Analysis of xx-top500-048-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .9...7..1.62.........3..........25..8.....3......6..8.....4..2.5..8.....3........ initial

Autosolve

position: 493257861.624.8.35...3.62..93.1825.68.6.743.22...63.8.6..745.2352.83.6..3..62..58 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I3: 7,9 => CTR => I3: 4
* DIS # G6: 7,9 => CTR => G6: 1,4
* DIS # G9: 7,9 => CTR => G9: 1,4
* PRF # C9: 4,7 => SOL
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* PRF # H8: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* PRF # H8: 4,7 => SOL
* DIS # C7: 9 => CTR => C7: 1,8
* PRF # C9: 4,7 => SOL
* PRF # G9: 1,9 => SOL
* PRF # C8: 1,9 => SOL
* PRF # G9: 1,9 => SOL
* PRF # G9: 1,9 => SOL
* DIS # C7: 1,9 => CTR => C7: 8
* PRF # C7: 8 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* CNT  26 HDP CHAINS /  45 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: 7,9 => CTR => I3: 4
* DIS I3: 4 # G6: 7,9 => CTR => G6: 1,4
* DIS I3: 4 + G6: 1,4 # G9: 7,9 => CTR => G9: 1,4
* PRF I3: 4 + G6: 1,4 + G9: 1,4 => SOL
* STA I3: 4 + G6: 1,4 + G9: 1,4
* CNT   4 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.9...7..1.62.........3..........25..8.....3......6..8.....4..2.5..8.....3........ initial
493257861.624.8.35...3.62..93.1825.68.6.743.22...63.8.6..745.2352.83.6..3..62..58 autosolve
493257861162498735785316294934182576856974312271563489618745923529831647347629158 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (20)
A2: 1,7
A3: 1,7
B3: 5,8
C3: 5,8
E2: 1,9
E3: 1,9
G2: 7,9
C4: 4,7
B5: 1,5
B6: 4,7
C6: 1,5
D5: 5,9
D6: 5,9
H4: 4,7
H5: 1,9
B7: 1,8
B9: 4,7
F8: 1,9
F9: 1,9
G7: 1,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,A3: 1.. / A2 = 1  => 17 pairs (_) / A3 = 1  =>  0 pairs (X)
E2,E3: 1.. / E2 = 1  =>  0 pairs (X) / E3 = 1  => 17 pairs (_)
B5,C6: 1.. / B5 = 1  =>  0 pairs (X) / C6 = 1  =>  0 pairs (_)
H5,G6: 1.. / H5 = 1  =>  0 pairs (*) / G6 = 1  =>  0 pairs (X)
F8,F9: 1.. / F8 = 1  =>  0 pairs (*) / F9 = 1  =>  0 pairs (X)
A2,E2: 1.. / A2 = 1  => 17 pairs (_) / E2 = 1  =>  0 pairs (X)
A3,E3: 1.. / A3 = 1  =>  0 pairs (X) / E3 = 1  => 17 pairs (_)
B5,H5: 1.. / B5 = 1  =>  0 pairs (X) / H5 = 1  =>  0 pairs (_)
C6,G6: 1.. / C6 = 1  =>  0 pairs (*) / G6 = 1  =>  0 pairs (X)
B5,B7: 1.. / B5 = 1  =>  0 pairs (X) / B7 = 1  =>  0 pairs (_)
H5,H8: 1.. / H5 = 1  =>  0 pairs (*) / H8 = 1  =>  0 pairs (X)
H3,I3: 4.. / H3 = 4  =>  0 pairs (X) / I3 = 4  => 23 pairs (_)
C4,B6: 4.. / C4 = 4  =>  0 pairs (*) / B6 = 4  =>  0 pairs (X)
C4,H4: 4.. / C4 = 4  =>  0 pairs (*) / H4 = 4  =>  0 pairs (X)
B6,B9: 4.. / B6 = 4  => 20 pairs (_) / B9 = 4  =>  0 pairs (*)
G6,G9: 4.. / G6 = 4  =>  0 pairs (*) / G9 = 4  =>  0 pairs (X)
B3,C3: 5.. / B3 = 5  =>  0 pairs (X) / C3 = 5  =>  0 pairs (_)
B5,C6: 5.. / B5 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
D5,D6: 5.. / D5 = 5  =>  0 pairs (X) / D6 = 5  =>  0 pairs (_)
B5,D5: 5.. / B5 = 5  =>  0 pairs (*) / D5 = 5  =>  0 pairs (X)
C6,D6: 5.. / C6 = 5  =>  0 pairs (X) / D6 = 5  =>  0 pairs (_)
B3,B5: 5.. / B3 = 5  =>  0 pairs (X) / B5 = 5  =>  0 pairs (_)
C3,C6: 5.. / C3 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
A2,A3: 7.. / A2 = 7  =>  0 pairs (X) / A3 = 7  => 17 pairs (_)
C4,B6: 7.. / C4 = 7  => 20 pairs (_) / B6 = 7  =>  0 pairs (*)
A2,G2: 7.. / A2 = 7  =>  0 pairs (X) / G2 = 7  => 17 pairs (_)
C4,H4: 7.. / C4 = 7  => 20 pairs (_) / H4 = 7  =>  0 pairs (*)
B6,B9: 7.. / B6 = 7  =>  0 pairs (*) / B9 = 7  =>  0 pairs (X)
B3,C3: 8.. / B3 = 8  =>  0 pairs (*) / C3 = 8  =>  0 pairs (X)
B7,C7: 8.. / B7 = 8  =>  0 pairs (X) / C7 = 8  =>  0 pairs (_)
B3,B7: 8.. / B3 = 8  =>  0 pairs (*) / B7 = 8  =>  0 pairs (X)
C3,C7: 8.. / C3 = 8  =>  0 pairs (X) / C7 = 8  =>  0 pairs (_)
E2,E3: 9.. / E2 = 9  => 17 pairs (_) / E3 = 9  =>  0 pairs (X)
D5,D6: 9.. / D5 = 9  =>  0 pairs (*) / D6 = 9  =>  0 pairs (X)
F8,F9: 9.. / F8 = 9  => 19 pairs (_) / F9 = 9  =>  0 pairs (*)
E2,G2: 9.. / E2 = 9  => 17 pairs (_) / G2 = 9  =>  0 pairs (X)
D5,H5: 9.. / D5 = 9  =>  0 pairs (*) / H5 = 9  =>  0 pairs (X)
C7,G7: 9.. / C7 = 9  =>  0 pairs (X) / G7 = 9  => 21 pairs (_)
* DURATION: 0:01:07.443038  START: 04:18:12.082782  END: 04:19:19.525820 2017-05-04
* CP COUNT: (38)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,B3,B5,B6,B7,B9,C3,C4,C6,D5,D6,E2,E3,F8,F9,G2,G7,H4,H5)
* 493257861.624.8.35...3.62..93.1825.68.6.743.22...63.8.6..745.2352.83.6..3..62..58
* PAIR G2: 7,9 BLK 3
H3: 7,9,4                                # reduction candidate for 7,9
H3: 7,9                                  # 23 pairs
I3: 7,9,4                                # reduction candidate for 7,9
I3: 7,9 => CTR
* 4932578617624189351..3962479341825768.6.743.227..634896.9745123527831694341629758
I3: 4                                    # 23 pairs
* PAIR G2: 7,9 COL G
G6: 7,9,1,4                              # reduction candidate for 7,9
G6: 7,9 => CTR
* 493257861.624.8.35...3.62..93.1825.68.6.743122.1563.8.61874592352.83.6..3..62..58
G6: 1,4                                  # 21 pairs
G9: 7,9,1,4                              # reduction candidate for 7,9
G9: 7,9 => CTR
* 493257861.624.8.35...3.62..9341825768165743922...6348.6..74512352.83.6..34.62..58
G9: 1,4                                  # 21 pairs
* PAIR C4: 4,7 COL C
C8: 4,7,1,9                              # reduction candidate for 4,7
C8: 4,7                                  # 23 pairs
C9: 4,7,1,9                              # reduction candidate for 4,7
C9: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
C9: 1,9                                  # 23 pairs
* PAIR B6: 4,7 ROW 6
G6: 4,7,1,9                              # reduction candidate for 4,7
G6: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
G6: 1,9 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
I6: 4,7,9                                # reduction candidate for 4,7
I6: 4,7 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
I6: 9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* PAIR H4: 4,7 BLK 6
G6: 4,7,1,9                              # reduction candidate for 4,7
G6: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
G6: 1,9 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
I6: 4,7,9                                # reduction candidate for 4,7
I6: 4,7 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
I6: 9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* PAIR H4: 4,7 COL H
H3: 4,7,9                                # reduction candidate for 4,7
H3: 4,7                                  # 26 pairs
H8: 4,7,1,9                              # reduction candidate for 4,7
H8: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
H8: 1,9                                  # 26 pairs
* PAIR H5: 1,9 BLK 6
G6: 1,9,4,7                              # reduction candidate for 1,9
G6: 1,9 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
G6: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* PAIR H5: 1,9 COL H
H8: 1,9,4,7                              # reduction candidate for 1,9
H8: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
H8: 1,9                                  # 26 pairs
* PAIR B7: 1,8 BLK 7
C7: 1,8,9                                # reduction candidate for 1,8
C7: 9 => CTR
* 493257861.624.8.35..83.62..93.1825.68.6.743.22.596318.6..745.2352.83.6..3..62..58
C7: 1,8                                  # 21 pairs
* PAIR B9: 4,7 BLK 7
C8: 4,7,1,9                              # reduction candidate for 4,7
C8: 4,7                                  # 23 pairs
C9: 4,7,1,9                              # reduction candidate for 4,7
C9: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
C9: 1,9                                  # 23 pairs
* PAIR B9: 4,7 ROW 9
G9: 4,7,1,9                              # reduction candidate for 4,7
G9: 1,9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
G9: 4,7                                  # 23 pairs
* PAIR F8: 1,9 ROW 8
C8: 1,9,4,7                              # reduction candidate for 1,9
C8: 1,9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
C8: 4,7                                  # 23 pairs
H8: 1,9,4,7                              # reduction candidate for 1,9
H8: 1,9                                  # 26 pairs
* PAIR F9: 1,9 ROW 9
C9: 1,9,4,7                              # reduction candidate for 1,9
C9: 1,9                                  # 23 pairs
G9: 1,9,4,7                              # reduction candidate for 1,9
G9: 1,9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
G9: 4,7                                  # 23 pairs
* PAIR G7: 1,9 BLK 9
H8: 1,9,4,7                              # reduction candidate for 1,9
H8: 1,9                                  # 26 pairs
G9: 1,9,4,7                              # reduction candidate for 1,9
G9: 1,9 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
G9: 4,7                                  # 23 pairs
* PAIR G7: 1,9 ROW 7
C7: 1,9,8                                # reduction candidate for 1,9
C7: 1,9 => CTR
* 493257861.624987357583162.993.182576816.743.22.596318.68174592352.83.61.3..621458
C7: 8 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* PAIR G7: 1,9 COL G
G6: 1,9,4,7                              # reduction candidate for 1,9
G6: 1,9 => CTR
* 4932578611624987357..3162949371825468.6974312241.63.876..745.2352483.67937.629458
G6: 4,7 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-048-base-pr-000.dot
* REASONING
* DIS # I3: 7,9 => CTR => I3: 4
* DIS # G6: 7,9 => CTR => G6: 1,4
* DIS # G9: 7,9 => CTR => G9: 1,4
* PRF # C9: 4,7 => SOL
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* PRF # H8: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* PRF # H8: 4,7 => SOL
* DIS # C7: 9 => CTR => C7: 1,8
* PRF # C9: 4,7 => SOL
* PRF # G9: 1,9 => SOL
* PRF # C8: 1,9 => SOL
* PRF # G9: 1,9 => SOL
* PRF # G9: 1,9 => SOL
* DIS # C7: 1,9 => CTR => C7: 8
* PRF # C7: 8 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* CNT  26 HDP CHAINS /  45 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,B3,B5,B6,B7,B9,C3,C4,C6,D5,D6,E2,E3,F8,F9,G2,G7,H4,H5)
* 493257861.624.8.35...3.62..93.1825.68.6.743.22...63.8.6..745.2352.83.6..3..62..58
* PAIR G2: 7,9 BLK 3
H3: 7,9,4                                # reduction candidate for 7,9
H3: 7,9                                  # 23 pairs
I3: 7,9,4                                # reduction candidate for 7,9
I3: 7,9 => CTR
* 4932578617624189351..3962479341825768.6.743.227..634896.9745123527831694341629758
* RESTART
* PAIR G2: 7,9 COL G
G6: 7,9,1,4                              # reduction candidate for 7,9
G6: 7,9 => CTR
* 493257861.624.8.35...3.62.493.1825468.6.74312241563.8.61874592352.83.6..3..62..58
G9: 7,9,1,4                              # reduction candidate for 7,9
G9: 7,9 => CTR
* 493257861.624.8.35...3.62.49341825768165743922...6348.6..74512352.83.64.34.62..58
G9: 1,4 => SOLVED
* 493257861162498735785316294934182576856974312271563489618745923529831647347629158
* DURATION: 0:00:05.132463  START: 04:20:08.677542  END: 04:20:13.810005 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-048-base-pr-001.dot
* REASONING
* DIS # I3: 7,9 => CTR => I3: 4
* DIS I3: 4 # G6: 7,9 => CTR => G6: 1,4
* DIS I3: 4 + G6: 1,4 # G9: 7,9 => CTR => G9: 1,4
* PRF I3: 4 + G6: 1,4 + G9: 1,4 => SOL
* STA I3: 4 + G6: 1,4 + G9: 1,4
* CNT   4 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 048

solution: 493257861162498735785316294934182576856974312271563489618745923529831647347629158
info: 1378     FNBTHWXY S8.f     46142

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

Solution

position: 493257861162498735785316294934182576856974312271563489618745923529831647347629158 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 # H3: 7,9 => UNS
* DIS # I3: 7,9 => CTR => I3: 4
* INC # I3: 4 => UNS
* DIS # G6: 7,9 => CTR => G6: 1,4
* INC # G6: 1,4 => UNS
* DIS # G9: 7,9 => CTR => G9: 1,4
* INC # G9: 1,4 => UNS
* INC # C8: 4,7 => UNS
* PRF # C9: 4,7 => SOL
* INC # C9: 1,9 => UNS
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* PRF # G6: 4,7 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* DIS # I6: 4,7 => CTR => I6: 9
* PRF # I6: 9 => SOL
* INC # H3: 4,7 => UNS
* PRF # H8: 4,7 => SOL
* INC # H8: 1,9 => UNS
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* INC # H8: 1,9 => UNS
* PRF # H8: 4,7 => SOL
* INC # C7: 1,8 => UNS
* DIS # C7: 9 => CTR => C7: 1,8
* INC # C8: 4,7 => UNS
* PRF # C9: 4,7 => SOL
* INC # C9: 1,9 => UNS
* INC # G9: 4,7 => UNS
* PRF # G9: 1,9 => SOL
* PRF # C8: 1,9 => SOL
* INC # C8: 4,7 => UNS
* INC # H8: 1,9 => UNS
* INC # C9: 1,9 => UNS
* PRF # G9: 1,9 => SOL
* INC # G9: 4,7 => UNS
* INC # H8: 1,9 => UNS
* PRF # G9: 1,9 => SOL
* INC # G9: 4,7 => UNS
* DIS # C7: 1,9 => CTR => C7: 8
* PRF # C7: 8 => SOL
* DIS # G6: 1,9 => CTR => G6: 4,7
* PRF # G6: 4,7 => SOL
* CNT  45 HDP CHAINS /  45 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # H3: 7,9 => UNS
* DIS # I3: 7,9 => CTR => I3: 4
* DIS I3: 4 # G6: 7,9 => CTR => G6: 1,4
* DIS I3: 4 + G6: 1,4 # G9: 7,9 => CTR => G9: 1,4
* PRF I3: 4 + G6: 1,4 + G9: 1,4 => SOL
* STA I3: 4 + G6: 1,4 + G9: 1,4
* CNT   5 HDP CHAINS /   4 HYP OPENED