Analysis of xx-top500-153-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .6.3.2.....7...41........8..3.5..6......1..2.............6..3..8...2....1........ initial

Autosolve

position: 461382...2879..4133..1..286.325.86.16...13.2..1.2...3..2.6.13.88.3.2.16.1.683...2 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B5: 5,9 => CTR => B5: 4,7
* DIS # B9: 5,9 => CTR => B9: 4,7
* PRF # C5: 5,9 => SOL
* DIS # C6: 5,9 => CTR => C6: 4,8
* DIS # E6: 4,7 => CTR => E6: 6,9
* DIS # E7: 4,7 => CTR => E7: 5,9
* DIS # F6: 4,7 => CTR => F6: 6,9
* PRF # F8: 4,7 => SOL
* DIS # E4: 7,9 => CTR => E4: 4
* PRF # E4: 4 => SOL
* PRF # H4: 7,9 => SOL
* DIS # H4: 4 => CTR => H4: 7,9
* DIS # E6: 4,7 => CTR => E6: 6,9
* DIS # F6: 4,7 => CTR => F6: 6,9
* DIS # I5: 4,7 => CTR => I5: 5,9
* DIS # E7: 4,7 => CTR => E7: 5,9
* PRF # F8: 4,7 => SOL
* DIS # B8: 4,7 => CTR => B8: 5,9
* CNT  18 HDP CHAINS /  44 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 # B5: 5,9 => CTR => B5: 4,7
* DIS B5: 4,7 # B9: 5,9 => CTR => B9: 4,7
* PRF B5: 4,7 + B9: 4,7 # C5: 5,9 => SOL
* STA B5: 4,7 + B9: 4,7 + C5: 5,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.6.3.2.....7...41........8..3.5..6......1..2.............6..3..8...2....1........ initial
461382...2879..4133..1..286.325.86.16...13.2..1.2...3..2.6.13.88.3.2.16.1.683...2 autosolve
461382957287965413395174286732548691649713825518296734924651378853427169176839542 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
B3: 5,9
C3: 5,9
E2: 5,6
F2: 5,6
E3: 4,7
F3: 4,7
A4: 7,9
D5: 4,7
D8: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E3,F3: 4.. / E3 = 4  =>  0 pairs (X) / F3 = 4  =>  8 pairs (_)
E4,H4: 4.. / E4 = 4  =>  0 pairs (*) / H4 = 4  =>  0 pairs (X)
D5,D8: 4.. / D5 = 4  =>  0 pairs (X) / D8 = 4  =>  0 pairs (_)
B3,C3: 5.. / B3 = 5  =>  6 pairs (_) / C3 = 5  =>  8 pairs (_)
E2,F2: 5.. / E2 = 5  =>  7 pairs (_) / F2 = 5  => 11 pairs (_)
A6,A7: 5.. / A6 = 5  => 10 pairs (_) / A7 = 5  => 11 pairs (_)
E2,E7: 5.. / E2 = 5  =>  7 pairs (_) / E7 = 5  => 11 pairs (_)
E2,F2: 6.. / E2 = 6  => 11 pairs (_) / F2 = 6  =>  7 pairs (_)
E6,F6: 6.. / E6 = 6  =>  7 pairs (_) / F6 = 6  => 11 pairs (_)
E2,E6: 6.. / E2 = 6  => 11 pairs (_) / E6 = 6  =>  7 pairs (_)
F2,F6: 6.. / F2 = 6  =>  7 pairs (_) / F6 = 6  => 11 pairs (_)
E3,F3: 7.. / E3 = 7  =>  8 pairs (_) / F3 = 7  =>  0 pairs (X)
D5,D8: 7.. / D5 = 7  =>  0 pairs (*) / D8 = 7  =>  0 pairs (X)
C5,C6: 8.. / C5 = 8  =>  9 pairs (_) / C6 = 8  =>  0 pairs (*)
G5,G6: 8.. / G5 = 8  =>  0 pairs (*) / G6 = 8  =>  0 pairs (X)
C5,G5: 8.. / C5 = 8  =>  9 pairs (_) / G5 = 8  =>  0 pairs (*)
C6,G6: 8.. / C6 = 8  =>  0 pairs (*) / G6 = 8  =>  0 pairs (X)
B3,C3: 9.. / B3 = 9  =>  8 pairs (_) / C3 = 9  =>  6 pairs (_)
* DURATION: 0:00:31.259269  START: 07:58:59.841519  END: 07:59:31.100788 2017-05-04
* CP COUNT: (18)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B3,C3,D5,D8,E2,E3,F2,F3)
* 461382...2879..4133..1..286.325.86.16...13.2..1.2...3..2.6.13.88.3.2.16.1.683...2
* PAIR B3: 5,9 COL B
B5: 5,9,4,7                              # reduction candidate for 5,9
B5: 5,9 => CTR
* 461382...2879564133..1..286.325986416...13.2..1.26..3..2.64137884372.16.17683...2
B5: 4,7                                  # 11 pairs
B8: 5,9,4,7                              # reduction candidate for 5,9
B8: 5,9                                  # 13 pairs
B9: 5,9,4,7                              # reduction candidate for 5,9
B9: 5,9 => CTR
* 461382.572879..4133..1742867325486916497138255182..73492465137887342.16.1.6837.42
B9: 4,7                                  # 10 pairs
* PAIR C3: 5,9 COL C
C5: 5,9,4,8                              # reduction candidate for 5,9
C5: 5,9 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
C5: 4,8                                  # 10 pairs
C6: 5,9,4,8                              # reduction candidate for 5,9
C6: 5,9 => CTR
* 461382...2879..4133..174286.32548671648713.2.7152..8345246913.88.342.16.1.683..42
C6: 4,8                                  # 10 pairs
C7: 5,9,4                                # reduction candidate for 5,9
C7: 5,9                                  # 12 pairs
* PAIR E3: 4,7 COL E
E4: 4,7,9                                # reduction candidate for 4,7
E4: 4,7                                  # 14 pairs
E6: 4,7,6,9                              # reduction candidate for 4,7
E6: 4,7 => CTR
* 461382...2879654133.514728673259864164.713.2.51.2.6.3.9246513788.3.2.1641.6834..2
E6: 6,9                                  # 10 pairs
E7: 4,7,5,9                              # reduction candidate for 4,7
E7: 4,7 => CTR
* 461382...2879564133..1..2867325986416..413.2..1426783..2.6413788.372.1641.683...2
E7: 5,9                                  # 10 pairs
* PAIR F3: 4,7 COL F
F6: 4,7,6,9                              # reduction candidate for 4,7
F6: 4,7 => CTR
* 461382...2879564133..1..2867325986416..413.2..1426783..2.6413788.372.1641.683...2
F6: 6,9                                  # 10 pairs
F8: 4,7,5,9                              # reduction candidate for 4,7
F8: 4,7 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
F8: 5,9                                  # 10 pairs
F9: 4,7,5,9                              # reduction candidate for 4,7
F9: 4,7                                  # 13 pairs
* PAIR A4: 7,9 BLK 4
B5: 7,9,4,5                              # reduction candidate for 7,9
B5: 7,9                                  # 14 pairs
A6: 7,9,5                                # reduction candidate for 7,9
A6: 7,9                                  # 11 pairs
* PAIR A4: 7,9 ROW 4
E4: 7,9,4                                # reduction candidate for 7,9
E4: 7,9 => CTR
* 461382...2879564133..1742867325986416.8413.2..1426783..2.6413788.372.16414683...2
E4: 4 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
H4: 7,9,4                                # reduction candidate for 7,9
H4: 7,9 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
H4: 4 => CTR
* 461382...2879564133..1742867325986416.8413.2..1426783..2.6413788.372.16414683...2
* PAIR A4: 7,9 COL A
A7: 7,9,5                                # reduction candidate for 7,9
A7: 5                                    # 11 pairs
A7: 7,9                                  # 10 pairs
* PAIR D5: 4,7 BLK 5
E4: 4,7,9                                # reduction candidate for 4,7
E4: 4,7                                  # 14 pairs
E6: 4,7,6,9                              # reduction candidate for 4,7
E6: 4,7 => CTR
* 461382...2879654133.514728673259864164.713.2.51.2.6.3.9246513788.3.2.1641.6834..2
E6: 6,9                                  # 10 pairs
F6: 4,7,6,9                              # reduction candidate for 4,7
F6: 4,7 => CTR
* 461382...2879564133..1..2867325986416..413.2..1426783..2.6413788.372.1641.683...2
F6: 6,9                                  # 10 pairs
* PAIR D5: 4,7 ROW 5
B5: 4,7,5,9                              # reduction candidate for 4,7
B5: 4,7                                  # 11 pairs
I5: 4,7,5,9                              # reduction candidate for 4,7
I5: 4,7 => CTR
* 4613827..2879564133..1742867325986416.8413.27.1426783..2.64137884372.16.17683...2
I5: 5,9                                  # 10 pairs
* PAIR D8: 4,7 BLK 8
E7: 4,7,5,9                              # reduction candidate for 4,7
E7: 4,7 => CTR
* 461382...2879564133..1..2867325986416..413.2..1426783..2.6413788.372.1641.683...2
E7: 5,9                                  # 10 pairs
F8: 4,7,5,9                              # reduction candidate for 4,7
F8: 4,7 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
F8: 5,9                                  # 10 pairs
F9: 4,7,5,9                              # reduction candidate for 4,7
F9: 4,7                                  # 13 pairs
* PAIR D8: 4,7 ROW 8
B8: 4,7,5,9                              # reduction candidate for 4,7
B8: 4,7 => CTR
* 461382.5.2879..4133..1742867325486916497138255182..73492465137887342.16.1.6837.42
B8: 5,9                                  # 13 pairs
I8: 4,7,5,9                              # reduction candidate for 4,7
I8: 4,7                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-153-base-pr-000.dot
* REASONING
* DIS # B5: 5,9 => CTR => B5: 4,7
* DIS # B9: 5,9 => CTR => B9: 4,7
* PRF # C5: 5,9 => SOL
* DIS # C6: 5,9 => CTR => C6: 4,8
* DIS # E6: 4,7 => CTR => E6: 6,9
* DIS # E7: 4,7 => CTR => E7: 5,9
* DIS # F6: 4,7 => CTR => F6: 6,9
* PRF # F8: 4,7 => SOL
* DIS # E4: 7,9 => CTR => E4: 4
* PRF # E4: 4 => SOL
* PRF # H4: 7,9 => SOL
* DIS # H4: 4 => CTR => H4: 7,9
* DIS # E6: 4,7 => CTR => E6: 6,9
* DIS # F6: 4,7 => CTR => F6: 6,9
* DIS # I5: 4,7 => CTR => I5: 5,9
* DIS # E7: 4,7 => CTR => E7: 5,9
* PRF # F8: 4,7 => SOL
* DIS # B8: 4,7 => CTR => B8: 5,9
* CNT  18 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B3,C3,D5,D8,E2,E3,F2,F3)
* 461382...2879..4133..1..286.325.86.16...13.2..1.2...3..2.6.13.88.3.2.16.1.683...2
* PAIR B3: 5,9 COL B
B5: 5,9,4,7                              # reduction candidate for 5,9
B5: 5,9 => CTR
* 461382...2879564133..1..286.325986416...13.2..1.26..3..2.64137884372.16.17683...2
B8: 5,9,4,7                              # reduction candidate for 5,9
B8: 5,9                                  # 13 pairs
B9: 5,9,4,7                              # reduction candidate for 5,9
B9: 5,9 => CTR
* 461382.572879..4133..1742867325486916497138255182..73492465137887342.16.1.6837.42
* RESTART
* PAIR RESTART
* PAIR C3: 5,9 COL C
C5: 5,9,8                                # reduction candidate for 5,9
C5: 5,9 => SOLVED
* 461382957287965413395174286732548691649713825518296734924651378853427169176839542
* DURATION: 0:00:05.781023  START: 08:00:13.692181  END: 08:00:19.473204 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-153-base-pr-001.dot
* REASONING
* DIS # B5: 5,9 => CTR => B5: 4,7
* DIS B5: 4,7 # B9: 5,9 => CTR => B9: 4,7
* PRF B5: 4,7 + B9: 4,7 # C5: 5,9 => SOL
* STA B5: 4,7 + B9: 4,7 + C5: 5,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 153

solution: 461382957287965413395174286732548691649713825518296734924651378853427169176839542
info: 1817     FNBWXY   S8.f     21418

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

Solution

position: 461382957287965413395174286732548691649713825518296734924651378853427169176839542 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 # B5: 5,9 => CTR => B5: 4,7
* INC # B5: 4,7 => UNS
* INC # B8: 5,9 => UNS
* DIS # B9: 5,9 => CTR => B9: 4,7
* INC # B9: 4,7 => UNS
* PRF # C5: 5,9 => SOL
* INC # C5: 4,8 => UNS
* DIS # C6: 5,9 => CTR => C6: 4,8
* INC # C6: 4,8 => UNS
* INC # C7: 5,9 => UNS
* INC # E4: 4,7 => UNS
* DIS # E6: 4,7 => CTR => E6: 6,9
* INC # E6: 6,9 => UNS
* DIS # E7: 4,7 => CTR => E7: 5,9
* INC # E7: 5,9 => UNS
* DIS # F6: 4,7 => CTR => F6: 6,9
* INC # F6: 6,9 => UNS
* PRF # F8: 4,7 => SOL
* INC # F8: 5,9 => UNS
* INC # F9: 4,7 => UNS
* INC # B5: 7,9 => UNS
* INC # A6: 7,9 => UNS
* DIS # E4: 7,9 => CTR => E4: 4
* PRF # E4: 4 => SOL
* PRF # H4: 7,9 => SOL
* DIS # H4: 4 => CTR => H4: 7,9
* INC # A7: 7,9 => UNS
* INC # A7: 5 => UNS
* INC # E4: 4,7 => UNS
* DIS # E6: 4,7 => CTR => E6: 6,9
* INC # E6: 6,9 => UNS
* DIS # F6: 4,7 => CTR => F6: 6,9
* INC # F6: 6,9 => UNS
* INC # B5: 4,7 => UNS
* DIS # I5: 4,7 => CTR => I5: 5,9
* INC # I5: 5,9 => UNS
* DIS # E7: 4,7 => CTR => E7: 5,9
* INC # E7: 5,9 => UNS
* PRF # F8: 4,7 => SOL
* INC # F8: 5,9 => UNS
* INC # F9: 4,7 => UNS
* DIS # B8: 4,7 => CTR => B8: 5,9
* INC # B8: 5,9 => UNS
* INC # I8: 4,7 => UNS
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B5: 5,9 => CTR => B5: 4,7
* INC B5: 4,7 # B8: 5,9 => UNS
* DIS B5: 4,7 # B9: 5,9 => CTR => B9: 4,7
* PRF B5: 4,7 + B9: 4,7 # C5: 5,9 => SOL
* STA B5: 4,7 + B9: 4,7 + C5: 5,9
* CNT   4 HDP CHAINS /   4 HYP OPENED