Analysis of xx-top500-185-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...62..3..71...............9...4..5.2...1..........8.....7..1.235.8.............. initial

Autosolve

position: 5..624731.7158392..231795.891.34.25.2.591...373425681984.7351.23528.1...1.74.2385 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* PRF # H8: 4,6 => SOL
* PRF # H5: 6,7 => SOL
* DIS # H5: 4 => CTR => H5: 6,7
* PRF # I8: 6,7 => SOL
* DIS # I8: 4 => CTR => I8: 6,7
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* PRF # H8: 4,6 => SOL
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  18 HDP CHAINS /  20 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 # I8: 4,6 => CTR => I8: 7
* PRF I8: 7 => SOL
* STA I8: 7
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

...62..3..71...............9...4..5.2...1..........8.....7..1.235.8.............. initial
5..624731.7158392..231795.891.34.25.2.591...373425681984.7351.23528.1...1.74.2385 autosolve
589624731671583924423179568918347256265918473734256819846735192352891647197462385 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (18)
B1: 8,9
C1: 8,9
A2: 4,6
A3: 4,6
I2: 4,6
H3: 4,6
C4: 6,8
B5: 6,8
F4: 7,8
F5: 7,8
I4: 6,7
G5: 4,6
C7: 6,9
B9: 6,9
E8: 6,9
E9: 6,9
H7: 6,9
G8: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,A3: 4.. / A2 = 4  =>  0 pairs (X) / A3 = 4  =>  0 pairs (_)
I2,H3: 4.. / I2 = 4  =>  0 pairs (*) / H3 = 4  =>  0 pairs (X)
G5,H5: 4.. / G5 = 4  =>  0 pairs (*) / H5 = 4  =>  0 pairs (X)
A2,I2: 4.. / A2 = 4  =>  0 pairs (X) / I2 = 4  =>  0 pairs (_)
A3,H3: 4.. / A3 = 4  =>  0 pairs (*) / H3 = 4  =>  0 pairs (X)
G5,G8: 4.. / G5 = 4  =>  0 pairs (*) / G8 = 4  =>  0 pairs (X)
I2,I8: 4.. / I2 = 4  =>  0 pairs (*) / I8 = 4  =>  0 pairs (X)
A2,A3: 6.. / A2 = 6  =>  0 pairs (*) / A3 = 6  =>  0 pairs (X)
I2,H3: 6.. / I2 = 6  =>  0 pairs (X) / H3 = 6  =>  0 pairs (_)
C4,B5: 6.. / C4 = 6  =>  0 pairs (X) / B5 = 6  =>  0 pairs (_)
C7,B9: 6.. / C7 = 6  =>  0 pairs (*) / B9 = 6  =>  0 pairs (X)
E8,E9: 6.. / E8 = 6  =>  0 pairs (X) / E9 = 6  =>  0 pairs (_)
A2,I2: 6.. / A2 = 6  =>  0 pairs (*) / I2 = 6  =>  0 pairs (X)
A3,H3: 6.. / A3 = 6  =>  0 pairs (X) / H3 = 6  =>  0 pairs (_)
C4,I4: 6.. / C4 = 6  =>  0 pairs (X) / I4 = 6  =>  0 pairs (_)
C7,H7: 6.. / C7 = 6  =>  0 pairs (*) / H7 = 6  =>  0 pairs (X)
B9,E9: 6.. / B9 = 6  =>  0 pairs (X) / E9 = 6  =>  0 pairs (_)
B5,B9: 6.. / B5 = 6  =>  0 pairs (*) / B9 = 6  =>  0 pairs (X)
C4,C7: 6.. / C4 = 6  =>  0 pairs (X) / C7 = 6  =>  0 pairs (_)
G5,G8: 6.. / G5 = 6  =>  0 pairs (X) / G8 = 6  =>  0 pairs (_)
F4,F5: 7.. / F4 = 7  =>  0 pairs (*) / F5 = 7  =>  0 pairs (X)
I4,H5: 7.. / I4 = 7  =>  0 pairs (X) / H5 = 7  =>  0 pairs (_)
H8,I8: 7.. / H8 = 7  =>  0 pairs (X) / I8 = 7  =>  0 pairs (_)
F4,I4: 7.. / F4 = 7  =>  0 pairs (*) / I4 = 7  =>  0 pairs (X)
F5,H5: 7.. / F5 = 7  =>  0 pairs (X) / H5 = 7  =>  0 pairs (_)
H5,H8: 7.. / H5 = 7  =>  0 pairs (*) / H8 = 7  =>  0 pairs (X)
I4,I8: 7.. / I4 = 7  =>  0 pairs (X) / I8 = 7  =>  0 pairs (_)
B1,C1: 8.. / B1 = 8  =>  0 pairs (*) / C1 = 8  =>  0 pairs (X)
C4,B5: 8.. / C4 = 8  =>  0 pairs (*) / B5 = 8  =>  0 pairs (X)
F4,F5: 8.. / F4 = 8  =>  0 pairs (X) / F5 = 8  =>  0 pairs (_)
C4,F4: 8.. / C4 = 8  =>  0 pairs (*) / F4 = 8  =>  0 pairs (X)
B5,F5: 8.. / B5 = 8  =>  0 pairs (X) / F5 = 8  =>  0 pairs (_)
B1,B5: 8.. / B1 = 8  =>  0 pairs (*) / B5 = 8  =>  0 pairs (X)
C1,C4: 8.. / C1 = 8  =>  0 pairs (X) / C4 = 8  =>  0 pairs (_)
B1,C1: 9.. / B1 = 9  =>  0 pairs (X) / C1 = 9  =>  0 pairs (_)
C7,B9: 9.. / C7 = 9  =>  0 pairs (X) / B9 = 9  =>  0 pairs (_)
E8,E9: 9.. / E8 = 9  =>  0 pairs (*) / E9 = 9  =>  0 pairs (X)
H7,H8: 9.. / H7 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
C7,H7: 9.. / C7 = 9  =>  0 pairs (X) / H7 = 9  =>  0 pairs (_)
E8,H8: 9.. / E8 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
B9,E9: 9.. / B9 = 9  =>  0 pairs (*) / E9 = 9  =>  0 pairs (X)
B1,B9: 9.. / B1 = 9  =>  0 pairs (X) / B9 = 9  =>  0 pairs (_)
C1,C7: 9.. / C1 = 9  =>  0 pairs (*) / C7 = 9  =>  0 pairs (X)
* DURATION: 0:01:17.650648  START: 09:00:40.609714  END: 09:01:58.260362 2017-05-04
* CP COUNT: (43)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,B1,B5,B9,C1,C4,C7,E8,E9,F4,F5,G5,G8,H3,H7,I2,I4)
* 5..624731.7158392..231795.891.34.25.2.591...373425681984.7351.23528.1...1.74.2385
* PAIR I2: 4,6 COL I
I8: 4,6,7                                # reduction candidate for 4,6
I8: 4,6 => CTR
* 5..624731.7158392..231795.8916348257285917..37342568198497351.23528.1.7.1.74.2385
I8: 7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* PAIR H3: 4,6 COL H
H5: 4,6,7                                # reduction candidate for 4,6
H5: 4,6 => CTR
* 5..624731.7158392..231795.8916348257285917..37342568198497351.23528.1.7.1.74.2385
H5: 7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
H8: 4,6,7,9                              # reduction candidate for 4,6
H8: 4,6 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
H8: 7,9                                  # 19 pairs
* PAIR I4: 6,7 BLK 6
H5: 6,7,4                                # reduction candidate for 6,7
H5: 6,7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
H5: 4 => CTR
* 5..624731.7158392..231795.891.34.2572.591764373425681984.7351.23528.1476167492385
* PAIR I4: 6,7 COL I
I8: 6,7,4                                # reduction candidate for 6,7
I8: 6,7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
I8: 4 => CTR
* 5..62473147158392662317954891634825728591746373425681984.7351.23528.1.741.74.2385
* PAIR G5: 4,6 BLK 6
H5: 4,6,7                                # reduction candidate for 4,6
H5: 4,6 => CTR
* 5..624731.7158392..231795.8916348257285917..37342568198497351.23528.1.7.1.74.2385
H5: 7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* PAIR E8: 6,9 ROW 8
H8: 6,9,4,7                              # reduction candidate for 6,9
H8: 6,9 => CTR
* 5..624731.7158392442317956891.34725626591847373425681984.7351.23528.1..71.74.2385
H8: 4,7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* PAIR H7: 6,9 BLK 9
H8: 6,9,4,7                              # reduction candidate for 6,9
H8: 6,9 => CTR
* 5..624731.7158392442317956891.34725626591847373425681984.7351.23528.1..71.74.2385
H8: 4,7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* PAIR G8: 4,6 BLK 9
H8: 4,6,7,9                              # reduction candidate for 4,6
H8: 4,6 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
H8: 7,9                                  # 19 pairs
I8: 4,6,7                                # reduction candidate for 4,6
I8: 4,6 => CTR
* 5..624731.7158392..231795.8916348257285917..37342568198497351.23528.1.7.1.74.2385
I8: 7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-185-base-pr-000.dot
* REASONING
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* PRF # H8: 4,6 => SOL
* PRF # H5: 6,7 => SOL
* DIS # H5: 4 => CTR => H5: 6,7
* PRF # I8: 6,7 => SOL
* DIS # I8: 4 => CTR => I8: 6,7
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* PRF # H8: 4,6 => SOL
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  18 HDP CHAINS /  20 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,B1,B5,B9,C1,C4,C7,E8,E9,F4,F5,G5,G8,H3,H7,I2,I4)
* 5..624731.7158392..231795.891.34.25.2.591...373425681984.7351.23528.1...1.74.2385
* PAIR I2: 4,6 COL I
I8: 4,6,7                                # reduction candidate for 4,6
I8: 4,6 => CTR
* 5..624731.7158392..231795.8916348257285917..37342568198497351.23528.1.7.1.74.2385
I8: 7 => SOLVED
* 589624731671583924423179568918347256265918473734256819846735192352891647197462385
* DURATION: 0:00:03.176299  START: 09:02:24.152564  END: 09:02:27.328863 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-185-base-pr-001.dot
* REASONING
* DIS # I8: 4,6 => CTR => I8: 7
* PRF I8: 7 => SOL
* STA I8: 7
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 185

solution: 589624731671583924423179568918347256265918473734256819846735192352891647197462385
info: 1830     FNBTWY   S8.f     42754

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

Solution

position: 589624731671583924423179568918347256265918473734256819846735192352891647197462385 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 # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* PRF # H8: 4,6 => SOL
* INC # H8: 7,9 => UNS
* PRF # H5: 6,7 => SOL
* DIS # H5: 4 => CTR => H5: 6,7
* PRF # I8: 6,7 => SOL
* DIS # I8: 4 => CTR => I8: 6,7
* DIS # H5: 4,6 => CTR => H5: 7
* PRF # H5: 7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* DIS # H8: 6,9 => CTR => H8: 4,7
* PRF # H8: 4,7 => SOL
* PRF # H8: 4,6 => SOL
* INC # H8: 7,9 => UNS
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  20 HDP CHAINS /  20 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # I8: 4,6 => CTR => I8: 7
* PRF I8: 7 => SOL
* STA I8: 7
* CNT   2 HDP CHAINS /   1 HYP OPENED