Analysis of xx-top500-211-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 4...6...........51....2.......7..2........43..18.......7.1.8...3.....6.....5..... initial

Autosolve

position: 4...61..........511...25......7.921.7...1243.218.......7.1.8...3.12..6.....5.61.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I4: 5,6 => CTR => I4: 8
* PRF # I4: 8 => SOL
* DIS # A7: 9 => CTR => A7: 5,6
* PRF # I4: 5,8 => SOL
* DIS # I4: 6 => CTR => I4: 5,8
* PRF # I5: 6,8 => SOL
* DIS # I5: 5 => CTR => I5: 6,8
* DIS # D6: 3,4 => CTR => D6: 6
* PRF # D6: 6 => SOL
* DIS # F2: 3,4 => CTR => F2: 7
* PRF # B8: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 2,4
* DIS # A2: 6 => CTR => A2: 8,9
* DIS # H8: 4,7 => CTR => H8: 8,9
* DIS # I8: 4,7 => CTR => I8: 5,9
* DIS # F2: 3 => CTR => F2: 4,7
* CNT  16 HDP CHAINS /  30 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 # I4: 5,6 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

4...6...........51....2.......7..2........43..18.......7.1.8...3.....6.....5..... initial
4...61..........511...25......7.921.7...1243.218.......7.1.8...3.12..6.....5.61.. autosolve
485361729962487351137925864643759218759812436218643597576138942391274685824596173 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
H3: 4,6
I3: 4,6
A4: 5,6
B4: 3,4
C4: 3,4
E4: 5,8
D5: 6,8
E6: 4,5
F6: 3,4
A9: 8,9
F8: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,C2: 2.. / B2 = 2  =>  0 pairs (X) / C2 = 2  => 12 pairs (_)
H1,I1: 2.. / H1 = 2  => 12 pairs (_) / I1 = 2  => 13 pairs (_)
B2,B9: 2.. / B2 = 2  =>  0 pairs (X) / B9 = 2  => 12 pairs (_)
B4,C4: 3.. / B4 = 3  => 11 pairs (_) / C4 = 3  => 10 pairs (_)
D6,F6: 3.. / D6 = 3  =>  0 pairs (X) / F6 = 3  => 12 pairs (_)
E7,E9: 3.. / E7 = 3  => 12 pairs (_) / E9 = 3  => 12 pairs (_)
E9,I9: 3.. / E9 = 3  => 12 pairs (_) / I9 = 3  => 12 pairs (_)
F2,F6: 3.. / F2 = 3  =>  0 pairs (X) / F6 = 3  => 12 pairs (_)
H3,I3: 4.. / H3 = 4  =>  0 pairs (X) / I3 = 4  => 10 pairs (_)
B4,C4: 4.. / B4 = 4  => 10 pairs (_) / C4 = 4  => 11 pairs (_)
D2,D6: 4.. / D2 = 4  => 14 pairs (_) / D6 = 4  =>  0 pairs (X)
B1,C1: 5.. / B1 = 5  =>  0 pairs (X) / C1 = 5  => 12 pairs (_)
E4,E6: 5.. / E4 = 5  =>  0 pairs (*) / E6 = 5  =>  0 pairs (X)
B8,I8: 5.. / B8 = 5  =>  0 pairs (X) / I8 = 5  =>  0 pairs (_)
A4,A7: 5.. / A4 = 5  =>  0 pairs (X) / A7 = 5  =>  0 pairs (_)
G6,G7: 5.. / G6 = 5  =>  0 pairs (*) / G7 = 5  =>  0 pairs (X)
H3,I3: 6.. / H3 = 6  => 10 pairs (_) / I3 = 6  =>  0 pairs (X)
D5,D6: 6.. / D5 = 6  =>  0 pairs (X) / D6 = 6  =>  0 pairs (_)
A7,C7: 6.. / A7 = 6  =>  0 pairs (X) / C7 = 6  => 13 pairs (_)
A4,I4: 6.. / A4 = 6  =>  0 pairs (*) / I4 = 6  =>  0 pairs (X)
B2,B5: 6.. / B2 = 6  => 15 pairs (_) / B5 = 6  =>  0 pairs (X)
H3,H6: 6.. / H3 = 6  => 10 pairs (_) / H6 = 6  =>  0 pairs (X)
C1,C3: 7.. / C1 = 7  =>  0 pairs (X) / C3 = 7  => 11 pairs (_)
E2,F2: 7.. / E2 = 7  =>  0 pairs (X) / F2 = 7  => 13 pairs (_)
C3,G3: 7.. / C3 = 7  => 11 pairs (_) / G3 = 7  =>  0 pairs (X)
F2,F8: 7.. / F2 = 7  => 13 pairs (_) / F8 = 7  =>  0 pairs (X)
E4,D5: 8.. / E4 = 8  =>  0 pairs (X) / D5 = 8  =>  0 pairs (_)
I4,I5: 8.. / I4 = 8  =>  0 pairs (*) / I5 = 8  =>  0 pairs (X)
H8,H9: 8.. / H8 = 8  => 11 pairs (_) / H9 = 8  =>  0 pairs (X)
E4,I4: 8.. / E4 = 8  =>  0 pairs (X) / I4 = 8  =>  0 pairs (_)
D5,I5: 8.. / D5 = 8  =>  0 pairs (*) / I5 = 8  =>  0 pairs (X)
B8,H8: 8.. / B8 = 8  =>  0 pairs (X) / H8 = 8  => 11 pairs (_)
A2,A9: 8.. / A2 = 8  =>  0 pairs (X) / A9 = 8  => 11 pairs (_)
E2,E4: 8.. / E2 = 8  =>  0 pairs (*) / E4 = 8  =>  0 pairs (X)
B5,C5: 9.. / B5 = 9  => 16 pairs (_) / C5 = 9  => 14 pairs (_)
* DURATION: 0:00:59.370779  START: 10:02:35.944831  END: 10:03:35.315610 2017-05-04
* CP COUNT: (35)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B4,C4,D5,E4,E6,F6,F8,H3,I3)
* 4...61..........511...25......7.921.7...1243.218.......7.1.8...3.12..6.....5.61..
* PAIR A4: 5,6 BLK 4
B5: 5,6,9                                # reduction candidate for 5,6
B5: 5,6                                  # 14 pairs
C5: 5,6,9                                # reduction candidate for 5,6
C5: 5,6                                  # 16 pairs
* PAIR A4: 5,6 ROW 4
I4: 5,6,8                                # reduction candidate for 5,6
I4: 5,6 => CTR
* 4...61..........511...25......78921.7..612438218.5.....7.1.85..3512..68....5.61..
I4: 8 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
* PAIR A4: 5,6 COL A
A7: 5,6,9                                # reduction candidate for 5,6
A7: 9 => CTR
* 4...61..........511...25...5..7892167...1243.218.......7.1.8...3.12..6.....5.61..
A7: 5,6                                  # 15 pairs
* PAIR E4: 5,8 ROW 4
I4: 5,8,6                                # reduction candidate for 5,8
I4: 5,8 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
I4: 6 => CTR
* 4...61..........511...25......7892167..612438218.5.....7.1.85..3512..68....5.61..
* PAIR D5: 6,8 ROW 5
I5: 6,8,5                                # reduction candidate for 6,8
I5: 6,8 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
I5: 5 => CTR
* 4...61..........511...25......7.92187..81243521865.....7.1.8...3.12..6.....5.61..
* PAIR F6: 3,4 BLK 5
D6: 3,4,6                                # reduction candidate for 3,4
D6: 3,4 => CTR
* 4...61....62....511...25...6..7892157..612438218.5....5761.8...3.12..6...2.5.61..
D6: 6 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
* PAIR F6: 3,4 COL F
F2: 3,4,7                                # reduction candidate for 3,4
F2: 3,4 => CTR
* 4...61.......7..511...25......78921.7..612438218.5.....7.1.85..3512.768....5.61..
F2: 7                                    # 13 pairs
* PAIR A9: 8,9 BLK 7
B8: 8,9,4,5                              # reduction candidate for 8,9
B8: 8,9 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
B8: 4,5                                  # 12 pairs
B9: 8,9,2,4                              # reduction candidate for 8,9
B9: 8,9 => CTR
* 4...61....2.....511...25......7.921.769812435218.......7.1.8...3.12..6.....5.61..
B9: 2,4                                  # 12 pairs
* PAIR A9: 8,9 ROW 9
H9: 8,9,2,4,7                            # reduction candidate for 8,9
H9: 8,9                                  # 16 pairs
H9: 2,4,7                                # 11 pairs
* PAIR A9: 8,9 COL A
A2: 8,9,6                                # reduction candidate for 8,9
A2: 6 => CTR
* 4...61...6......511...25...5..7892167...1243.218.......7.1.8...3.12..6.....5.61..
A2: 8,9                                  # 15 pairs
* PAIR F8: 4,7 BLK 8
E8: 4,7,9                                # reduction candidate for 4,7
E8: 4,7                                  # 16 pairs
E9: 4,7,3,9                              # reduction candidate for 4,7
E9: 4,7                                  # 13 pairs
* PAIR F8: 4,7 ROW 8
H8: 4,7,8,9                              # reduction candidate for 4,7
H8: 4,7 => CTR
* 4...61...8......511...25......7892167..612438218.5....6751.8...38129.6.59..5.618.
H8: 8,9                                  # 12 pairs
I8: 4,7,5,9                              # reduction candidate for 4,7
I8: 4,7 => CTR
* 4.5.61..........511.7.25...5..7892167...1243.218.......7.1.8...3512..68....5.61..
I8: 5,9                                  # 12 pairs
* PAIR F8: 4,7 COL F
F2: 4,7,3                                # reduction candidate for 4,7
F2: 3 => CTR
* 4...61.......73.511...25......78921.7..612438218354....7.1.85..3512.768....5.61..
F2: 4,7                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-211-base-pr-000.dot
* REASONING
* DIS # I4: 5,6 => CTR => I4: 8
* PRF # I4: 8 => SOL
* DIS # A7: 9 => CTR => A7: 5,6
* PRF # I4: 5,8 => SOL
* DIS # I4: 6 => CTR => I4: 5,8
* PRF # I5: 6,8 => SOL
* DIS # I5: 5 => CTR => I5: 6,8
* DIS # D6: 3,4 => CTR => D6: 6
* PRF # D6: 6 => SOL
* DIS # F2: 3,4 => CTR => F2: 7
* PRF # B8: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 2,4
* DIS # A2: 6 => CTR => A2: 8,9
* DIS # H8: 4,7 => CTR => H8: 8,9
* DIS # I8: 4,7 => CTR => I8: 5,9
* DIS # F2: 3 => CTR => F2: 4,7
* CNT  16 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B4,C4,D5,E4,E6,F6,F8,H3,I3)
* 4...61..........511...25......7.921.7...1243.218.......7.1.8...3.12..6.....5.61..
* PAIR A4: 5,6 BLK 4
B5: 5,6,9                                # reduction candidate for 5,6
B5: 5,6                                  # 14 pairs
C5: 5,6,9                                # reduction candidate for 5,6
C5: 5,6                                  # 16 pairs
* PAIR A4: 5,6 ROW 4
I4: 5,6,8                                # reduction candidate for 5,6
I4: 5,6 => CTR
* 4...61..........511...25......78921.7..612438218.5.....7.1.85..3512..68....5.61..
I4: 8 => SOLVED
* 485361729962487351137925864643759218759812436218643597576138942391274685824596173
* DURATION: 0:00:05.221856  START: 10:04:05.172435  END: 10:04:10.394291 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-211-base-pr-001.dot
* REASONING
* DIS # I4: 5,6 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 211

solution: 485361729962487351137925864643759218759812436218643597576138942391274685824596173
info: 1943     FNBHWY   S8.f     30747

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

Solution

position: 485361729962487351137925864643759218759812436218643597576138942391274685824596173 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 # B5: 5,6 => UNS
* INC # C5: 5,6 => UNS
* DIS # I4: 5,6 => CTR => I4: 8
* PRF # I4: 8 => SOL
* INC # A7: 5,6 => UNS
* DIS # A7: 9 => CTR => A7: 5,6
* PRF # I4: 5,8 => SOL
* DIS # I4: 6 => CTR => I4: 5,8
* PRF # I5: 6,8 => SOL
* DIS # I5: 5 => CTR => I5: 6,8
* DIS # D6: 3,4 => CTR => D6: 6
* PRF # D6: 6 => SOL
* DIS # F2: 3,4 => CTR => F2: 7
* INC # F2: 7 => UNS
* PRF # B8: 8,9 => SOL
* INC # B8: 4,5 => UNS
* DIS # B9: 8,9 => CTR => B9: 2,4
* INC # B9: 2,4 => UNS
* INC # H9: 8,9 => UNS
* INC # H9: 2,4,7 => UNS
* INC # A2: 8,9 => UNS
* DIS # A2: 6 => CTR => A2: 8,9
* INC # E8: 4,7 => UNS
* INC # E9: 4,7 => UNS
* DIS # H8: 4,7 => CTR => H8: 8,9
* INC # H8: 8,9 => UNS
* DIS # I8: 4,7 => CTR => I8: 5,9
* INC # I8: 5,9 => UNS
* INC # F2: 4,7 => UNS
* DIS # F2: 3 => CTR => F2: 4,7
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B5: 5,6 => UNS
* INC # C5: 5,6 => UNS
* DIS # I4: 5,6 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   4 HDP CHAINS /   3 HYP OPENED