Analysis of xx-top500-017-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .1..4.67.3..8...........5......71...9......3...........4....2.....9....8..73..... initial

Autosolve

position: .18.4967337.81.9244.973.581.34.718.99.14..73.78..9341..431..2971..9.7348.973.41.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A4: 6 => CTR => A4: 2,5
* DIS # C8: 5,6 => CTR => C8: 2
* DIS # B8: 2,6 => CTR => B8: 5
* DIS # D6: 2,5 => CTR => D6: 6
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* DIS # E7: 6 => CTR => E7: 5,8
* DIS # I6: 5,6 => CTR => I6: 2
* DIS # A4: 5,6 => CTR => A4: 2
* PRF # A4: 2 => SOL
* PRF # D4: 5,6 => SOL
* DIS # D4: 2 => CTR => D4: 5,6
* DIS # E7: 6 => CTR => E7: 5,8
* DIS # A7: 5,8 => CTR => A7: 6
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* DIS # I6: 5,6 => CTR => I6: 2
* CNT  17 HDP CHAINS /  31 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 # A4: 6 => CTR => A4: 2,5
* DIS A4: 2,5 # C6: 2 => CTR => C6: 5,6
* PRF A4: 2,5 + C6: 5,6 # D4: 2,5 => SOL
* STA A4: 2,5 + C6: 5,6 + D4: 2,5
* CNT   3 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

.1..4.67.3..8...........5......71...9......3...........4....2.....9....8..73..... initial
.18.4967337.81.9244.973.581.34.718.99.14..73.78..9341..431..2971..9.7348.973.41.. autosolve
518249673376815924429736581234571869961482735785693412643158297152967348897324156 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
A1: 2,5
C2: 5,6
B3: 2,6
D1: 2,5
F2: 5,6
F3: 2,6
E5: 5,8
H4: 5,6
A9: 2,8
F7: 5,8
E9: 2,8
H9: 5,6
I9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A1,B3: 2.. / A1 = 2  =>  0 pairs (X) / B3 = 2  =>  0 pairs (_)
D1,F3: 2.. / D1 = 2  =>  0 pairs (*) / F3 = 2  =>  0 pairs (X)
I5,I6: 2.. / I5 = 2  =>  0 pairs (X) / I6 = 2  => 17 pairs (_)
E8,E9: 2.. / E8 = 2  =>  0 pairs (X) / E9 = 2  => 13 pairs (_)
A1,D1: 2.. / A1 = 2  =>  0 pairs (X) / D1 = 2  =>  0 pairs (_)
B3,F3: 2.. / B3 = 2  =>  0 pairs (*) / F3 = 2  =>  0 pairs (X)
A4,D4: 2.. / A4 = 2  =>  0 pairs (*) / D4 = 2  =>  0 pairs (X)
A9,E9: 2.. / A9 = 2  =>  0 pairs (X) / E9 = 2  => 13 pairs (_)
C6,C8: 2.. / C6 = 2  =>  0 pairs (X) / C8 = 2  => 15 pairs (_)
F3,F5: 2.. / F3 = 2  =>  0 pairs (X) / F5 = 2  =>  0 pairs (_)
A1,C2: 5.. / A1 = 5  =>  0 pairs (*) / C2 = 5  =>  0 pairs (X)
D1,F2: 5.. / D1 = 5  =>  0 pairs (X) / F2 = 5  =>  0 pairs (_)
H9,I9: 5.. / H9 = 5  =>  0 pairs (*) / I9 = 5  =>  0 pairs (X)
A1,D1: 5.. / A1 = 5  =>  0 pairs (*) / D1 = 5  =>  0 pairs (X)
C2,F2: 5.. / C2 = 5  =>  0 pairs (X) / F2 = 5  =>  0 pairs (_)
B5,B8: 5.. / B5 = 5  =>  0 pairs (X) / B8 = 5  => 17 pairs (_)
H4,H9: 5.. / H4 = 5  => 14 pairs (_) / H9 = 5  =>  0 pairs (*)
C2,B3: 6.. / C2 = 6  =>  0 pairs (*) / B3 = 6  =>  0 pairs (X)
F2,F3: 6.. / F2 = 6  =>  0 pairs (X) / F3 = 6  =>  0 pairs (_)
D4,D6: 6.. / D4 = 6  =>  0 pairs (X) / D6 = 6  => 16 pairs (_)
E7,E8: 6.. / E7 = 6  =>  0 pairs (X) / E8 = 6  => 15 pairs (_)
H9,I9: 6.. / H9 = 6  => 14 pairs (_) / I9 = 6  =>  0 pairs (*)
C2,F2: 6.. / C2 = 6  =>  0 pairs (*) / F2 = 6  =>  0 pairs (X)
B3,F3: 6.. / B3 = 6  =>  0 pairs (X) / F3 = 6  =>  0 pairs (_)
B5,I5: 6.. / B5 = 6  =>  0 pairs (*) / I5 = 6  =>  0 pairs (X)
A7,E7: 6.. / A7 = 6  => 15 pairs (_) / E7 = 6  =>  0 pairs (X)
A4,A7: 6.. / A4 = 6  =>  0 pairs (X) / A7 = 6  => 15 pairs (_)
H4,H9: 6.. / H4 = 6  =>  0 pairs (*) / H9 = 6  =>  0 pairs (X)
E5,F5: 8.. / E5 = 8  => 13 pairs (_) / F5 = 8  =>  0 pairs (X)
A7,A9: 8.. / A7 = 8  =>  0 pairs (X) / A9 = 8  => 13 pairs (_)
A9,E9: 8.. / A9 = 8  => 13 pairs (_) / E9 = 8  =>  0 pairs (X)
F5,F7: 8.. / F5 = 8  =>  0 pairs (X) / F7 = 8  => 13 pairs (_)
* DURATION: 0:01:01.155703  START: 03:09:45.851597  END: 03:10:47.007300 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A9,B3,C2,D1,E5,E9,F2,F3,F7,H4,H9,I9)
* .18.4967337.81.9244.973.581.34.718.99.14..73.78..9341..431..2971..9.7348.973.41..
* PAIR A1: 2,5 COL A
A4: 2,5,6                                # reduction candidate for 2,5
A4: 6 => CTR
* .18.4967337.81.9244.973.5816342718599.14..73678.693412.4316.2971.2957348897324165
A4: 2,5                                  # 15 pairs
* PAIR C2: 5,6 COL C
C6: 5,6,2                                # reduction candidate for 5,6
C6: 5,6                                  # 15 pairs
C8: 5,6,2                                # reduction candidate for 5,6
C8: 5,6 => CTR
* 218549673375816924469732581.342718.99.14..732782693415.431..2971..9.7348.973.4156
C8: 2                                    # 15 pairs
* PAIR B3: 2,6 COL B
B5: 2,6,5                                # reduction candidate for 2,6
B5: 2,6                                  # 17 pairs
B8: 2,6,5                                # reduction candidate for 2,6
B8: 2,6 => CTR
* .1824967337581.9244.973.581.34.718.995148273678..93412.431.82971.2957348897324165
B8: 5                                    # 17 pairs
* PAIR D1: 2,5 COL D
D4: 2,5,6                                # reduction candidate for 2,5
D4: 2,5                                  # 16 pairs
D6: 2,5,6                                # reduction candidate for 2,5
D6: 2,5 => CTR
* 51824967337681592442973658123467185996145.73.78..9341.6431..2971..967348897324165
D6: 6                                    # 16 pairs
* PAIR E5: 5,8 BLK 5
F5: 5,8,2                                # reduction candidate for 5,8
F5: 5,8 => CTR
* 218549673375816924469732581.342718.99.14..73678.69341..431..2971..9.7348.973.41..
F5: 2 => SOLVED
* 518249673376815924429736581234571869961482735785693412643158297152967348897324156
* PAIR E5: 5,8 COL E
E7: 5,8,6                                # reduction candidate for 5,8
E7: 6 => CTR
* .18.4967337.81.9244.973.5816342718599.14..73678.693412.4316.2971.2957348897324165
E7: 5,8                                  # 15 pairs
* PAIR H4: 5,6 BLK 6
I5: 5,6,2                                # reduction candidate for 5,6
I5: 5,6                                  # 17 pairs
I6: 5,6,2                                # reduction candidate for 5,6
I6: 5,6 => CTR
* .18.4967337.81.9244.9732581.34.718.99614..73278..9341..431..2971..9.7348.973.41..
I6: 2                                    # 17 pairs
* PAIR H4: 5,6 ROW 4
A4: 5,6,2                                # reduction candidate for 5,6
A4: 5,6 => CTR
* 21854967337581692446973258163427185995148.73.78.69341..431..2971..9.7348.973.41..
A4: 2 => SOLVED
* 518249673376815924429736581234571869961482735785693412643158297152967348897324156
D4: 5,6,2                                # reduction candidate for 5,6
D4: 5,6 => SOLVED
* 518249673376815924429736581234571869961482735785693412643158297152967348897324156
D4: 2 => CTR
* 21854967337581692446973258163427185995148.73.78.69341..431..2971..9.7348.973.41..
* PAIR F7: 5,8 BLK 8
E7: 5,8,6                                # reduction candidate for 5,8
E7: 6 => CTR
* .18.4967337.81.9244.973.5816342718599.14..73678.693412.4316.2971.2957348897324165
E7: 5,8                                  # 15 pairs
* PAIR F7: 5,8 ROW 7
A7: 5,8,6                                # reduction candidate for 5,8
A7: 5,8 => CTR
* .18.4967337.81.9244.973.5816342718599.14..73678.693412.4316.2971.2957348897324165
A7: 6                                    # 15 pairs
* PAIR F7: 5,8 COL F
F5: 5,8,2                                # reduction candidate for 5,8
F5: 5,8 => CTR
* 218549673375816924469732581.342718.99.14..73678.69341..431..2971..9.7348.973.41..
F5: 2 => SOLVED
* 518249673376815924429736581234571869961482735785693412643158297152967348897324156
* PAIR I9: 5,6 COL I
I5: 5,6,2                                # reduction candidate for 5,6
I5: 5,6                                  # 17 pairs
I6: 5,6,2                                # reduction candidate for 5,6
I6: 5,6 => CTR
* .18.4967337.81.9244.9732581.34.718.99614..73278..9341..431..2971..9.7348.973.41..
I6: 2                                    # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-017-base-pr-000.dot
* REASONING
* DIS # A4: 6 => CTR => A4: 2,5
* DIS # C8: 5,6 => CTR => C8: 2
* DIS # B8: 2,6 => CTR => B8: 5
* DIS # D6: 2,5 => CTR => D6: 6
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* DIS # E7: 6 => CTR => E7: 5,8
* DIS # I6: 5,6 => CTR => I6: 2
* DIS # A4: 5,6 => CTR => A4: 2
* PRF # A4: 2 => SOL
* PRF # D4: 5,6 => SOL
* DIS # D4: 2 => CTR => D4: 5,6
* DIS # E7: 6 => CTR => E7: 5,8
* DIS # A7: 5,8 => CTR => A7: 6
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* DIS # I6: 5,6 => CTR => I6: 2
* CNT  17 HDP CHAINS /  31 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A9,B3,C2,D1,E5,E9,F2,F3,F7,H4,H9,I9)
* .18.4967337.81.9244.973.581.34.718.99.14..73.78..9341..431..2971..9.7348.973.41..
* PAIR A1: 2,5 COL A
A4: 2,5,6                                # reduction candidate for 2,5
A4: 6 => CTR
* .18.4967337.81.9244.973.5816342718599.14..73678.693412.4316.2971.2957348897324165
* PAIR RESTART
* PAIR C2: 5,6 COL C
C6: 5,6,2                                # reduction candidate for 5,6
C6: 2 => CTR
* .18.49673376815924429736581234.718.99.14..73.78..9341.6431..2971..9673488973241..
* PAIR RESTART
* PAIR D1: 2,5 COL D
D4: 2,5,6                                # reduction candidate for 2,5
D4: 2,5 => SOLVED
* 518249673376815924429736581234571869961482735785693412643158297152967348897324156
* DURATION: 0:00:06.715196  START: 03:11:22.643619  END: 03:11:29.358815 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-017-base-pr-001.dot
* REASONING
* DIS # A4: 6 => CTR => A4: 2,5
* DIS A4: 2,5 # C6: 2 => CTR => C6: 5,6
* PRF A4: 2,5 + C6: 5,6 # D4: 2,5 => SOL
* STA A4: 2,5 + C6: 5,6 + D4: 2,5
* CNT   3 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 017

solution: 518249673376815924429736581234571869961482735785693412643158297152967348897324156
info: 1310     FNBWXY   S8.f     47982

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

Solution

position: 518249673376815924429736581234571869961482735785693412643158297152967348897324156 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 # A4: 2,5 => UNS
* DIS # A4: 6 => CTR => A4: 2,5
* INC # C6: 5,6 => UNS
* DIS # C8: 5,6 => CTR => C8: 2
* INC # C8: 2 => UNS
* INC # B5: 2,6 => UNS
* DIS # B8: 2,6 => CTR => B8: 5
* INC # B8: 5 => UNS
* INC # D4: 2,5 => UNS
* DIS # D6: 2,5 => CTR => D6: 6
* INC # D6: 6 => UNS
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* INC # E7: 5,8 => UNS
* DIS # E7: 6 => CTR => E7: 5,8
* INC # I5: 5,6 => UNS
* DIS # I6: 5,6 => CTR => I6: 2
* INC # I6: 2 => UNS
* DIS # A4: 5,6 => CTR => A4: 2
* PRF # A4: 2 => SOL
* PRF # D4: 5,6 => SOL
* DIS # D4: 2 => CTR => D4: 5,6
* INC # E7: 5,8 => UNS
* DIS # E7: 6 => CTR => E7: 5,8
* DIS # A7: 5,8 => CTR => A7: 6
* INC # A7: 6 => UNS
* DIS # F5: 5,8 => CTR => F5: 2
* PRF # F5: 2 => SOL
* INC # I5: 5,6 => UNS
* DIS # I6: 5,6 => CTR => I6: 2
* INC # I6: 2 => UNS
* CNT  31 HDP CHAINS /  31 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A4: 2,5 => UNS
* DIS # A4: 6 => CTR => A4: 2,5
* INC A4: 2,5 # C6: 5,6 => UNS
* DIS A4: 2,5 # C6: 2 => CTR => C6: 5,6
* PRF A4: 2,5 + C6: 5,6 # D4: 2,5 => SOL
* STA A4: 2,5 + C6: 5,6 + D4: 2,5
* CNT   5 HDP CHAINS /   5 HYP OPENED