Analysis of xx-top500-353-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2....7.54..3........6.....5.....1..6.3.........8......8..7...........46....5..3. initial

Autosolve

position: 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735.8..46....56837 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # A9: 1,2 => SOL
* DIS # A9: 9 => CTR => A9: 1,2
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* DIS # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* CNT  14 HDP CHAINS /  14 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 # D8: 1,9 => CTR => D8: 2
* PRF D8: 2 => SOL
* STA D8: 2
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.2....7.54..3........6.....5.....1..6.3.........8......8..7...........46....5..3. initial
32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735.8..46....56837 autosolve
329148765467395281851627394548769123693512478172834659986473512735281946214956837 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (22)
C1: 1,9
C3: 1,9
D1: 1,9
E2: 1,9
G2: 2,9
I2: 1,2
H3: 1,9
B4: 4,9
B5: 1,9
A6: 1,2
C6: 2,4
F4: 4,9
E5: 1,9
F6: 1,4
A7: 2,9
B9: 1,4
C9: 2,4
F8: 1,9
D9: 2,9
H7: 1,9
I7: 1,2
G8: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C1,C3: 1.. / C1 = 1  =>  0 pairs (X) / C3 = 1  =>  0 pairs (_)
D1,E2: 1.. / D1 = 1  =>  0 pairs (*) / E2 = 1  =>  0 pairs (X)
I2,H3: 1.. / I2 = 1  =>  0 pairs (*) / H3 = 1  =>  0 pairs (X)
B5,A6: 1.. / B5 = 1  =>  0 pairs (X) / A6 = 1  =>  0 pairs (_)
E5,F6: 1.. / E5 = 1  =>  0 pairs (*) / F6 = 1  =>  0 pairs (X)
A9,B9: 1.. / A9 = 1  =>  0 pairs (X) / B9 = 1  =>  0 pairs (_)
D8,F8: 1.. / D8 = 1  =>  0 pairs (X) / F8 = 1  =>  0 pairs (_)
H7,I7: 1.. / H7 = 1  =>  0 pairs (*) / I7 = 1  =>  0 pairs (X)
C1,D1: 1.. / C1 = 1  =>  0 pairs (X) / D1 = 1  =>  0 pairs (_)
E2,I2: 1.. / E2 = 1  =>  0 pairs (X) / I2 = 1  =>  0 pairs (_)
C3,H3: 1.. / C3 = 1  =>  0 pairs (*) / H3 = 1  =>  0 pairs (X)
B5,E5: 1.. / B5 = 1  =>  0 pairs (X) / E5 = 1  =>  0 pairs (_)
A6,F6: 1.. / A6 = 1  =>  0 pairs (*) / F6 = 1  =>  0 pairs (X)
A6,A9: 1.. / A6 = 1  =>  0 pairs (*) / A9 = 1  =>  0 pairs (X)
B5,B9: 1.. / B5 = 1  =>  0 pairs (X) / B9 = 1  =>  0 pairs (_)
D1,D8: 1.. / D1 = 1  =>  0 pairs (*) / D8 = 1  =>  0 pairs (X)
E2,E5: 1.. / E2 = 1  =>  0 pairs (X) / E5 = 1  =>  0 pairs (_)
F6,F8: 1.. / F6 = 1  =>  0 pairs (X) / F8 = 1  =>  0 pairs (_)
H3,H7: 1.. / H3 = 1  =>  0 pairs (X) / H7 = 1  =>  0 pairs (_)
I2,I7: 1.. / I2 = 1  =>  0 pairs (*) / I7 = 1  =>  0 pairs (X)
G2,I2: 2.. / G2 = 2  =>  0 pairs (*) / I2 = 2  =>  0 pairs (X)
A6,C6: 2.. / A6 = 2  =>  0 pairs (X) / C6 = 2  =>  0 pairs (_)
D8,D9: 2.. / D8 = 2  =>  0 pairs (*) / D9 = 2  =>  0 pairs (X)
I7,G8: 2.. / I7 = 2  =>  0 pairs (*) / G8 = 2  =>  0 pairs (X)
A7,I7: 2.. / A7 = 2  =>  0 pairs (X) / I7 = 2  =>  0 pairs (_)
D8,G8: 2.. / D8 = 2  =>  0 pairs (*) / G8 = 2  =>  0 pairs (X)
C6,C9: 2.. / C6 = 2  =>  0 pairs (*) / C9 = 2  =>  0 pairs (X)
G2,G8: 2.. / G2 = 2  =>  0 pairs (*) / G8 = 2  =>  0 pairs (X)
I2,I7: 2.. / I2 = 2  =>  0 pairs (X) / I7 = 2  =>  0 pairs (_)
B4,C6: 4.. / B4 = 4  =>  0 pairs (*) / C6 = 4  =>  0 pairs (X)
F4,F6: 4.. / F4 = 4  =>  0 pairs (X) / F6 = 4  =>  0 pairs (_)
B9,C9: 4.. / B9 = 4  =>  0 pairs (X) / C9 = 4  =>  0 pairs (_)
B4,F4: 4.. / B4 = 4  =>  0 pairs (*) / F4 = 4  =>  0 pairs (X)
C6,F6: 4.. / C6 = 4  =>  0 pairs (X) / F6 = 4  =>  0 pairs (_)
B4,B9: 4.. / B4 = 4  =>  0 pairs (*) / B9 = 4  =>  0 pairs (X)
C6,C9: 4.. / C6 = 4  =>  0 pairs (X) / C9 = 4  =>  0 pairs (_)
C1,C3: 9.. / C1 = 9  =>  0 pairs (*) / C3 = 9  =>  0 pairs (X)
D1,E2: 9.. / D1 = 9  =>  0 pairs (X) / E2 = 9  =>  0 pairs (_)
G2,H3: 9.. / G2 = 9  =>  0 pairs (X) / H3 = 9  =>  0 pairs (_)
B4,B5: 9.. / B4 = 9  =>  0 pairs (X) / B5 = 9  =>  0 pairs (_)
F4,E5: 9.. / F4 = 9  =>  0 pairs (*) / E5 = 9  =>  0 pairs (X)
A7,A9: 9.. / A7 = 9  =>  0 pairs (*) / A9 = 9  =>  0 pairs (X)
H7,G8: 9.. / H7 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
C1,D1: 9.. / C1 = 9  =>  0 pairs (*) / D1 = 9  =>  0 pairs (X)
E2,G2: 9.. / E2 = 9  =>  0 pairs (*) / G2 = 9  =>  0 pairs (X)
C3,H3: 9.. / C3 = 9  =>  0 pairs (X) / H3 = 9  =>  0 pairs (_)
B4,F4: 9.. / B4 = 9  =>  0 pairs (X) / F4 = 9  =>  0 pairs (_)
B5,E5: 9.. / B5 = 9  =>  0 pairs (*) / E5 = 9  =>  0 pairs (X)
A7,H7: 9.. / A7 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
A9,D9: 9.. / A9 = 9  =>  0 pairs (X) / D9 = 9  =>  0 pairs (_)
E2,E5: 9.. / E2 = 9  =>  0 pairs (*) / E5 = 9  =>  0 pairs (X)
F4,F8: 9.. / F4 = 9  =>  0 pairs (*) / F8 = 9  =>  0 pairs (X)
G2,G8: 9.. / G2 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
H3,H7: 9.. / H3 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
* DURATION: 0:01:36.514254  START: 14:48:42.841288  END: 14:50:19.355542 2017-05-04
* CP COUNT: (54)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,A7,B4,B5,B9,C1,C3,C6,C9,D1,D9,E2,E5,F4,F6,F8,G2,G8,H3,H7,I2,I7)
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735.8..46....56837
* PAIR D1: 1,9 COL D
D8: 1,9,2                                # reduction candidate for 1,9
D8: 1,9 => CTR
* 32..487654673.59828596273145.876.1236.3592478.7283.659.864735..735.8.246...256837
D8: 2 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
* PAIR A6: 1,2 COL A
A9: 1,2,9                                # reduction candidate for 1,2
A9: 1,2 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
A9: 9 => CTR
* 32.148765467395.8.85.6273.45.876.1236.35.2478172834659286473591735.81246914256837
* PAIR A7: 2,9 BLK 7
A9: 2,9,1                                # reduction candidate for 2,9
A9: 2,9 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
A9: 1 => CTR
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.6599864735127352819461...56837
* PAIR F8: 1,9 BLK 8
D8: 1,9,2                                # reduction candidate for 1,9
D8: 1,9 => CTR
* 32..487654673.59828596273145.876.1236.3592478.7283.659.864735..735.8.246...256837
D8: 2 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
* PAIR D9: 2,9 BLK 8
D8: 2,9,1                                # reduction candidate for 2,9
D8: 2,9 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
D8: 1 => CTR
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735189246914256837
* PAIR D9: 2,9 ROW 9
A9: 2,9,1                                # reduction candidate for 2,9
A9: 2,9 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
A9: 1 => CTR
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.6599864735127352819461...56837
* PAIR G8: 2,9 ROW 8
D8: 2,9,1                                # reduction candidate for 2,9
D8: 2,9 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
D8: 1 => CTR
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735189246914256837
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-353-base-pr-000.dot
* REASONING
* DIS # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # A9: 1,2 => SOL
* DIS # A9: 9 => CTR => A9: 1,2
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* DIS # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* CNT  14 HDP CHAINS /  14 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,A7,B4,B5,B9,C1,C3,C6,C9,D1,D9,E2,E5,F4,F6,F8,G2,G8,H3,H7,I2,I7)
* 32..487654673.5.8.85.6273.45.876.1236.35.2478.7.83.659.864735..735.8..46....56837
* PAIR D1: 1,9 COL D
D8: 1,9,2                                # reduction candidate for 1,9
D8: 1,9 => CTR
* 32..487654673.59828596273145.876.1236.3592478.7283.659.864735..735.8.246...256837
D8: 2 => SOLVED
* 329148765467395281851627394548769123693512478172834659986473512735281946214956837
* DURATION: 0:00:03.136621  START: 14:50:37.492542  END: 14:50:40.629163 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-353-base-pr-001.dot
* REASONING
* DIS # D8: 1,9 => CTR => D8: 2
* PRF D8: 2 => SOL
* STA D8: 2
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 353

solution: 329148765467395281851627394548769123693512478172834659986473512735281946214956837
info: 4885     FNBWY    S8.f     16394

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

Solution

position: 329148765467395281851627394548769123693512478172834659986473512735281946214956837 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 # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # A9: 1,2 => SOL
* DIS # A9: 9 => CTR => A9: 1,2
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* DIS # D8: 1,9 => CTR => D8: 2
* PRF # D8: 2 => SOL
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* PRF # A9: 2,9 => SOL
* DIS # A9: 1 => CTR => A9: 2,9
* PRF # D8: 2,9 => SOL
* DIS # D8: 1 => CTR => D8: 2,9
* CNT  14 HDP CHAINS /  14 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D8: 1,9 => CTR => D8: 2
* PRF D8: 2 => SOL
* STA D8: 2
* CNT   2 HDP CHAINS /   1 HYP OPENED