Analysis of xx-top500-216-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....6..8..2.........1.......7....1.25...3..........4....42.1...3..7..6.........5. initial

Autosolve

position: ....6..8..2.........1.......7....1.25...3..........4.5..42.1...3..7..6.........5. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I2: 1,7 => CTR => I2: 3,4,6,9
* DIS # E6: 2 => CTR => E6: 1,7
* DIS # F1: 2,7 => CTR => F1: 3,4,5,9
* DIS # F3: 2,7 => CTR => F3: 3,4,5,8,9
* DIS # G3: 2,7 => CTR => G3: 3,5,9
* DIS # E6: 2,7 => CTR => E6: 1
* DIS # I1: 1,4 => CTR => I1: 3,7,9
* DIS # I2: 1,4 => CTR => I2: 3,6,7,9
* DIS # D2: 1,4 => CTR => D2: 3,5,8,9
* DIS # H8: 1,4 => CTR => H8: 2
* DIS # F3: 2,4 => CTR => F3: 3,5,7,8,9
* DIS # H8: 1 => CTR => H8: 2,4
* DIS # E6: 7 => CTR => E6: 1,2
* DIS # I9: 7,9 => CTR => I9: 1,4,8
* CNT  14 HDP CHAINS /  35 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: 1,7 => CTR => I2: 3,4,6,9
* DIS I2: 3,4,6,9 # E6: 2 => CTR => E6: 1,7
* PRF I2: 3,4,6,9 + E6: 1,7 # D3: 3,9 => SOL
* STA I2: 3,4,6,9 + E6: 1,7 + D3: 3,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

....6..8..2.........1.......7....1.25...3..........4....42.1...3..7..6.........5. initial
....6..8..2.........1.......7....1.25...3..........4.5..42.1...3..7..6.........5. autosolve
947165283823974516651328947478596132516432879239817465764251398385749621192683754 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
E2: 1,7
E3: 2,7
H2: 1,4
H3: 2,4
A6: 1,2
A9: 1,2
D9: 3,6
F9: 3,6
H7: 7,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D1,I1: 1.. / D1 = 1  => 13 pairs (_) / I1 = 1  =>  0 pairs (X)
B5,D5: 1.. / B5 = 1  => 13 pairs (_) / D5 = 1  =>  0 pairs (X)
A6,A9: 1.. / A6 = 1  =>  0 pairs (X) / A9 = 1  => 13 pairs (_)
E2,E6: 1.. / E2 = 1  =>  0 pairs (X) / E6 = 1  => 13 pairs (_)
H2,H8: 1.. / H2 = 1  => 13 pairs (_) / H8 = 1  =>  0 pairs (X)
H8,G9: 2.. / H8 = 2  => 13 pairs (_) / G9 = 2  =>  0 pairs (X)
F1,G1: 2.. / F1 = 2  =>  0 pairs (X) / G1 = 2  => 13 pairs (_)
C5,F5: 2.. / C5 = 2  =>  0 pairs (X) / F5 = 2  => 13 pairs (_)
C8,H8: 2.. / C8 = 2  =>  0 pairs (X) / H8 = 2  => 13 pairs (_)
A6,A9: 2.. / A6 = 2  => 13 pairs (_) / A9 = 2  =>  0 pairs (X)
E3,E6: 2.. / E3 = 2  => 13 pairs (_) / E6 = 2  =>  0 pairs (X)
H3,H8: 2.. / H3 = 2  =>  0 pairs (X) / H8 = 2  => 13 pairs (_)
H4,H6: 3.. / H4 = 3  =>  9 pairs (_) / H6 = 3  => 10 pairs (_)
D9,F9: 3.. / D9 = 3  =>  7 pairs (_) / F9 = 3  =>  7 pairs (_)
G7,I7: 3.. / G7 = 3  =>  9 pairs (_) / I7 = 3  =>  9 pairs (_)
C4,H4: 3.. / C4 = 3  => 10 pairs (_) / H4 = 3  =>  9 pairs (_)
A4,B5: 4.. / A4 = 4  => 10 pairs (_) / B5 = 4  =>  0 pairs (X)
E9,I9: 4.. / E9 = 4  =>  9 pairs (_) / I9 = 4  => 11 pairs (_)
B7,E7: 5.. / B7 = 5  => 10 pairs (_) / E7 = 5  =>  9 pairs (_)
I2,I3: 6.. / I2 = 6  =>  9 pairs (_) / I3 = 6  =>  9 pairs (_)
A7,B7: 6.. / A7 = 6  =>  9 pairs (_) / B7 = 6  =>  9 pairs (_)
D9,F9: 6.. / D9 = 6  =>  7 pairs (_) / F9 = 6  =>  7 pairs (_)
A7,C9: 7.. / A7 = 7  => 19 pairs (_) / C9 = 7  =>  9 pairs (_)
G5,I5: 8.. / G5 = 8  => 10 pairs (_) / I5 = 8  => 10 pairs (_)
* DURATION: 0:00:39.411123  START: 10:11:41.628387  END: 10:12:21.039510 2017-05-04
* CP COUNT: (24)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,A9,D9,E2,E3,F9,H2,H3,H7)
* ....6..8..2.........1.......7....1.25...3..........4.5..42.1...3..7..6.........5.
* PAIR E2: 1,7 ROW 2
I2: 1,7,3,4,6,9                          # reduction candidate for 1,7
I2: 1,7 => CTR
* ....6..8..2.....4...1....26.7....1.25...3........2.4.5..42.1...3.27..61.1......5.
I2: 3,4,6,9                              #  9 pairs
* PAIR E2: 1,7 COL E
E6: 1,7,2                                # reduction candidate for 1,7
E6: 2 => CTR
* ....6..8..2..1..4...1.7..2..7....1.25...3........2.4.5..42.1...3.27..61.1......5.
E6: 1,7                                  # 13 pairs
* PAIR E3: 2,7 BLK 2
F1: 2,7,3,4,5,9                          # reduction candidate for 2,7
F1: 2,7 => CTR
* ....6..8..2..1..4...1....2..7....1.25...3........2.4.5..42.1...3.27..61.1......5.
F1: 3,4,5,9                              # 13 pairs
F3: 2,7,3,4,5,8,9                        # reduction candidate for 2,7
F3: 2,7 => CTR
* ....6.28..2..1..4...1.......7....1.25...3..........4.5..42.1...3..7..6.........5.
F3: 3,4,5,8,9                            #  9 pairs
* PAIR E3: 2,7 ROW 3
G3: 2,7,3,5,9                            # reduction candidate for 2,7
G3: 2,7 => CTR
* ...16..8..2..7..1...1.2.74..7....1.251..32...2...174.5764251.9.3..7..6211.2...85.
G3: 3,5,9                                #  9 pairs
* PAIR E3: 2,7 COL E
E6: 2,7,1                                # reduction candidate for 2,7
E6: 2,7 => CTR
* ....6..8..2..1..4...1....2..7....1.25...3........2.4.5..42.1...3.27..61.1......5.
E6: 1                                    # 13 pairs
* PAIR H2: 1,4 BLK 3
I1: 1,4,3,7,9                            # reduction candidate for 1,4
I1: 1,4 => CTR
* ....6..8..2.........1....2..7....1.25...3........2.4.5..42.1...3.27..6..1......5.
I1: 3,7,9                                # 13 pairs
I2: 1,4,3,6,7,9                          # reduction candidate for 1,4
I2: 1,4 => CTR
* ...16..8..2..7......1.2...6.7....1.25...3..........4.5..42.1...3..7..6.........5.
I2: 3,6,7,9                              #  9 pairs
* PAIR H2: 1,4 ROW 2
D2: 1,4,3,5,8,9                          # reduction candidate for 1,4
D2: 1,4 => CTR
* ..7.6.28..2.47..1...1.2..4..7....1.251..3........1.4.5..42.1...3..7..62.1.2....5.
D2: 3,5,8,9                              #  9 pairs
* PAIR H2: 1,4 COL H
H8: 1,4,2                                # reduction candidate for 1,4
H8: 1,4 => CTR
* ....6..8..2.........1....2..7....1.25...3........2.4.5..42.1...3.27..6..1......5.
H8: 2                                    # 13 pairs
* PAIR H3: 2,4 ROW 3
F3: 2,4,3,5,7,8,9                        # reduction candidate for 2,4
F3: 2,4 => CTR
* ....6.28..2..1..4...1.7.....7....1.25...3........2.4.5..42.1...3..7..6..2......5.
F3: 3,5,7,8,9                            #  9 pairs
* PAIR H3: 2,4 COL H
H8: 2,4,1                                # reduction candidate for 2,4
H8: 1 => CTR
* ....6..8..2.........1....2..7....1.25...3........2.4.5..42.1...3.27..61.1......5.
H8: 2,4                                  # 13 pairs
* PAIR A6: 1,2 ROW 6
E6: 1,2,7                                # reduction candidate for 1,2
E6: 7 => CTR
* ....6..8..2..1..4...1.2.....7....1.25...3..........4.5..42.1...3..7..6.........5.
E6: 1,2                                  # 10 pairs
* PAIR H7: 7,9 BLK 9
G7: 7,9,3,8                              # reduction candidate for 7,9
G7: 7,9                                  # 13 pairs
I7: 7,9,3,8                              # reduction candidate for 7,9
I7: 7,9                                  # 13 pairs
G9: 7,9,2,8                              # reduction candidate for 7,9
G9: 7,9                                  # 13 pairs
I9: 7,9,1,4,8                            # reduction candidate for 7,9
I9: 7,9 => CTR
* ....6..8..2.........1....2..7....1.25...3........2.4.5..42.1...3.27..6..1...4..5.
I9: 1,4,8                                #  9 pairs
* PAIR H7: 7,9 ROW 7
A7: 7,9,6,8                              # reduction candidate for 7,9
A7: 7,9                                  # 12 pairs
A7: 6,8                                  # 10 pairs
* PAIR H7: 7,9 COL H
H5: 7,9,6                                # reduction candidate for 7,9
H5: 7,9                                  # 13 pairs
H6: 7,9,3,6                              # reduction candidate for 7,9
H6: 7,9                                  # 11 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-216-base-pr-000.dot
* REASONING
* DIS # I2: 1,7 => CTR => I2: 3,4,6,9
* DIS # E6: 2 => CTR => E6: 1,7
* DIS # F1: 2,7 => CTR => F1: 3,4,5,9
* DIS # F3: 2,7 => CTR => F3: 3,4,5,8,9
* DIS # G3: 2,7 => CTR => G3: 3,5,9
* DIS # E6: 2,7 => CTR => E6: 1
* DIS # I1: 1,4 => CTR => I1: 3,7,9
* DIS # I2: 1,4 => CTR => I2: 3,6,7,9
* DIS # D2: 1,4 => CTR => D2: 3,5,8,9
* DIS # H8: 1,4 => CTR => H8: 2
* DIS # F3: 2,4 => CTR => F3: 3,5,7,8,9
* DIS # H8: 1 => CTR => H8: 2,4
* DIS # E6: 7 => CTR => E6: 1,2
* DIS # I9: 7,9 => CTR => I9: 1,4,8
* CNT  14 HDP CHAINS /  35 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A6,A9,D9,E2,E3,F9,H2,H3,H7)
* ....6..8..2.........1.......7....1.25...3..........4.5..42.1...3..7..6.........5.
* PAIR E2: 1,7 ROW 2
I2: 1,7,3,4,6,9                          # reduction candidate for 1,7
I2: 1,7 => CTR
* ....6..8..2.....4...1....26.7....1.25...3........2.4.5..42.1...3.27..61.1......5.
* PAIR E2: 1,7 COL E
E6: 1,7,2                                # reduction candidate for 1,7
E6: 2 => CTR
* ....6..8..2..1..4...1.7..2..7....1.25...3........2.4.5..42.1...3.27..61.1......5.
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (B3,B9,C2,D2,D9,E4,E9,F8,F9,G2,G3,H4,H6)
* 94716528382..74.166.1.2..4747.5..1.25164328792...174.57642513983..74.6211.2...754
* PAIR D2: 3,9 BLK 2
D3: 3,9,8                                # reduction candidate for 3,9
D3: 3,9 => SOLVED
* 947165283823974516651328947478596132516432879239817465764251398385749621192683754
* DURATION: 0:00:07.124058  START: 10:12:51.657089  END: 10:12:58.781147 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-216-base-pr-001.dot
* REASONING
* DIS # I2: 1,7 => CTR => I2: 3,4,6,9
* DIS I2: 3,4,6,9 # E6: 2 => CTR => E6: 1,7
* PRF I2: 3,4,6,9 + E6: 1,7 # D3: 3,9 => SOL
* STA I2: 3,4,6,9 + E6: 1,7 + D3: 3,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 216

solution: 947165283823974516651328947478596132516432879239817465764251398385749621192683754
info: 1949     FNBHXY   S8.f     5212

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

Solution

position: 947165283823974516651328947478596132516432879239817465764251398385749621192683754 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: 1,7 => CTR => I2: 3,4,6,9
* INC # I2: 3,4,6,9 => UNS
* INC # E6: 1,7 => UNS
* DIS # E6: 2 => CTR => E6: 1,7
* DIS # F1: 2,7 => CTR => F1: 3,4,5,9
* INC # F1: 3,4,5,9 => UNS
* DIS # F3: 2,7 => CTR => F3: 3,4,5,8,9
* INC # F3: 3,4,5,8,9 => UNS
* DIS # G3: 2,7 => CTR => G3: 3,5,9
* INC # G3: 3,5,9 => UNS
* DIS # E6: 2,7 => CTR => E6: 1
* INC # E6: 1 => UNS
* DIS # I1: 1,4 => CTR => I1: 3,7,9
* INC # I1: 3,7,9 => UNS
* DIS # I2: 1,4 => CTR => I2: 3,6,7,9
* INC # I2: 3,6,7,9 => UNS
* DIS # D2: 1,4 => CTR => D2: 3,5,8,9
* INC # D2: 3,5,8,9 => UNS
* DIS # H8: 1,4 => CTR => H8: 2
* INC # H8: 2 => UNS
* DIS # F3: 2,4 => CTR => F3: 3,5,7,8,9
* INC # F3: 3,5,7,8,9 => UNS
* INC # H8: 2,4 => UNS
* DIS # H8: 1 => CTR => H8: 2,4
* INC # E6: 1,2 => UNS
* DIS # E6: 7 => CTR => E6: 1,2
* INC # G7: 7,9 => UNS
* INC # I7: 7,9 => UNS
* INC # G9: 7,9 => UNS
* DIS # I9: 7,9 => CTR => I9: 1,4,8
* INC # I9: 1,4,8 => UNS
* INC # A7: 7,9 => UNS
* INC # A7: 6,8 => UNS
* INC # H5: 7,9 => UNS
* INC # H6: 7,9 => UNS
* CNT  35 HDP CHAINS /  35 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # I2: 1,7 => CTR => I2: 3,4,6,9
* INC I2: 3,4,6,9 # E6: 1,7 => UNS
* DIS I2: 3,4,6,9 # E6: 2 => CTR => E6: 1,7
* PRF I2: 3,4,6,9 + E6: 1,7 # D3: 3,9 => SOL
* STA I2: 3,4,6,9 + E6: 1,7 + D3: 3,9
* CNT   4 HDP CHAINS /   4 HYP OPENED