Analysis of xx-top500-415-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ......6.23..8........2..5..2..3...4..67.......1...........761..8......3.......... initial

Autosolve

position: 1..7..6.232.86....67.2..5.32..3...46.67...3...136..8...324761.88.61...3.7.1...26. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C1: 5,9 => CTR => C1: 4,8
* DIS # F2: 5,9 => CTR => F2: 1
* PRF # F2: 1 => SOL
* DIS # C4: 8 => CTR => C4: 5,9
* DIS # H3: 8,9 => CTR => H3: 1
* PRF # H3: 1 => SOL
* DIS # C1: 8,9 => CTR => C1: 4,5
* DIS # E4: 5,9 => CTR => E4: 1
* DIS # E5: 5,9 => CTR => E5: 2,4,8
* DIS # F5: 5,9 => CTR => F5: 2,4,8
* DIS # E6: 5,9 => CTR => E6: 2,4
* DIS # F6: 5,9 => CTR => F6: 2,4,7
* DIS # H5: 5,9 => CTR => H5: 1,2
* DIS # I5: 5,9 => CTR => I5: 1
* PRF # H6: 7,9 => SOL
* DIS # F4: 7,9 => CTR => F4: 1,5
* DIS # I8: 5,9 => CTR => I8: 4,7
* DIS # H5: 5,9 => CTR => H5: 1,2
* PRF # H6: 5,9 => SOL
* CNT  19 HDP CHAINS /  50 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 # C1: 5,9 => CTR => C1: 4,8
* DIS C1: 4,8 # B1: 8 => CTR => B1: 5,9
* DIS C1: 4,8 + B1: 5,9 # F2: 5,9 => CTR => F2: 1
* PRF C1: 4,8 + B1: 5,9 + F2: 1 => SOL
* STA C1: 4,8 + B1: 5,9 + F2: 1
* CNT   4 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

......6.23..8........2..5..2..3...4..67.......1...........761..8......3.......... initial
1..7..6.232.86....67.2..5.32..3...46.67...3...136..8...324761.88.61...3.7.1...26. autosolve
194753682325861974678249513289315746567984321413627895932476158856192437741538269 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
C2: 5,9
H1: 8,9
D5: 5,9
G4: 7,9
A7: 5,9
D9: 5,9
E9: 3,8
F9: 3,8
H7: 5,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E4,F4: 1.. / E4 = 1  => 10 pairs (_) / F4 = 1  =>  0 pairs (X)
H5,I5: 1.. / H5 = 1  =>  0 pairs (X) / I5 = 1  =>  9 pairs (_)
E3,E4: 1.. / E3 = 1  =>  0 pairs (X) / E4 = 1  => 10 pairs (_)
I2,I5: 1.. / I2 = 1  =>  0 pairs (X) / I5 = 1  =>  9 pairs (_)
H5,H6: 2.. / H5 = 2  => 10 pairs (_) / H6 = 2  => 13 pairs (_)
E8,F8: 2.. / E8 = 2  => 10 pairs (_) / F8 = 2  => 10 pairs (_)
E1,F1: 3.. / E1 = 3  =>  8 pairs (_) / F1 = 3  =>  7 pairs (_)
E9,F9: 3.. / E9 = 3  =>  7 pairs (_) / F9 = 3  =>  8 pairs (_)
E1,E9: 3.. / E1 = 3  =>  8 pairs (_) / E9 = 3  =>  7 pairs (_)
F1,F9: 3.. / F1 = 3  =>  7 pairs (_) / F9 = 3  =>  8 pairs (_)
C1,C3: 4.. / C1 = 4  => 10 pairs (_) / C3 = 4  =>  0 pairs (X)
G2,I2: 4.. / G2 = 4  => 10 pairs (_) / I2 = 4  => 13 pairs (_)
A5,A6: 4.. / A5 = 4  => 10 pairs (_) / A6 = 4  => 13 pairs (_)
B8,B9: 4.. / B8 = 4  => 11 pairs (_) / B9 = 4  => 13 pairs (_)
B9,I9: 4.. / B9 = 4  => 13 pairs (_) / I9 = 4  => 11 pairs (_)
G2,G8: 4.. / G2 = 4  => 10 pairs (_) / G8 = 4  => 13 pairs (_)
C2,F2: 5.. / C2 = 5  => 14 pairs (_) / F2 = 5  =>  0 pairs (X)
A7,H7: 5.. / A7 = 5  =>  0 pairs (X) / H7 = 5  =>  0 pairs (_)
D5,D9: 5.. / D5 = 5  =>  0 pairs (X) / D9 = 5  => 16 pairs (_)
F4,F6: 7.. / F4 = 7  =>  0 pairs (X) / F6 = 7  => 12 pairs (_)
G8,I8: 7.. / G8 = 7  =>  0 pairs (X) / I8 = 7  => 11 pairs (_)
F4,G4: 7.. / F4 = 7  =>  0 pairs (X) / G4 = 7  => 12 pairs (_)
H2,H6: 7.. / H2 = 7  => 10 pairs (_) / H6 = 7  =>  0 pairs (X)
H1,H3: 8.. / H1 = 8  => 11 pairs (_) / H3 = 8  =>  0 pairs (X)
B4,C4: 8.. / B4 = 8  => 13 pairs (_) / C4 = 8  =>  0 pairs (X)
E5,F5: 8.. / E5 = 8  =>  7 pairs (_) / F5 = 8  =>  8 pairs (_)
E9,F9: 8.. / E9 = 8  =>  8 pairs (_) / F9 = 8  =>  7 pairs (_)
C3,H3: 8.. / C3 = 8  => 11 pairs (_) / H3 = 8  =>  0 pairs (X)
B1,B4: 8.. / B1 = 8  =>  0 pairs (X) / B4 = 8  => 13 pairs (_)
E5,E9: 8.. / E5 = 8  =>  7 pairs (_) / E9 = 8  =>  8 pairs (_)
F5,F9: 8.. / F5 = 8  =>  8 pairs (_) / F9 = 8  =>  7 pairs (_)
A7,H7: 9.. / A7 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
D5,D9: 9.. / D5 = 9  => 16 pairs (_) / D9 = 9  =>  0 pairs (X)
* DURATION: 0:00:59.467965  START: 17:00:39.243309  END: 17:01:38.711274 2017-05-04
* CP COUNT: (33)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,C2,D5,D9,E9,F9,G4,H1,H7)
* 1..7..6.232.86....67.2..5.32..3...46.67...3...136..8...324761.88.61...3.7.1...26.
* PAIR C2: 5,9 BLK 1
B1: 5,9,8                                # reduction candidate for 5,9
B1: 5,9                                  # 13 pairs
C1: 5,9,4,8                              # reduction candidate for 5,9
C1: 5,9 => CTR
* 1857..692329865...6742..583298351746.679..3...136.78299324761588561..93.7.1...26.
C1: 4,8                                  # 10 pairs
* PAIR C2: 5,9 ROW 2
F2: 5,9,1                                # reduction candidate for 5,9
F2: 5,9 => CTR
* 1..7..6.232.86.47167.2..5.32..3..746.675..3195136.782.9324761588.61..9377.19..264
F2: 1 => SOLVED
* 194753682325861974678249513289315746567984321413627895932476158856192437741538269
* PAIR C2: 5,9 COL C
C4: 5,9,8                                # reduction candidate for 5,9
C4: 8 => CTR
* 18.7..69232.86.47167.2..5832983..746.675..3195136.782.9324761588.61..9377.19..264
C4: 5,9                                  # 13 pairs
* PAIR H1: 8,9 BLK 3
H3: 8,9,1                                # reduction candidate for 8,9
H3: 8,9 => CTR
* 1..7..6.232.86.47167.2..5.32..3..746.675..3195136.782.9324761588.61..9377.19..264
H3: 1 => SOLVED
* 194753682325861974678249513289315746567984321413627895932476158856192437741538269
* PAIR H1: 8,9 ROW 1
B1: 8,9,5                                # reduction candidate for 8,9
B1: 8,9                                  # 12 pairs
C1: 8,9,4,5                              # reduction candidate for 8,9
C1: 8,9 => CTR
* 1..7..692329865...6742..5832.53...46.67...3...136..8...324761.88.61...3.7.1...26.
C1: 4,5                                  # 10 pairs
* PAIR D5: 5,9 BLK 5
E4: 5,9,1                                # reduction candidate for 5,9
E4: 5,9 => CTR
* 1..7..6.232.86.47167.21.5.32..3.1746.675..3195136.782.9324761588461..9377519..264
E4: 1                                    # 10 pairs
F4: 5,9,1,7                              # reduction candidate for 5,9
F4: 5,9                                  # 14 pairs
E5: 5,9,2,4,8                            # reduction candidate for 5,9
E5: 5,9 => CTR
* 1..73.68232.86...96782..5132853...46467..83219136..8..5324761988.61...3.7.1.8326.
E5: 2,4,8                                #  9 pairs
F5: 5,9,2,4,8                            # reduction candidate for 5,9
F5: 5,9 => CTR
* 1..7.368232.86...96782..5132853...46467.8.3219136..8..5324761988.61...3.7.1.3826.
F5: 2,4,8                                #  9 pairs
E6: 5,9,2,4                              # reduction candidate for 5,9
E6: 5,9 => CTR
* 1..7..68232.86...96782..513285317946.67...3...136..8..5324761988.61...3.7.1...26.
E6: 2,4                                  # 10 pairs
F6: 5,9,2,4,7                            # reduction candidate for 5,9
F6: 5,9 => CTR
* 1..7..68232.86...96782..513285317946.67...3...136..8..5324761988.61...3.7.1...26.
F6: 2,4,7                                #  9 pairs
* PAIR D5: 5,9 ROW 5
A5: 5,9,4                                # reduction candidate for 5,9
A5: 5,9                                  # 13 pairs
H5: 5,9,1,2                              # reduction candidate for 5,9
H5: 5,9 => CTR
* 1.47..682325861.7.6782..513289315746.679..3515136..82..324761.88.61...3.7.1...26.
H5: 1,2                                  # 10 pairs
I5: 5,9,1                                # reduction candidate for 5,9
I5: 5,9 => CTR
* 1..7..6.232.86.47167.2..5.32..3..746.675..3195136.782.9324761588.61..9377.19..264
I5: 1                                    #  9 pairs
* PAIR G4: 7,9 BLK 6
H6: 7,9,2,5                              # reduction candidate for 7,9
H6: 7,9 => SOLVED
* 194753682325861974678249513289315746567984321413627895932476158856192437741538269
H6: 2,5                                  # 11 pairs
I6: 7,9,5                                # reduction candidate for 7,9
I6: 7,9                                  # 13 pairs
* PAIR G4: 7,9 ROW 4
F4: 7,9,1,5                              # reduction candidate for 7,9
F4: 7,9 => CTR
* 1..7..68232.86....6782..51328531..46.67...3.1.136..8..5324761988.61...3.7.1...26.
F4: 1,5                                  # 13 pairs
* PAIR G4: 7,9 COL G
G2: 7,9,4                                # reduction candidate for 7,9
G2: 7,9                                  # 13 pairs
G8: 7,9,4                                # reduction candidate for 7,9
G8: 7,9                                  # 10 pairs
* PAIR A7: 5,9 BLK 7
B8: 5,9,4                                # reduction candidate for 5,9
B8: 5,9                                  # 13 pairs
B9: 5,9,4                                # reduction candidate for 5,9
B9: 5,9                                  # 11 pairs
* PAIR A7: 5,9 COL A
A5: 5,9,4                                # reduction candidate for 5,9
A5: 5,9                                  # 13 pairs
A6: 5,9,4                                # reduction candidate for 5,9
A6: 5,9                                  # 10 pairs
* PAIR D9: 5,9 BLK 8
E8: 5,9,2                                # reduction candidate for 5,9
E8: 5,9                                  # 10 pairs
F8: 5,9,2                                # reduction candidate for 5,9
F8: 5,9                                  # 10 pairs
* PAIR D9: 5,9 ROW 9
B9: 5,9,4                                # reduction candidate for 5,9
B9: 5,9                                  # 11 pairs
I9: 5,9,4                                # reduction candidate for 5,9
I9: 5,9                                  # 13 pairs
* PAIR H7: 5,9 BLK 9
I8: 5,9,4,7                              # reduction candidate for 5,9
I8: 5,9 => CTR
* 1..7..68232.86.4.96782..513285317946.67...3...136..8..5324761988461..7357915..264
I8: 4,7                                  # 10 pairs
I9: 5,9,4                                # reduction candidate for 5,9
I9: 5,9                                  # 13 pairs
* PAIR H7: 5,9 COL H
H5: 5,9,1,2                              # reduction candidate for 5,9
H5: 5,9 => CTR
* 1.47..682325861.7.6782..513289315746.679..3515136..82..324761.88.61...3.7.1...26.
H5: 1,2                                  # 10 pairs
H6: 5,9,2,7                              # reduction candidate for 5,9
H6: 5,9 => SOLVED
* 194753682325861974678249513289315746567984321413627895932476158856192437741538269
H6: 2,7                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-415-base-pr-000.dot
* REASONING
* DIS # C1: 5,9 => CTR => C1: 4,8
* DIS # F2: 5,9 => CTR => F2: 1
* PRF # F2: 1 => SOL
* DIS # C4: 8 => CTR => C4: 5,9
* DIS # H3: 8,9 => CTR => H3: 1
* PRF # H3: 1 => SOL
* DIS # C1: 8,9 => CTR => C1: 4,5
* DIS # E4: 5,9 => CTR => E4: 1
* DIS # E5: 5,9 => CTR => E5: 2,4,8
* DIS # F5: 5,9 => CTR => F5: 2,4,8
* DIS # E6: 5,9 => CTR => E6: 2,4
* DIS # F6: 5,9 => CTR => F6: 2,4,7
* DIS # H5: 5,9 => CTR => H5: 1,2
* DIS # I5: 5,9 => CTR => I5: 1
* PRF # H6: 7,9 => SOL
* DIS # F4: 7,9 => CTR => F4: 1,5
* DIS # I8: 5,9 => CTR => I8: 4,7
* DIS # H5: 5,9 => CTR => H5: 1,2
* PRF # H6: 5,9 => SOL
* CNT  19 HDP CHAINS /  50 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,C2,D5,D9,E9,F9,G4,H1,H7)
* 1..7..6.232.86....67.2..5.32..3...46.67...3...136..8...324761.88.61...3.7.1...26.
* PAIR C2: 5,9 BLK 1
B1: 5,9,8                                # reduction candidate for 5,9
B1: 5,9                                  # 13 pairs
C1: 5,9,4,8                              # reduction candidate for 5,9
C1: 5,9 => CTR
* 1857..692329865...6742..583298351746.679..3...136.78299324761588561..93.7.1...26.
* RESTART
* PAIR C2: 5,9 BLK 1
B1: 5,9,8                                # reduction candidate for 5,9
B1: 8 => CTR
* 1847..6923258694716792..5832983..746.675..3195136.782.9324761588.61..9377.19..264
* PAIR C2: 5,9 ROW 2
F2: 5,9,1                                # reduction candidate for 5,9
F2: 5,9 => CTR
* 1947..6823258694716782..5932893..746.675..3195136.782.9324761588.61..9377.19..264
F2: 1 => SOLVED
* 194753682325861974678249513289315746567984321413627895932476158856192437741538269
* DURATION: 0:00:07.960204  START: 17:02:28.824258  END: 17:02:36.784462 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-415-base-pr-001.dot
* REASONING
* DIS # C1: 5,9 => CTR => C1: 4,8
* DIS C1: 4,8 # B1: 8 => CTR => B1: 5,9
* DIS C1: 4,8 + B1: 5,9 # F2: 5,9 => CTR => F2: 1
* PRF C1: 4,8 + B1: 5,9 + F2: 1 => SOL
* STA C1: 4,8 + B1: 5,9 + F2: 1
* CNT   4 HDP CHAINS /   5 HYP OPENED

Header Info

Top 500 Minimum 17 415

solution: 194753682325861974678249513289315746567984321413627895932476158856192437741538269
info: 95067    FNBHYK   S8.f     1458

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

Solution

position: 194753682325861974678249513289315746567984321413627895932476158856192437741538269 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 # B1: 5,9 => UNS
* DIS # C1: 5,9 => CTR => C1: 4,8
* INC # C1: 4,8 => UNS
* DIS # F2: 5,9 => CTR => F2: 1
* PRF # F2: 1 => SOL
* INC # C4: 5,9 => UNS
* DIS # C4: 8 => CTR => C4: 5,9
* DIS # H3: 8,9 => CTR => H3: 1
* PRF # H3: 1 => SOL
* INC # B1: 8,9 => UNS
* DIS # C1: 8,9 => CTR => C1: 4,5
* INC # C1: 4,5 => UNS
* DIS # E4: 5,9 => CTR => E4: 1
* INC # E4: 1 => UNS
* INC # F4: 5,9 => UNS
* DIS # E5: 5,9 => CTR => E5: 2,4,8
* INC # E5: 2,4,8 => UNS
* DIS # F5: 5,9 => CTR => F5: 2,4,8
* INC # F5: 2,4,8 => UNS
* DIS # E6: 5,9 => CTR => E6: 2,4
* INC # E6: 2,4 => UNS
* DIS # F6: 5,9 => CTR => F6: 2,4,7
* INC # F6: 2,4,7 => UNS
* INC # A5: 5,9 => UNS
* DIS # H5: 5,9 => CTR => H5: 1,2
* INC # H5: 1,2 => UNS
* DIS # I5: 5,9 => CTR => I5: 1
* INC # I5: 1 => UNS
* PRF # H6: 7,9 => SOL
* INC # H6: 2,5 => UNS
* INC # I6: 7,9 => UNS
* DIS # F4: 7,9 => CTR => F4: 1,5
* INC # F4: 1,5 => UNS
* INC # G2: 7,9 => UNS
* INC # G8: 7,9 => UNS
* INC # B8: 5,9 => UNS
* INC # B9: 5,9 => UNS
* INC # A5: 5,9 => UNS
* INC # A6: 5,9 => UNS
* INC # E8: 5,9 => UNS
* INC # F8: 5,9 => UNS
* INC # B9: 5,9 => UNS
* INC # I9: 5,9 => UNS
* DIS # I8: 5,9 => CTR => I8: 4,7
* INC # I8: 4,7 => UNS
* INC # I9: 5,9 => UNS
* DIS # H5: 5,9 => CTR => H5: 1,2
* INC # H5: 1,2 => UNS
* PRF # H6: 5,9 => SOL
* INC # H6: 2,7 => UNS
* CNT  50 HDP CHAINS /  50 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B1: 5,9 => UNS
* DIS # C1: 5,9 => CTR => C1: 4,8
* INC C1: 4,8 # B1: 5,9 => UNS
* DIS C1: 4,8 # B1: 8 => CTR => B1: 5,9
* DIS C1: 4,8 + B1: 5,9 # F2: 5,9 => CTR => F2: 1
* PRF C1: 4,8 + B1: 5,9 + F2: 1 => SOL
* STA C1: 4,8 + B1: 5,9 + F2: 1
* CNT   6 HDP CHAINS /   5 HYP OPENED