Analysis of xx-top500-217-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .5.....8......3......4.....3.42.........7..9.6.............64.3....1.2...7.5..... initial

Autosolve

position: .5.....8......3......4.....3.42.........7..9.6.7...........64.3....1.2...7.5..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I2: 4,6 => CTR => I2: 1,2,5,7,9
* DIS # B8: 3 => CTR => B8: 4,6
* DIS # C1: 3,6 => CTR => C1: 1,2,9
* DIS # C3: 3,6 => CTR => C3: 1,2,8,9
* DIS # G3: 3,6 => CTR => G3: 1,5,7,9
* DIS # B8: 3,6 => CTR => B8: 4
* DIS # I1: 2,4 => CTR => I1: 1,6,7,9
* DIS # I2: 2,4 => CTR => I2: 1,5,6,7,9
* DIS # A2: 2,4 => CTR => A2: 1,7,8,9
* DIS # H6: 2,4 => CTR => H6: 3
* DIS # C3: 2,3 => CTR => C3: 1,6,8,9
* DIS # H6: 4 => CTR => H6: 2,3
* DIS # H6: 2 => CTR => H6: 3,4
* CNT  13 HDP CHAINS /  32 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 # I2: 4,6 => CTR => I2: 1,2,5,7,9
* DIS I2: 1,2,5,7,9 # B8: 3 => CTR => B8: 4,6
* PRF I2: 1,2,5,7,9 + B8: 4,6 # A2: 8,9 => SOL
* STA I2: 1,2,5,7,9 + B8: 4,6 + A2: 8,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.5.....8......3......4.....3.42.........7..9.6.............64.3....1.2...7.5..... initial
.5.....8......3......4.....3.42.........7..9.6.7...........64.3....1.2...7.5..... autosolve
451692387862753149739481526384269751125378694697145832518926473943817265276534918 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
B2: 4,6
B3: 3,6
H2: 2,4
H3: 2,3
E6: 3,4
E9: 3,4
H9: 1,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E7,F9: 2.. / E7 = 2  =>  9 pairs (_) / F9 = 2  =>  8 pairs (_)
D8,E9: 3.. / D8 = 3  =>  0 pairs (X) / E9 = 3  => 17 pairs (_)
C1,G1: 3.. / C1 = 3  =>  0 pairs (X) / G1 = 3  => 17 pairs (_)
D5,G5: 3.. / D5 = 3  => 17 pairs (_) / G5 = 3  =>  0 pairs (X)
C9,E9: 3.. / C9 = 3  =>  0 pairs (X) / E9 = 3  => 17 pairs (_)
B3,B8: 3.. / B3 = 3  => 17 pairs (_) / B8 = 3  =>  0 pairs (X)
E6,E9: 3.. / E6 = 3  =>  0 pairs (X) / E9 = 3  => 17 pairs (_)
H3,H6: 3.. / H3 = 3  =>  0 pairs (X) / H6 = 3  => 17 pairs (_)
A1,I1: 4.. / A1 = 4  => 17 pairs (_) / I1 = 4  =>  0 pairs (X)
F5,I5: 4.. / F5 = 4  =>  0 pairs (X) / I5 = 4  => 17 pairs (_)
B2,B8: 4.. / B2 = 4  =>  0 pairs (X) / B8 = 4  => 17 pairs (_)
E6,E9: 4.. / E6 = 4  => 17 pairs (_) / E9 = 4  =>  0 pairs (X)
H2,H6: 4.. / H2 = 4  => 17 pairs (_) / H6 = 4  =>  0 pairs (X)
A5,C5: 5.. / A5 = 5  =>  7 pairs (_) / C5 = 5  =>  7 pairs (_)
E4,D5: 6.. / E4 = 6  =>  8 pairs (_) / D5 = 6  =>  0 pairs (X)
D7,H7: 7.. / D7 = 7  =>  8 pairs (_) / H7 = 7  =>  9 pairs (_)
B4,B6: 9.. / B4 = 9  =>  7 pairs (_) / B6 = 9  =>  8 pairs (_)
* DURATION: 0:00:25.358043  START: 10:13:14.221572  END: 10:13:39.579615 2017-05-04
* CP COUNT: (17)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B3,E6,E9,H2,H3,H9)
* .5.....8......3......4.....3.42.........7..9.6.7...........64.3....1.2...7.5.....
* PAIR B2: 4,6 ROW 2
I2: 4,6,1,2,5,7,9                        # reduction candidate for 4,6
I2: 4,6 => CTR
* .5.....8......3.2....4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
I2: 1,2,5,7,9                            #  7 pairs
* PAIR B2: 4,6 COL B
B8: 4,6,3                                # reduction candidate for 4,6
B8: 3 => CTR
* .5.....8..4...3.2..6.4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
B8: 4,6                                  # 17 pairs
* PAIR B3: 3,6 BLK 1
C1: 3,6,1,2,9                            # reduction candidate for 3,6
C1: 3,6 => CTR
* .5.....8..4...3.2....4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
C1: 1,2,9                                # 17 pairs
C3: 3,6,1,2,8,9                          # reduction candidate for 3,6
C3: 3,6 => CTR
* .5....38..4...3.2....4.....3.42.........7..9.6.7...........64.3....1.2...7.5.....
C3: 1,2,8,9                              #  7 pairs
* PAIR B3: 3,6 ROW 3
G3: 3,6,1,5,7,9                          # reduction candidate for 3,6
G3: 3,6 => CTR
* 45...238..6...3.4..3.4..62.3.426.......37..9.6.7.4..3......64.3.43.1.2...76534.1.
G3: 1,5,7,9                              #  7 pairs
* PAIR B3: 3,6 COL B
B8: 3,6,4                                # reduction candidate for 3,6
B8: 3,6 => CTR
* .5.....8..4...3.2....4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
B8: 4                                    # 17 pairs
* PAIR H2: 2,4 BLK 3
I1: 2,4,1,6,7,9                          # reduction candidate for 2,4
I1: 2,4 => CTR
* .53....8..4...3.2..6.4...3.3.42.........7..9.6.7.4.........64.3.3..1.2...7.53....
I1: 1,6,7,9                              # 17 pairs
I2: 2,4,1,5,6,7,9                        # reduction candidate for 2,4
I2: 2,4 => CTR
* 45.....8..6...3....3.4.....3.42.........7..9.6.7...........64.3....1.2...7.5.....
I2: 1,5,6,7,9                            #  7 pairs
* PAIR H2: 2,4 ROW 2
A2: 2,4,1,7,8,9                          # reduction candidate for 2,4
A2: 2,4 => CTR
* .5...238.26...3.4..3.4...2.3.42........37..946.7.4..32....264.3.43.1.2...7.534...
A2: 1,7,8,9                              #  7 pairs
* PAIR H2: 2,4 COL H
H6: 2,4,3                                # reduction candidate for 2,4
H6: 2,4 => CTR
* .53....8..4...3.2..6.4...3.3.42.........7..9.6.7.4.........64.3.3..1.2...7.53....
H6: 3                                    # 17 pairs
* PAIR H3: 2,3 ROW 3
C3: 2,3,1,6,8,9                          # reduction candidate for 2,3
C3: 2,3 => CTR
* .5.....8..4...3.2..624...3.3.42.........7..9.6.7.4.........64.3.3..1.2...7.53....
C3: 1,6,8,9                              #  7 pairs
* PAIR H3: 2,3 COL H
H6: 2,3,4                                # reduction candidate for 2,3
H6: 4 => CTR
* .5.....8......3......4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
H6: 2,3                                  # 17 pairs
* PAIR E6: 3,4 ROW 6
H6: 3,4,2                                # reduction candidate for 3,4
H6: 2 => CTR
* .5.....8......3.4....4...3.3.42.........7..9.6.7....2......64.3....1.2...7.5.....
H6: 3,4                                  #  8 pairs
* PAIR H9: 1,6 BLK 9
G9: 1,6,8,9                              # reduction candidate for 1,6
G9: 1,6                                  # 13 pairs
I9: 1,6,8,9                              # reduction candidate for 1,6
I9: 1,6                                  # 13 pairs
* PAIR H9: 1,6 ROW 9
C9: 1,6,2,3,8,9                          # reduction candidate for 1,6
C9: 1,6                                  # 17 pairs
C9: 2,3,8,9                              #  8 pairs
* PAIR H9: 1,6 COL H
H4: 1,6,5,7                              # reduction candidate for 1,6
H4: 5,7                                  # 12 pairs
H4: 1,6                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-217-base-pr-000.dot
* REASONING
* DIS # I2: 4,6 => CTR => I2: 1,2,5,7,9
* DIS # B8: 3 => CTR => B8: 4,6
* DIS # C1: 3,6 => CTR => C1: 1,2,9
* DIS # C3: 3,6 => CTR => C3: 1,2,8,9
* DIS # G3: 3,6 => CTR => G3: 1,5,7,9
* DIS # B8: 3,6 => CTR => B8: 4
* DIS # I1: 2,4 => CTR => I1: 1,6,7,9
* DIS # I2: 2,4 => CTR => I2: 1,5,6,7,9
* DIS # A2: 2,4 => CTR => A2: 1,7,8,9
* DIS # H6: 2,4 => CTR => H6: 3
* DIS # C3: 2,3 => CTR => C3: 1,6,8,9
* DIS # H6: 4 => CTR => H6: 2,3
* DIS # H6: 2 => CTR => H6: 3,4
* CNT  13 HDP CHAINS /  32 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B3,E6,E9,H2,H3,H9)
* .5.....8......3......4.....3.42.........7..9.6.7...........64.3....1.2...7.5.....
* PAIR B2: 4,6 ROW 2
I2: 4,6,1,2,5,7,9                        # reduction candidate for 4,6
I2: 4,6 => CTR
* .5.....8......3.2....4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
* PAIR B2: 4,6 COL B
B8: 4,6,3                                # reduction candidate for 4,6
B8: 3 => CTR
* .5.....8..4...3.2..6.4...3.3.42.........7..9.6.7....4......64.3.3..1.2...7.5.....
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A5,A7,A8,B7,C3,C5,D2,D7,E2,E3,F3,F5,G6,G9,I2,I4,I9)
* 451692387.62..3.4..3.4...263.426.75..2.37.6946.7.45.32....26473.43.1.265276534.1.
* PAIR C3: 8,9 BLK 1
A2: 8,9,7                                # reduction candidate for 8,9
A2: 8,9 => SOLVED
* 451692387862753149739481526384269751125378694697145832518926473943817265276534918
* DURATION: 0:00:06.235572  START: 10:14:03.862070  END: 10:14:10.097642 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-217-base-pr-001.dot
* REASONING
* DIS # I2: 4,6 => CTR => I2: 1,2,5,7,9
* DIS I2: 1,2,5,7,9 # B8: 3 => CTR => B8: 4,6
* PRF I2: 1,2,5,7,9 + B8: 4,6 # A2: 8,9 => SOL
* STA I2: 1,2,5,7,9 + B8: 4,6 + A2: 8,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 217

solution: 451692387862753149739481526384269751125378694697145832518926473943817265276534918
info: 1949     FNBHXY   S8.f     19701

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

Solution

position: 451692387862753149739481526384269751125378694697145832518926473943817265276534918 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:

* DIS # I2: 4,6 => CTR => I2: 1,2,5,7,9
* INC # I2: 1,2,5,7,9 => UNS
* INC # B8: 4,6 => UNS
* DIS # B8: 3 => CTR => B8: 4,6
* DIS # C1: 3,6 => CTR => C1: 1,2,9
* INC # C1: 1,2,9 => UNS
* DIS # C3: 3,6 => CTR => C3: 1,2,8,9
* INC # C3: 1,2,8,9 => UNS
* DIS # G3: 3,6 => CTR => G3: 1,5,7,9
* INC # G3: 1,5,7,9 => UNS
* DIS # B8: 3,6 => CTR => B8: 4
* INC # B8: 4 => UNS
* DIS # I1: 2,4 => CTR => I1: 1,6,7,9
* INC # I1: 1,6,7,9 => UNS
* DIS # I2: 2,4 => CTR => I2: 1,5,6,7,9
* INC # I2: 1,5,6,7,9 => UNS
* DIS # A2: 2,4 => CTR => A2: 1,7,8,9
* INC # A2: 1,7,8,9 => UNS
* DIS # H6: 2,4 => CTR => H6: 3
* INC # H6: 3 => UNS
* DIS # C3: 2,3 => CTR => C3: 1,6,8,9
* INC # C3: 1,6,8,9 => UNS
* INC # H6: 2,3 => UNS
* DIS # H6: 4 => CTR => H6: 2,3
* INC # H6: 3,4 => UNS
* DIS # H6: 2 => CTR => H6: 3,4
* INC # G9: 1,6 => UNS
* INC # I9: 1,6 => UNS
* INC # C9: 1,6 => UNS
* INC # C9: 2,3,8,9 => UNS
* INC # H4: 1,6 => UNS
* INC # H4: 5,7 => UNS
* CNT  32 HDP CHAINS /  32 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # I2: 4,6 => CTR => I2: 1,2,5,7,9
* INC I2: 1,2,5,7,9 # B8: 4,6 => UNS
* DIS I2: 1,2,5,7,9 # B8: 3 => CTR => B8: 4,6
* PRF I2: 1,2,5,7,9 + B8: 4,6 # A2: 8,9 => SOL
* STA I2: 1,2,5,7,9 + B8: 4,6 + A2: 8,9
* CNT   4 HDP CHAINS /   4 HYP OPENED