTR => G7: 4,8
* DIS # H7: 5,9 => CTR => H7: 7,8
* DIS # I7: 5,9 => CTR => I7: 7,8
* DIS # C8: 5,9 => CTR => C8: 1,6,7,8
* PRF # F8: 5,9 => SOL
* DIS # G2: 5,9 => CTR => G2: 8
* CNT  21 HDP CHAINS /  55 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 # A1: 6,9 => CTR => A1: 3,5
* DIS A1: 3,5 # B6: 6,9 => CTR => B6: 2,7
* PRF A1: 3,5 + B6: 2,7 # I6: 7,9 => SOL
* STA A1: 3,5 + B6: 2,7 + I6: 7,9
* CNT   3 HDP CHAINS /   7 HYP OPENED

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

Details

Positions

.....87..2...1....1.4.........26.3...5....6..8.........3.6........4...2........1. initial
....287412...14.6.1.4..623....26.3...5.18.6..8...4.1...3.6........4...2....8...1. autosolve
369528741275314869184796235791265384453187692826943157932651478618479523547832916 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
B1: 6,9
H5: 7,9
C7: 1,2
E7: 5,9
F7: 1,2
G8: 5,9
I8: 3,6
I9: 3,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B4,C4: 1.. / B4 = 1  =>  0 pairs (X) / C4 = 1  =>  0 pairs (_)
F7,F8: 1.. / F7 = 1  =>  0 pairs (*) / F8 = 1  =>  0 pairs (X)
C7,F7: 1.. / C7 = 1  =>  0 pairs (X) / F7 = 1  =>  0 pairs (_)
B4,B8: 1.. / B4 = 1  =>  0 pairs (X) / B8 = 1  =>  0 pairs (_)
I5,I6: 2.. / I5 = 2  =>  0 pairs (*) / I6 = 2  =>  0 pairs (X)
F7,F9: 2.. / F7 = 2  =>  0 pairs (X) / F9 = 2  =>  0 pairs (_)
C5,I5: 2.. / C5 = 2  =>  0 pairs (X) / I5 = 2  =>  0 pairs (_)
C7,F7: 2.. / C7 = 2  =>  0 pairs (*) / F7 = 2  =>  0 pairs (X)
B6,B9: 2.. / B6 = 2  =>  0 pairs (*) / B9 = 2  =>  0 pairs (X)
D1,D2: 3.. / D1 = 3  =>  0 pairs (X) / D2 = 3  => 10 pairs (_)
F5,F6: 3.. / F5 = 3  =>  0 pairs (X) / F6 = 3  => 12 pairs (_)
E8,E9: 3.. / E8 = 3  =>  6 pairs (_) / E9 = 3  =>  6 pairs (_)
I8,I9: 3.. / I8 = 3  =>  6 pairs (_) / I9 = 3  =>  6 pairs (_)
C2,D2: 3.. / C2 = 3  =>  0 pairs (X) / D2 = 3  => 10 pairs (_)
C6,F6: 3.. / C6 = 3  =>  0 pairs (X) / F6 = 3  => 12 pairs (_)
E8,I8: 3.. / E8 = 3  =>  6 pairs (_) / I8 = 3  =>  6 pairs (_)
E9,I9: 3.. / E9 = 3  =>  6 pairs (_) / I9 = 3  =>  6 pairs (_)
A1,A5: 3.. / A1 = 3  => 12 pairs (_) / A5 = 3  =>  0 pairs (X)
I4,I5: 4.. / I4 = 4  =>  0 pairs (*) / I5 = 4  =>  0 pairs (X)
G7,G9: 4.. / G7 = 4  => 16 pairs (_) / G9 = 4  =>  0 pairs (X)
A5,I5: 4.. / A5 = 4  =>  0 pairs (*) / I5 = 4  =>  0 pairs (X)
A7,G7: 4.. / A7 = 4  =>  0 pairs (X) / G7 = 4  => 16 pairs (_)
B4,B9: 4.. / B4 = 4  =>  0 pairs (X) / B9 = 4  =>  0 pairs (_)
B6,C6: 6.. / B6 = 6  =>  0 pairs (X) / C6 = 6  => 12 pairs (_)
I8,I9: 6.. / I8 = 6  =>  6 pairs (_) / I9 = 6  =>  6 pairs (_)
H7,I7: 7.. / H7 = 7  => 12 pairs (_) / I7 = 7  =>  8 pairs (_)
H4,I4: 8.. / H4 = 8  =>  8 pairs (_) / I4 = 8  =>  0 pairs (X)
B8,C8: 8.. / B8 = 8  =>  0 pairs (X) / C8 = 8  =>  8 pairs (_)
B3,I3: 8.. / B3 = 8  => 10 pairs (_) / I3 = 8  =>  0 pairs (X)
C2,C8: 8.. / C2 = 8  =>  0 pairs (X) / C8 = 8  =>  8 pairs (_)
G2,G7: 8.. / G2 = 8  => 14 pairs (_) / G7 = 8  =>  0 pairs (X)
H4,H7: 8.. / H4 = 8  =>  8 pairs (_) / H7 = 8  =>  0 pairs (X)
* DURATION: 0:00:54.133842  START: 19:41:09.511211  END: 19:42:03.645053 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,C7,E7,F7,G8,H5,I8,I9)
* ....287412...14.6.1.4..623....26.3...5.18.6..8...4.1...3.6........4...2....8...1.
* PAIR B1: 6,9 BLK 1
A1: 6,9,3,5                              # reduction candidate for 6,9
A1: 6,9 => CTR
* ....287412...14.6.1.4..623..4126.3..35.18.6.48...431.2.3.6........4...2..2.8...1.
A1: 3,5                                  #  9 pairs
C1: 6,9,3,5                              # reduction candidate for 6,9
C1: 6,9                                  # 15 pairs
* PAIR B1: 6,9 COL B
B6: 6,9,2,7                              # reduction candidate for 6,9
B6: 6,9 => CTR
* ....287412...14.6.1.4..623..4126.3...5.18.6..8...4.1...3.6........4...2..2.8...1.
B6: 2,7                                  # 14 pairs
B8: 6,9,1,7,8                            # reduction candidate for 6,9
B8: 6,9 => CTR
* 36..2874127.31486.1847.623.91726538445318.6.2826.431.7.316.2478.984.152..428..91.
B8: 1,7,8                                #  8 pairs
B9: 6,9,2,4,7                            # reduction candidate for 6,9
B9: 6,9 => CTR
* ....287412...14.6.1.4..623..4126.3...5.18.6.4826.431...326.1....184...2....8.2.1.
B9: 2,4,7                                #  8 pairs
* PAIR H5: 7,9 BLK 6
H4: 7,9,5,8                              # reduction candidate for 7,9
H4: 7,9 => CTR
* ....287412...1486.184..623..4126.3.8.5.18.6.48...4.1.2.3.6...87...4...2..2.8...1.
H4: 5,8                                  #  9 pairs
I4: 7,9,4,5,8                            # reduction candidate for 7,9
I4: 7,9 => CTR
* ....287412...14.6.1.4..623..4126.38..5.18.6.48...4.1.2.3.6........4...2..2.8...1.
I4: 4,5,8                                #  8 pairs
I5: 7,9,2,4                              # reduction candidate for 7,9
I5: 7,9 => CTR
* ....287412...14.6.1.4..623....26.3.44521836..8.3.4.1.2.316........4...2....8...1.
I5: 2,4                                  #  9 pairs
H6: 7,9,5                                # reduction candidate for 7,9
H6: 7,9                                  # 14 pairs
I6: 7,9,2,5                              # reduction candidate for 7,9
I6: 7,9 => SOLVED
* 369528741275314869184796235791265384453187692826943157932651478618479523547832916
I6: 2,5                                  #  9 pairs
* PAIR H5: 7,9 ROW 5
A5: 7,9,3,4                              # reduction candidate for 7,9
A5: 7,9 => CTR
* 3...287412..314.6.1.4..623..4126.3...5.18.6.48...4.1.2.3.6........4...2..2.8...1.
A5: 3,4                                  #  9 pairs
C5: 7,9,2,3                              # reduction candidate for 7,9
C5: 7,9 => CTR
* ....287412...14.6.1.4..623....26.3.445.1836.28.3.4.1...3.6..4.....4...2..4.8...1.
C5: 2,3                                  #  9 pairs
F5: 7,9,3                                # reduction candidate for 7,9
F5: 7,9                                  # 12 pairs
* PAIR H5: 7,9 COL H
H7: 7,9,5,8                              # reduction candidate for 7,9
H7: 5,8                                  # 12 pairs
H7: 7,9                                  # 11 pairs
* PAIR E7: 5,9 BLK 8
E8: 5,9,3,7                              # reduction candidate for 5,9
E8: 5,9                                  # 15 pairs
F8: 5,9,1,7                              # reduction candidate for 5,9
F8: 5,9 => SOLVED
* 369528741275314869184796235791265384453187692826943157932651478618479523547832916
F8: 1,7                                  #  9 pairs
E9: 5,9,3,7                              # reduction candidate for 5,9
E9: 5,9                                  # 14 pairs
F9: 5,9,2,7                              # reduction candidate for 5,9
F9: 5,9 => CTR
* 3695287412753148691847962359172653844531876928269431575316.2478..84.1.2..428.951.
F9: 2,7                                  #  9 pairs
* PAIR E7: 5,9 ROW 7
A7: 5,9,4                                # reduction candidate for 5,9
A7: 5,9                                  # 16 pairs
G7: 5,9,4,8                              # reduction candidate for 5,9
G7: 5,9 => CTR
* ....287412...1486.184..623..4126.3...5.18.6.48...4.1.24326.1....184...2....8.241.
G7: 4,8                                  #  9 pairs
H7: 5,9,7,8                              # reduction candidate for 5,9
H7: 5,9 => CTR
* ....287412...14.6.1.4..623..4126.38..5.18.6.48...4.1.24326.18.7.184...2....8.241.
H7: 7,8                                  # 10 pairs
I7: 5,9,7,8                              # reduction candidate for 5,9
I7: 5,9 => CTR
* ....287412...14.6.1.4..623..41265387.5.18.6948...4.1524326.187..184...2....8.241.
I7: 7,8                                  #  9 pairs
* PAIR E7: 5,9 COL E
E3: 5,9,7                                # reduction candidate for 5,9
E3: 7                                    # 15 pairs
E3: 5,9                                  # 12 pairs
* PAIR G8: 5,9 BLK 9
G7: 5,9,4,8                              # reduction candidate for 5,9
G7: 5,9 => CTR
* ....287412...1486.184..623..4126.3...5.18.6.48...4.1.24326.1....184...2....8.241.
G7: 4,8                                  #  9 pairs
H7: 5,9,7,8                              # reduction candidate for 5,9
H7: 5,9 => CTR
* ....287412...14.6.1.4..623..4126.38..5.18.6.48...4.1.24326.18.7.184...2....8.241.
H7: 7,8                                  # 10 pairs
I7: 5,9,7,8                              # reduction candidate for 5,9
I7: 5,9 => CTR
* ....287412...14.6.1.4..623..41265387.5.18.6948...4.1524326.187..184...2....8.241.
I7: 7,8                                  #  9 pairs
G9: 5,9,4                                # reduction candidate for 5,9
G9: 5,9                                  # 16 pairs
* PAIR G8: 5,9 ROW 8
A8: 5,9,6,7                              # reduction candidate for 5,9
A8: 5,9                                  # 11 pairs
C8: 5,9,1,6,7,8                          # reduction candidate for 5,9
C8: 5,9 => CTR
* ....287412.8314.6.1.4..6238...26.38..5.18.6..8...4.1...3.6..8...8.4.1.2....8..41.
C8: 1,6,7,8                              #  8 pairs
E8: 5,9,3,7                              # reduction candidate for 5,9
E8: 5,9                                  # 15 pairs
F8: 5,9,1,7                              # reduction candidate for 5,9
F8: 5,9 => SOLVED
* 369528741275314869184796235791265384453187692826943157932651478618479523547832916
F8: 1,7                                  #  9 pairs
* PAIR G8: 5,9 COL G
G2: 5,9,8                                # reduction candidate for 5,9
G2: 5,9 => CTR
* ....287412...14.6.1.4..623..4126.38..5.18.6.48...4.1.24326.18...184...2....8.241.
G2: 8                                    # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-497-base-pr-000.dot
* REASONING
* DIS # A1: 6,9 => CTR => A1: 3,5
* DIS # B6: 6,9 => CTR => B6: 2,7
* DIS # B8: 6,9 => CTR => B8: 1,7,8
* DIS # B9: 6,9 => CTR => B9: 2,4,7
* DIS # H4: 7,9 => CTR => H4: 5,8
* DIS # I4: 7,9 => CTR => I4: 4,5,8
* DIS # I5: 7,9 => CTR => I5: 2,4
* PRF # I6: 7,9 => SOL
* DIS # A5: 7,9 => CTR => A5: 3,4
* DIS # C5: 7,9 => CTR => C5: 2,3
* PRF # F8: 5,9 => SOL
* DIS # F9: 5,9 => CTR => F9: 2,7
* DIS # G7: 5,9 => CTR => G7: 4,8
* DIS # H7: 5,9 => CTR => H7: 7,8
* DIS # I7: 5,9 => CTR => I7: 7,8
* DIS # G7: 5,9 => CTR => G7: 4,8
* DIS # H7: 5,9 => CTR => H7: 7,8
* DIS # I7: 5,9 => CTR => I7: 7,8
* DIS # C8: 5,9 => CTR => C8: 1,6,7,8
* PRF # F8: 5,9 => SOL
* DIS # G2: 5,9 => CTR => G2: 8
* CNT  21 HDP CHAINS /  55 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,C7,E7,F7,G8,H5,I8,I9)
* ....287412...14.6.1.4..623....26.3...5.18.6..8...4.1...3.6........4...2....8...1.
* PAIR B1: 6,9 BLK 1
A1: 6,9,3,5                              # reduction candidate for 6,9
A1: 6,9 => CTR
* ....287412...14.6.1.4..623..4126.3..35.18.6.48...431.2.3.6........4...2..2.8...1.
C1: 6,9,3,5                              # reduction candidate for 6,9
C1: 6,9                                  # 15 pairs
* RESTART
* PAIR B1: 6,9 BLK 1
C1: 6,9,3,5                              # reduction candidate for 6,9
C1: 3,5                                  # 18 pairs
C1: 6,9                                  # 15 pairs
* PAIR B1: 6,9 COL B
B6: 6,9,2,7                              # reduction candidate for 6,9
B6: 6,9 => CTR
* ....287412...14.6.1.4..623..4126.3...5.18.6..8...4.1...3.6........4...2..2.8...1.
* PAIR RESTART
* PAIR H5: 7,9 BLK 6
H6: 7,9,5                                # reduction candidate for 7,9
H6: 7,9                                  # 19 pairs
I6: 7,9,2,5                              # reduction candidate for 7,9
I6: 7,9 => SOLVED
* 369528741275314869184796235791265384453187692826943157932651478618479523547832916
* DURATION: 0:00:09.620163  START: 19:42:51.086016  END: 19:43:00.706179 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-497-base-pr-001.dot
* REASONING
* DIS # A1: 6,9 => CTR => A1: 3,5
* DIS A1: 3,5 # B6: 6,9 => CTR => B6: 2,7
* PRF A1: 3,5 + B6: 2,7 # I6: 7,9 => SOL
* STA A1: 3,5 + B6: 2,7 + I6: 7,9
* CNT   3 HDP CHAINS /   7 HYP OPENED

Header Info

Top 500 Minimum 17 497

solution: 369528741275314869184796235791265384453187692826943157932651478618479523547832916
info: 96592    FNBHYK   S8.f     2530

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

Solution

position: 369528741275314869184796235791265384453187692826943157932651478618479523547832916 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 # A1: 6,9 => CTR => A1: 3,5
* INC # A1: 3,5 => UNS
* INC # C1: 6,9 => UNS
* DIS # B6: 6,9 => CTR => B6: 2,7
* INC # B6: 2,7 => UNS
* DIS # B8: 6,9 => CTR => B8: 1,7,8
* INC # B8: 1,7,8 => UNS
* DIS # B9: 6,9 => CTR => B9: 2,4,7
* INC # B9: 2,4,7 => UNS
* DIS # H4: 7,9 => CTR => H4: 5,8
* INC # H4: 5,8 => UNS
* DIS # I4: 7,9 => CTR => I4: 4,5,8
* INC # I4: 4,5,8 => UNS
* DIS # I5: 7,9 => CTR => I5: 2,4
* INC # I5: 2,4 => UNS
* INC # H6: 7,9 => UNS
* PRF # I6: 7,9 => SOL
* INC # I6: 2,5 => UNS
* DIS # A5: 7,9 => CTR => A5: 3,4
* INC # A5: 3,4 => UNS
* DIS # C5: 7,9 => CTR => C5: 2,3
* INC # C5: 2,3 => UNS
* INC # F5: 7,9 => UNS
* INC # H7: 7,9 => UNS
* INC # H7: 5,8 => UNS
* INC # E8: 5,9 => UNS
* PRF # F8: 5,9 => SOL
* INC # F8: 1,7 => UNS
* INC # E9: 5,9 => UNS
* DIS # F9: 5,9 => CTR => F9: 2,7
* INC # F9: 2,7 => UNS
* INC # A7: 5,9 => UNS
* DIS # G7: 5,9 => CTR => G7: 4,8
* INC # G7: 4,8 => UNS
* DIS # H7: 5,9 => CTR => H7: 7,8
* INC # H7: 7,8 => UNS
* DIS # I7: 5,9 => CTR => I7: 7,8
* INC # I7: 7,8 => UNS
* INC # E3: 5,9 => UNS
* INC # E3: 7 => UNS
* DIS # G7: 5,9 => CTR => G7: 4,8
* INC # G7: 4,8 => UNS
* DIS # H7: 5,9 => CTR => H7: 7,8
* INC # H7: 7,8 => UNS
* DIS # I7: 5,9 => CTR => I7: 7,8
* INC # I7: 7,8 => UNS
* INC # G9: 5,9 => UNS
* INC # A8: 5,9 => UNS
* DIS # C8: 5,9 => CTR => C8: 1,6,7,8
* INC # C8: 1,6,7,8 => UNS
* INC # E8: 5,9 => UNS
* PRF # F8: 5,9 => SOL
* INC # F8: 1,7 => UNS
* DIS # G2: 5,9 => CTR => G2: 8
* INC # G2: 8 => UNS
* CNT  55 HDP CHAINS /  55 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A1: 6,9 => CTR => A1: 3,5
* INC A1: 3,5 # C1: 6,9 => UNS
* INC A1: 3,5 # C1: 6,9 => UNS
* INC A1: 3,5 # C1: 3,5 => UNS
* DIS A1: 3,5 # B6: 6,9 => CTR => B6: 2,7
* INC A1: 3,5 + B6: 2,7 # H6: 7,9 => UNS
* PRF A1: 3,5 + B6: 2,7 # I6: 7,9 => SOL
* STA A1: 3,5 + B6: 2,7 + I6: 7,9
* CNT   7 HDP CHAINS /   7 HYP OPENED