Analysis of xx-top500-039-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6....27....8.5.....4.......7.....2.....48.......3.....2....3..........491......3. initial

Autosolve

position: 6..94278332875.49.947.38.2.783.192.459248.3..4..32.9.82.4.93...83.27..49179.64.32 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I3: 1,6 => CTR => I3: 5
* DIS # I3: 1,6 => CTR => I3: 5
* DIS # I7: 1,6 => CTR => I7: 5,7
* DIS # H5: 6,7 => CTR => H5: 1
* DIS # G7: 5,6 => CTR => G7: 1,8
* DIS # I7: 5,6 => CTR => I7: 1,7
* PRF # G8: 5,6 => SOL
* DIS # G8: 1 => CTR => G8: 5,6
* PRF # D7: 8 => SOL
* DIS # G8: 6 => CTR => G8: 1,5
* PRF # D7: 5,8 => SOL
* DIS # D7: 1 => CTR => D7: 5,8
* PRF # G7: 1,6 => SOL
* CNT  13 HDP CHAINS /  26 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 # I3: 1,6 => CTR => I3: 5
* DIS I3: 5 # I7: 1,6 => CTR => I7: 7
* DIS I3: 5 + I7: 7 # H5: 6,7 => CTR => H5: 1
* PRF I3: 5 + I7: 7 + H5: 1 => SOL
* STA I3: 5 + I7: 7 + H5: 1
* CNT   4 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

6....27....8.5.....4.......7.....2.....48.......3.....2....3..........491......3. initial
6..94278332875.49.947.38.2.783.192.459248.3..4..32.9.82.4.93...83.27..49179.64.32 autosolve
615942783328756491947138625783619254592487316461325978254893167836271549179564832 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
B1: 1,5
C1: 1,5
F2: 1,6
D3: 1,6
I2: 1,6
B6: 1,6
C6: 1,6
D4: 5,6
F5: 6,7
F6: 5,7
H4: 5,6
H6: 5,7
B7: 5,6
C8: 5,6
F8: 1,5
D9: 5,8
G9: 5,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B1,C1: 1.. / B1 = 1  => 14 pairs (_) / C1 = 1  =>  0 pairs (X)
F2,D3: 1.. / F2 = 1  =>  0 pairs (X) / D3 = 1  =>  0 pairs (_)
B6,C6: 1.. / B6 = 1  =>  0 pairs (X) / C6 = 1  => 14 pairs (_)
H5,I5: 1.. / H5 = 1  => 19 pairs (_) / I5 = 1  =>  0 pairs (X)
D7,F8: 1.. / D7 = 1  =>  0 pairs (X) / F8 = 1  =>  0 pairs (_)
F2,I2: 1.. / F2 = 1  =>  0 pairs (X) / I2 = 1  =>  0 pairs (_)
F8,G8: 1.. / F8 = 1  =>  0 pairs (*) / G8 = 1  =>  0 pairs (X)
B1,B6: 1.. / B1 = 1  => 14 pairs (_) / B6 = 1  =>  0 pairs (X)
C1,C6: 1.. / C1 = 1  =>  0 pairs (X) / C6 = 1  => 14 pairs (_)
D3,D7: 1.. / D3 = 1  =>  0 pairs (*) / D7 = 1  =>  0 pairs (X)
F2,F8: 1.. / F2 = 1  =>  0 pairs (X) / F8 = 1  =>  0 pairs (_)
H5,H7: 1.. / H5 = 1  => 19 pairs (_) / H7 = 1  =>  0 pairs (X)
B1,C1: 5.. / B1 = 5  =>  0 pairs (X) / C1 = 5  => 14 pairs (_)
G3,I3: 5.. / G3 = 5  =>  0 pairs (X) / I3 = 5  => 18 pairs (_)
D4,F6: 5.. / D4 = 5  =>  0 pairs (X) / F6 = 5  =>  0 pairs (_)
H4,H6: 5.. / H4 = 5  =>  0 pairs (*) / H6 = 5  =>  0 pairs (X)
B7,C8: 5.. / B7 = 5  => 14 pairs (_) / C8 = 5  =>  0 pairs (X)
D4,H4: 5.. / D4 = 5  =>  0 pairs (X) / H4 = 5  =>  0 pairs (_)
F6,H6: 5.. / F6 = 5  =>  0 pairs (*) / H6 = 5  =>  0 pairs (X)
D9,G9: 5.. / D9 = 5  =>  0 pairs (*) / G9 = 5  =>  0 pairs (X)
B1,B7: 5.. / B1 = 5  =>  0 pairs (X) / B7 = 5  => 14 pairs (_)
C1,C8: 5.. / C1 = 5  => 14 pairs (_) / C8 = 5  =>  0 pairs (X)
F6,F8: 5.. / F6 = 5  =>  0 pairs (*) / F8 = 5  =>  0 pairs (X)
I3,I7: 5.. / I3 = 5  => 18 pairs (_) / I7 = 5  =>  0 pairs (X)
F2,D3: 6.. / F2 = 6  =>  0 pairs (*) / D3 = 6  =>  0 pairs (X)
B6,C6: 6.. / B6 = 6  => 14 pairs (_) / C6 = 6  =>  0 pairs (X)
D4,F5: 6.. / D4 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
B7,C8: 6.. / B7 = 6  =>  0 pairs (X) / C8 = 6  => 14 pairs (_)
F2,I2: 6.. / F2 = 6  =>  0 pairs (*) / I2 = 6  =>  0 pairs (X)
D4,H4: 6.. / D4 = 6  =>  0 pairs (*) / H4 = 6  =>  0 pairs (X)
C8,G8: 6.. / C8 = 6  => 14 pairs (_) / G8 = 6  =>  0 pairs (X)
B6,B7: 6.. / B6 = 6  => 14 pairs (_) / B7 = 6  =>  0 pairs (X)
C6,C8: 6.. / C6 = 6  =>  0 pairs (X) / C8 = 6  => 14 pairs (_)
D3,D4: 6.. / D3 = 6  =>  0 pairs (X) / D4 = 6  =>  0 pairs (_)
F2,F5: 6.. / F2 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
F5,F6: 7.. / F5 = 7  =>  0 pairs (*) / F6 = 7  =>  0 pairs (X)
H7,I7: 7.. / H7 = 7  =>  0 pairs (X) / I7 = 7  => 20 pairs (_)
F6,H6: 7.. / F6 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
I5,I7: 7.. / I5 = 7  =>  0 pairs (X) / I7 = 7  => 20 pairs (_)
D7,D9: 8.. / D7 = 8  =>  0 pairs (*) / D9 = 8  =>  0 pairs (X)
G7,G9: 8.. / G7 = 8  => 18 pairs (_) / G9 = 8  =>  0 pairs (*)
D7,G7: 8.. / D7 = 8  =>  0 pairs (*) / G7 = 8  =>  0 pairs (X)
D9,G9: 8.. / D9 = 8  => 18 pairs (_) / G9 = 8  =>  0 pairs (*)
* DURATION: 0:01:22.926905  START: 03:59:49.164087  END: 04:01:12.090992 2017-05-04
* CP COUNT: (43)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B6,B7,C1,C6,C8,D3,D4,D9,F2,F5,F6,F8,G9,H4,H6,I2)
* 6..94278332875.49.947.38.2.783.192.459248.3..4..32.9.82.4.93...83.27..49179.64.32
* PAIR D3: 1,6 ROW 3
G3: 1,6,5                                # reduction candidate for 1,6
G3: 1,6                                  # 18 pairs
I3: 1,6,5                                # reduction candidate for 1,6
I3: 1,6 => CTR
* 65194278332875649194713852678361925459248.3..4..32.9.82.4.93..5835271649179564832
I3: 5                                    # 18 pairs
* PAIR I2: 1,6 BLK 3
G3: 1,6,5                                # reduction candidate for 1,6
G3: 1,6                                  # 18 pairs
I3: 1,6,5                                # reduction candidate for 1,6
I3: 1,6 => CTR
* 65194278332875649194713852678361925459248.3..4..32.9.82.4.93..5835271649179564832
I3: 5                                    # 18 pairs
* PAIR I2: 1,6 COL I
I5: 1,6,7                                # reduction candidate for 1,6
I5: 1,6                                  # 20 pairs
I7: 1,6,5,7                              # reduction candidate for 1,6
I7: 1,6 => CTR
* 6.5942783328751496947.38.25783.192.459248.3.74..3279582.4.93.7.83.275149179864532
I7: 5,7                                  # 18 pairs
* PAIR F5: 6,7 ROW 5
H5: 6,7,1                                # reduction candidate for 6,7
H5: 6,7 => CTR
* 6..94278332875.49.947.38.2.783.192.459248.3.14..32.9.82.4.93.1783.271.49179.64.32
H5: 1                                    # 19 pairs
I5: 6,7,1                                # reduction candidate for 6,7
I5: 6,7                                  # 19 pairs
* PAIR B7: 5,6 ROW 7
G7: 5,6,1,8                              # reduction candidate for 5,6
G7: 5,6 => CTR
* 6..942783328756491947138.2.7836192545924873164..3259782.4893.67836271549179564832
G7: 1,8                                  # 18 pairs
I7: 5,6,1,7                              # reduction candidate for 5,6
I7: 5,6 => CTR
* 6.5942783328751496947.38.2.783.192.459248.3.74..3279582.4.93.7.83.275149179864532
I7: 1,7                                  # 19 pairs
* PAIR C8: 5,6 ROW 8
G8: 5,6,1                                # reduction candidate for 5,6
G8: 5,6 => SOLVED
* 615942783328756491947138625783619254592487316461325978254893167836271549179564832
G8: 1 => CTR
* 6.5942783328751496947.38.2.783.192.459248.3..4..32.9.82.4.93...836275149179864532
* PAIR F8: 1,5 BLK 8
D7: 1,5,8                                # reduction candidate for 1,5
D7: 8 => SOLVED
* 615942783328756491947138625783619254592487316461325978254893167836271549179564832
D7: 1,5                                  # 18 pairs
* PAIR F8: 1,5 ROW 8
G8: 1,5,6                                # reduction candidate for 1,5
G8: 6 => CTR
* 6..94278332875649194713852678361925459248.3..4..32.9.82.4.93...83.271649179.64.32
G8: 1,5                                  # 14 pairs
* PAIR D9: 5,8 BLK 8
D7: 5,8,1                                # reduction candidate for 5,8
D7: 5,8 => SOLVED
* 615942783328756491947138625783619254592487316461325978254893167836271549179564832
D7: 1 => CTR
* 6..94278332875.49.947.38.2.783.192.459248.3..4..32.9.82.41938..83.275149179864532
* PAIR G9: 5,8 BLK 9
G7: 5,8,1,6                              # reduction candidate for 5,8
G7: 1,6 => SOLVED
* 615942783328756491947138625783619254592487316461325978254893167836271549179564832
G7: 5,8                                  # 20 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-039-base-pr-000.dot
* REASONING
* DIS # I3: 1,6 => CTR => I3: 5
* DIS # I3: 1,6 => CTR => I3: 5
* DIS # I7: 1,6 => CTR => I7: 5,7
* DIS # H5: 6,7 => CTR => H5: 1
* DIS # G7: 5,6 => CTR => G7: 1,8
* DIS # I7: 5,6 => CTR => I7: 1,7
* PRF # G8: 5,6 => SOL
* DIS # G8: 1 => CTR => G8: 5,6
* PRF # D7: 8 => SOL
* DIS # G8: 6 => CTR => G8: 1,5
* PRF # D7: 5,8 => SOL
* DIS # D7: 1 => CTR => D7: 5,8
* PRF # G7: 1,6 => SOL
* CNT  13 HDP CHAINS /  26 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B1,B6,B7,C1,C6,C8,D3,D4,D9,F2,F5,F6,F8,G9,H4,H6,I2)
* 6..94278332875.49.947.38.2.783.192.459248.3..4..32.9.82.4.93...83.27..49179.64.32
* PAIR D3: 1,6 ROW 3
G3: 1,6,5                                # reduction candidate for 1,6
G3: 1,6                                  # 18 pairs
I3: 1,6,5                                # reduction candidate for 1,6
I3: 1,6 => CTR
* 65194278332875649194713852678361925459248.3..4..32.9.82.4.93..5835271649179564832
* RESTART
* PAIR RESTART
* PAIR I2: 1,6 COL I
I5: 1,6,7                                # reduction candidate for 1,6
I5: 1,6                                  # 20 pairs
I7: 1,6,7                                # reduction candidate for 1,6
I7: 1,6 => CTR
* 6.5942783328751496947.38.25783.192.459248.3.74..3279582.4.93.7.83.275149179864532
* RESTART
* PAIR RESTART
* PAIR F5: 6,7 ROW 5
H5: 6,7,1                                # reduction candidate for 6,7
H5: 6,7 => CTR
* 6..94278332875.49.947.38.25783.192.459248.3.14..32.9.82.4.93.1783.271.49179.64.32
H5: 1 => SOLVED
* 615942783328756491947138625783619254592487316461325978254893167836271549179564832
* DURATION: 0:00:08.029012  START: 04:01:42.061779  END: 04:01:50.090791 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-039-base-pr-001.dot
* REASONING
* DIS # I3: 1,6 => CTR => I3: 5
* DIS I3: 5 # I7: 1,6 => CTR => I7: 7
* DIS I3: 5 + I7: 7 # H5: 6,7 => CTR => H5: 1
* PRF I3: 5 + I7: 7 + H5: 1 => SOL
* STA I3: 5 + I7: 7 + H5: 1
* CNT   4 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 039

solution: 615942783328756491947138625783619254592487316461325978254893167836271549179564832
info: 1370     FNBHWXY  S8.f     34423

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

Solution

position: 615942783328756491947138625783619254592487316461325978254893167836271549179564832 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 # G3: 1,6 => UNS
* DIS # I3: 1,6 => CTR => I3: 5
* INC # I3: 5 => UNS
* INC # G3: 1,6 => UNS
* DIS # I3: 1,6 => CTR => I3: 5
* INC # I3: 5 => UNS
* INC # I5: 1,6 => UNS
* DIS # I7: 1,6 => CTR => I7: 5,7
* INC # I7: 5,7 => UNS
* DIS # H5: 6,7 => CTR => H5: 1
* INC # H5: 1 => UNS
* INC # I5: 6,7 => UNS
* DIS # G7: 5,6 => CTR => G7: 1,8
* INC # G7: 1,8 => UNS
* DIS # I7: 5,6 => CTR => I7: 1,7
* INC # I7: 1,7 => UNS
* PRF # G8: 5,6 => SOL
* DIS # G8: 1 => CTR => G8: 5,6
* INC # D7: 1,5 => UNS
* PRF # D7: 8 => SOL
* INC # G8: 1,5 => UNS
* DIS # G8: 6 => CTR => G8: 1,5
* PRF # D7: 5,8 => SOL
* DIS # D7: 1 => CTR => D7: 5,8
* INC # G7: 5,8 => UNS
* PRF # G7: 1,6 => SOL
* CNT  26 HDP CHAINS /  26 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # G3: 1,6 => UNS
* DIS # I3: 1,6 => CTR => I3: 5
* INC I3: 5 # I5: 1,6 => UNS
* DIS I3: 5 # I7: 1,6 => CTR => I7: 7
* DIS I3: 5 + I7: 7 # H5: 6,7 => CTR => H5: 1
* PRF I3: 5 + I7: 7 + H5: 1 => SOL
* STA I3: 5 + I7: 7 + H5: 1
* CNT   6 HDP CHAINS /   5 HYP OPENED