Analysis of xx-top500-308-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....2...18.4......3...........6.8.4..2....7.....3.....6..4...8..7..1.5........... initial

Autosolve

position: ....2...18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7..1.5........... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # H8: 3,6 => CTR => H8: 9
* DIS # H9: 3,6 => CTR => H9: 1,7,9
* CNT   2 HDP CHAINS /   9 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 # H8: 3,6 => CTR => H8: 9
* DIS H8: 9 # H9: 3,6 => CTR => H9: 1,7
* DIS H8: 9 + H9: 1,7 # H1: 5 => CTR => H1: 3,6
* DIS H8: 9 + H9: 1,7 + H1: 3,6 # G1: 3,6 => CTR => G1: 4,8,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 # F1: 3,6 => CTR => F1: 4,5,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # A6: 1,5 => CTR => A6: 4,7,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 # A9: 1,5,9 => CTR => A9: 2,4
* PRF H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 # C1: 5,7 => SOL
* STA H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 + C1: 5,7
* CNT   8 HDP CHAINS /  25 HYP OPENED

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

Details

Positions

....2...18.4......3...........6.8.4..2....7.....3.....6..4...8..7..1.5........... initial
....2...18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7..1.5........... autosolve
765924831814763925392581476137658249528149763946372158651497382273816594489235617 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (3)
B6: 4,8
H5: 3,6
B9: 4,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,B3: 1.. / B2 = 1  =>  3 pairs (_) / B3 = 1  =>  3 pairs (_)
D5,F5: 1.. / D5 = 1  =>  3 pairs (_) / F5 = 1  =>  4 pairs (_)
C7,G7: 1.. / C7 = 1  =>  3 pairs (_) / G7 = 1  =>  3 pairs (_)
H6,H9: 1.. / H6 = 1  =>  3 pairs (_) / H9 = 1  =>  3 pairs (_)
G4,I4: 2.. / G4 = 2  =>  3 pairs (_) / I4 = 2  =>  3 pairs (_)
A8,A9: 2.. / A8 = 2  =>  4 pairs (_) / A9 = 2  =>  0 pairs (X)
D8,D9: 2.. / D8 = 2  =>  0 pairs (X) / D9 = 2  =>  4 pairs (_)
G7,I7: 2.. / G7 = 2  =>  3 pairs (_) / I7 = 2  =>  3 pairs (_)
A8,D8: 2.. / A8 = 2  =>  4 pairs (_) / D8 = 2  =>  0 pairs (X)
A9,D9: 2.. / A9 = 2  =>  0 pairs (X) / D9 = 2  =>  4 pairs (_)
G4,G7: 2.. / G4 = 2  =>  3 pairs (_) / G7 = 2  =>  3 pairs (_)
I4,I7: 2.. / I4 = 2  =>  3 pairs (_) / I7 = 2  =>  3 pairs (_)
B4,B7: 3.. / B4 = 3  =>  5 pairs (_) / B7 = 3  =>  8 pairs (_)
F1,G1: 4.. / F1 = 4  =>  4 pairs (_) / G1 = 4  =>  0 pairs (X)
A8,I8: 4.. / A8 = 4  =>  0 pairs (X) / I8 = 4  =>  4 pairs (_)
B6,B9: 4.. / B6 = 4  => 12 pairs (_) / B9 = 4  =>  5 pairs (_)
C5,C6: 6.. / C5 = 6  =>  0 pairs (X) / C6 = 6  =>  4 pairs (_)
A1,C1: 7.. / A1 = 7  =>  4 pairs (_) / C1 = 7  =>  4 pairs (_)
E4,E6: 7.. / E4 = 7  =>  3 pairs (_) / E6 = 7  =>  5 pairs (_)
F7,I7: 7.. / F7 = 7  =>  3 pairs (_) / I7 = 7  =>  3 pairs (_)
H3,H9: 7.. / H3 = 7  =>  3 pairs (_) / H9 = 7  =>  3 pairs (_)
D1,G1: 8.. / D1 = 8  =>  0 pairs (X) / G1 = 8  => 14 pairs (_)
C5,I5: 8.. / C5 = 8  => 12 pairs (_) / I5 = 8  =>  4 pairs (_)
C8,D8: 8.. / C8 = 8  =>  0 pairs (X) / D8 = 8  => 12 pairs (_)
B6,B9: 8.. / B6 = 8  =>  5 pairs (_) / B9 = 8  => 12 pairs (_)
E3,E9: 8.. / E3 = 8  => 15 pairs (_) / E9 = 8  =>  0 pairs (X)
* DURATION: 0:00:39.355567  START: 13:30:17.483770  END: 13:30:56.839337 2017-05-04
* CP COUNT: (26)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B6,B9,H5)
* ....2...18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7..1.5...........
* PAIR H5: 3,6 BLK 6
I5: 3,6,8                                # reduction candidate for 3,6
I5: 3,6                                  # 12 pairs
I5: 8                                    #  4 pairs
* PAIR H5: 3,6 ROW 5
C5: 3,6,8                                # reduction candidate for 3,6
C5: 8                                    # 12 pairs
C5: 3,6                                  #  4 pairs
* PAIR H5: 3,6 COL H
H1: 3,6,5,9                              # reduction candidate for 3,6
H1: 3,6                                  # 11 pairs
H8: 3,6,9                                # reduction candidate for 3,6
H8: 3,6 => CTR
* .6.8234.18.4....2.3.2...8.....6.8.4..2....7.8.8.3.2...6..43..8..78.1.534.43.8....
H8: 9                                    #  7 pairs
H9: 3,6,1,7,9                            # reduction candidate for 3,6
H9: 3,6 => CTR
* .6.82..518.4....2.3.2....7....6.8.4..2....7.....3.2.1.6..4...8..7821.59.24.......
H9: 1,7,9                                #  3 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-308-base-pr-000.dot
* REASONING
* DIS # H8: 3,6 => CTR => H8: 9
* DIS # H9: 3,6 => CTR => H9: 1,7,9
* CNT   2 HDP CHAINS /   9 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B6,B9,H5)
* ....2...18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7..1.5...........
* PAIR H5: 3,6 BLK 6
I5: 3,6,8                                # reduction candidate for 3,6
I5: 3,6                                  # 12 pairs
I5: 8                                    #  4 pairs
* PAIR H5: 3,6 ROW 5
C5: 3,6,8                                # reduction candidate for 3,6
C5: 8                                    # 12 pairs
C5: 3,6                                  #  4 pairs
* PAIR H5: 3,6 COL H
H1: 3,6,5,9                              # reduction candidate for 3,6
H1: 3,6                                  # 11 pairs
H8: 3,6,9                                # reduction candidate for 3,6
H8: 3,6 => CTR
* .6.8234.18.4....2.3.2...8.....6.8.4..2....7.8.8.3.2...6..43..8..78.1.534.43.8....
H9: 3,6,1,7                              # reduction candidate for 3,6
H9: 3,6 => CTR
* .6.82..518.4....2.3.2....7....6.8.4..2....7.....3.2.1.6..4...8..7821.59.24.......
* RESTART
* PAIR H5: 3,6 COL H
H1: 3,6,5                                # reduction candidate for 3,6
H1: 5 => CTR
* .6.82..518.4....2.3.2.........6.8.4..2....73....3.2...6..4...8..7821.59.24.......
* PAIR RESTART
* PAIR H5: 3,6 BLK 6
I5: 3,6,8                                # reduction candidate for 3,6
I5: 8                                    # 12 pairs
I5: 3,6                                  # 12 pairs
* PAIR H5: 3,6 ROW 5
C5: 3,6,8                                # reduction candidate for 3,6
C5: 8                                    # 12 pairs
C5: 3,6                                  # 12 pairs

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A8,B6,B9,C8,D8,F8,H1,H3,H5,H6,H9)
* ....2...18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7..1.59..........
* PAIR H1: 3,6 BLK 3
G1: 3,6,4,8,9                            # reduction candidate for 3,6
G1: 3,6 => CTR
* ...824..18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7821.59.24.......
G2: 3,6,9                                # reduction candidate for 3,6
G2: 3,6                                  # 12 pairs
I2: 3,6,5,7,9                            # reduction candidate for 3,6
I2: 3,6                                  # 16 pairs
* PAIR H1: 3,6 ROW 1
F1: 3,6,4,5,9                            # reduction candidate for 3,6
F1: 3,6 => CTR
* ...82.4.18.4....2.3.2.........6.8.4..2....7.....3.2...6..4...8..7821.59.24.......
* PAIR RESTART
* PAIR H3: 5,7 BLK 3
I2: 5,7,6,9                              # reduction candidate for 5,7
I2: 5,7                                  # 13 pairs
I3: 5,7,4,6,8,9                          # reduction candidate for 5,7
I3: 5,7                                  # 22 pairs
* PAIR H3: 5,7 ROW 3
D3: 5,7,1,8,9                            # reduction candidate for 5,7
D3: 5,7                                  # 15 pairs
F3: 5,7,1,4,6,9                          # reduction candidate for 5,7
F3: 5,7                                  # 15 pairs
* PAIR H6: 1,5 ROW 6
A6: 1,5,4,7,9                            # reduction candidate for 1,5
A6: 1,5 => CTR
* .6..2.8318.4.6392.3.2.8.4.6.3.6.8.49928.4.763.463721586..4...8..7381659448.2.....
* PAIR RESTART
* PAIR A8: 2,4 BLK 7
A9: 2,4,1,5,9                            # reduction candidate for 2,4
A9: 1,5,9 => CTR
* .6..2..318.4....2.3.2.........6.8.4..2....76...63.2...6..4...8.27.81.594.........

* LEVEL 0 PASS 1 ROUND 3 (AUTO SOLVE) (A1,A5,A6,B3,B7,C4,C9,D1,E4,E6,E7,F9)
* .6..248318147639253.2.8.47613.6.8249.28.4.763.463.21586.14.738227381659448.23.617
* PAIR A1: 5,7 BLK 1
C1: 5,7,9                                # reduction candidate for 5,7
C1: 5,7 => SOLVED
* 765924831814763925392581476137658249528149763946372158651497382273816594489235617
* DURATION: 0:00:28.735858  START: 13:31:05.294403  END: 13:31:34.030261 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-308-base-pr-001.dot
* REASONING
* DIS # H8: 3,6 => CTR => H8: 9
* DIS H8: 9 # H9: 3,6 => CTR => H9: 1,7
* DIS H8: 9 + H9: 1,7 # H1: 5 => CTR => H1: 3,6
* DIS H8: 9 + H9: 1,7 + H1: 3,6 # G1: 3,6 => CTR => G1: 4,8,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 # F1: 3,6 => CTR => F1: 4,5,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # A6: 1,5 => CTR => A6: 4,7,9
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 # A9: 1,5,9 => CTR => A9: 2,4
* PRF H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 # C1: 5,7 => SOL
* STA H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 + C1: 5,7
* CNT   8 HDP CHAINS /  25 HYP OPENED

Header Info

Top 500 Minimum 17 308

solution: 765924831814763925392581476137658249528149763946372158651497382273816594489235617
info: 2717     FNBHXYK  S8.f     40423

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

Solution

position: 765924831814763925392581476137658249528149763946372158651497382273816594489235617 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 # I5: 3,6 => UNS
* INC # I5: 8 => UNS
* INC # C5: 3,6 => UNS
* INC # C5: 8 => UNS
* INC # H1: 3,6 => UNS
* DIS # H8: 3,6 => CTR => H8: 9
* INC # H8: 9 => UNS
* DIS # H9: 3,6 => CTR => H9: 1,7,9
* INC # H9: 1,7,9 => UNS
* CNT   9 HDP CHAINS /   9 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # I5: 3,6 => UNS
* INC # I5: 8 => UNS
* INC # C5: 3,6 => UNS
* INC # C5: 8 => UNS
* INC # H1: 3,6 => UNS
* DIS # H8: 3,6 => CTR => H8: 9
* DIS H8: 9 # H9: 3,6 => CTR => H9: 1,7
* INC H8: 9 + H9: 1,7 # H1: 3,6 => UNS
* DIS H8: 9 + H9: 1,7 # H1: 5 => CTR => H1: 3,6
* INC H8: 9 + H9: 1,7 + H1: 3,6 # I5: 3,6 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 # I5: 8 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 # C5: 3,6 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 # C5: 8 => UNS
* DIS H8: 9 + H9: 1,7 + H1: 3,6 # G1: 3,6 => CTR => G1: 4,8,9
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 # G2: 3,6 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 # I2: 3,6 => UNS
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 # F1: 3,6 => CTR => F1: 4,5,9
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # I2: 5,7 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # I3: 5,7 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # D3: 5,7 => UNS
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # F3: 5,7 => UNS
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 # A6: 1,5 => CTR => A6: 4,7,9
* INC H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 # A9: 2,4 => UNS
* DIS H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 # A9: 1,5,9 => CTR => A9: 2,4
* PRF H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 # C1: 5,7 => SOL
* STA H8: 9 + H9: 1,7 + H1: 3,6 + G1: 4,8,9 + F1: 4,5,9 + A6: 4,7,9 + A9: 2,4 + C1: 5,7
* CNT  25 HDP CHAINS /  25 HYP OPENED