Analysis of xx-top500-468-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 67.3.....4......8........19..1...7.....6..2..5...8.....9..1.......5..4........... initial

Autosolve

position: 6783915..4192..387......619..1...7.8...6..2.15..18.9...9..1.8..1..5..4........1.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A4: 2,3 => CTR => A4: 9
* PRF # A4: 9 => SOL
* PRF # A7: 2,3 => SOL
* DIS # A7: 7 => CTR => A7: 2,3
* DIS # A9: 2,3 => CTR => A9: 7,8
* DIS # D3: 4,7 => CTR => D3: 8
* DIS # F4: 4,9 => CTR => F4: 2,3,5
* PRF # D9: 4,9 => SOL
* DIS # D9: 7,8 => CTR => D9: 4,9
* DIS # F7: 4,7 => CTR => F7: 2,3,6
* DIS # D9: 4,7 => CTR => D9: 8,9
* PRF # C7: 4,7 => SOL
* DIS # D3: 4,7 => CTR => D3: 8
* CNT  13 HDP CHAINS /  28 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 # A4: 2,3 => CTR => A4: 9
* PRF A4: 9 => SOL
* STA A4: 9
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

67.3.....4......8........19..1...7.....6..2..5...8.....9..1.......5..4........... initial
6783915..4192..387......619..1...7.8...6..2.15..18.9...9..1.8..1..5..4........1.. autosolve
678391524419265387325874619961432758783659241542187963294716835137528496856943172 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
A3: 2,3
E2: 5,6
F2: 5,6
E3: 4,7
H1: 2,4
I1: 2,4
D4: 4,9
D7: 4,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H1,I1: 2.. / H1 = 2  =>  7 pairs (_) / I1 = 2  => 10 pairs (_)
H1,I1: 4.. / H1 = 4  => 10 pairs (_) / I1 = 4  =>  7 pairs (_)
I1,I6: 4.. / I1 = 4  =>  7 pairs (_) / I6 = 4  => 10 pairs (_)
B3,C3: 5.. / B3 = 5  =>  9 pairs (_) / C3 = 5  => 10 pairs (_)
E2,F2: 5.. / E2 = 5  =>  6 pairs (_) / F2 = 5  =>  6 pairs (_)
H4,H5: 5.. / H4 = 5  =>  9 pairs (_) / H5 = 5  =>  8 pairs (_)
I7,I9: 5.. / I7 = 5  =>  8 pairs (_) / I9 = 5  =>  9 pairs (_)
C7,I7: 5.. / C7 = 5  =>  9 pairs (_) / I7 = 5  =>  8 pairs (_)
B3,B9: 5.. / B3 = 5  =>  9 pairs (_) / B9 = 5  => 10 pairs (_)
E2,F2: 6.. / E2 = 6  =>  6 pairs (_) / F2 = 6  =>  6 pairs (_)
B4,H4: 6.. / B4 = 6  =>  8 pairs (_) / H4 = 6  => 12 pairs (_)
C6,F6: 7.. / C6 = 7  =>  9 pairs (_) / F6 = 7  => 10 pairs (_)
D3,F3: 8.. / D3 = 8  =>  9 pairs (_) / F3 = 8  =>  0 pairs (X)
A5,B5: 8.. / A5 = 8  =>  0 pairs (X) / B5 = 8  =>  0 pairs (_)
B8,F8: 8.. / B8 = 8  =>  0 pairs (X) / F8 = 8  =>  0 pairs (_)
A5,A9: 8.. / A5 = 8  =>  0 pairs (X) / A9 = 8  =>  0 pairs (_)
D3,D9: 8.. / D3 = 8  =>  9 pairs (_) / D9 = 8  =>  0 pairs (X)
A4,A5: 9.. / A4 = 9  =>  0 pairs (*) / A5 = 9  =>  0 pairs (X)
H8,H9: 9.. / H8 = 9  =>  8 pairs (_) / H9 = 9  =>  0 pairs (X)
A5,F5: 9.. / A5 = 9  =>  0 pairs (X) / F5 = 9  =>  0 pairs (_)
F8,H8: 9.. / F8 = 9  =>  0 pairs (X) / H8 = 9  =>  8 pairs (_)
D4,D9: 9.. / D4 = 9  =>  0 pairs (X) / D9 = 9  =>  0 pairs (_)
* DURATION: 0:00:30.163992  START: 18:42:02.959779  END: 18:42:33.123771 2017-05-04
* CP COUNT: (22)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,D4,D7,E2,E3,F2,H1,I1)
* 6783915..4192..387......619..1...7.8...6..2.15..18.9...9..1.8..1..5..4........1..
* PAIR A3: 2,3 BLK 1
B3: 2,3,5                                # reduction candidate for 2,3
B3: 2,3                                  # 10 pairs
C3: 2,3,5                                # reduction candidate for 2,3
C3: 2,3                                  #  9 pairs
* PAIR A3: 2,3 COL A
A4: 2,3,9                                # reduction candidate for 2,3
A4: 2,3 => CTR
* 6783915..4192..387...8..619..1...7.898.6..2.15..18.9..79.41.8..1..57849.8..9..1..
A4: 9 => SOLVED
* 678391524419265387325874619961432758783659241542187963294716835137528496856943172
A7: 2,3,7                                # reduction candidate for 2,3
A7: 2,3 => SOLVED
* 678391524419265387325874619961432758783659241542187963294716835137528496856943172
A7: 7 => CTR
* 6783915..4192..387......619..19..7.898.6..2.15..18.9..79.41.8..1..5.849.8..7.91..
A9: 2,3,7,8                              # reduction candidate for 2,3
A9: 2,3 => CTR
* 6783915..4192..387......619..1...7.88..6.92.15..18.9..79.41.8..1..5..4........1..
A9: 7,8                                  #  9 pairs
* PAIR E3: 4,7 BLK 2
D3: 4,7,8                                # reduction candidate for 4,7
D3: 4,7 => CTR
* 6783915..4192..387.....8619..19..7.8...6..2.15..18.9...9..1.8..18.5..4.....8..1..
D3: 8                                    #  9 pairs
F3: 4,7,8                                # reduction candidate for 4,7
F3: 4,7                                  #  9 pairs
* PAIR E3: 4,7 COL E
E5: 4,7,3,5                              # reduction candidate for 4,7
E5: 4,7                                  #  9 pairs
E9: 4,7,2,3,6                            # reduction candidate for 4,7
E9: 4,7                                  # 12 pairs
* PAIR D4: 4,9 BLK 5
F4: 4,9,2,3,5                            # reduction candidate for 4,9
F4: 4,9 => CTR
* 6783915..4192..387......619..1...7.898.6..2.15..18.9..79.41.8..1..5.849.8.....17.
F4: 2,3,5                                #  8 pairs
F5: 4,9,3,5,7                            # reduction candidate for 4,9
F5: 4,9                                  #  9 pairs
* PAIR D4: 4,9 COL D
D9: 4,9,7,8                              # reduction candidate for 4,9
D9: 4,9 => SOLVED
* 678391524419265387325874619961432758783659241542187963294716835137528496856943172
D9: 7,8 => CTR
* 6783915..4192..387...8..619..19..7.898.6..2.15..18.9..79.41.8..1..5.849.8..7.91..
* PAIR D7: 4,7 BLK 8
F7: 4,7,2,3,6                            # reduction candidate for 4,7
F7: 4,7 => CTR
* 6783915..4192..387...8476199.14..7.878.6.92.15..18.9...9.7148..1.75.849.8..9..17.
F7: 2,3,6                                #  8 pairs
D9: 4,7,8,9                              # reduction candidate for 4,7
D9: 4,7 => CTR
* 6783915..4192..387...8..619..19..7.898.6..2.15..18.9..79.41.8..1..57849.8....91..
D9: 8,9                                  #  9 pairs
E9: 4,7,2,3,6                            # reduction candidate for 4,7
E9: 4,7                                  # 12 pairs
F9: 4,7,2,3,6,8,9                        # reduction candidate for 4,7
F9: 4,7                                  # 11 pairs
* PAIR D7: 4,7 ROW 7
C7: 4,7,2,3,5,6                          # reduction candidate for 4,7
C7: 4,7 => SOLVED
* 678391524419265387325874619961432758783659241542187963294716835137528496856943172
C7: 2,3,5,6                              #  8 pairs
* PAIR D7: 4,7 COL D
D3: 4,7,8                                # reduction candidate for 4,7
D3: 4,7 => CTR
* 6783915..4192..387.....8619..19..7.8...6..2.15..18.9...9..1.8..18.5..4.....8..1..
D3: 8                                    #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-468-base-pr-000.dot
* REASONING
* DIS # A4: 2,3 => CTR => A4: 9
* PRF # A4: 9 => SOL
* PRF # A7: 2,3 => SOL
* DIS # A7: 7 => CTR => A7: 2,3
* DIS # A9: 2,3 => CTR => A9: 7,8
* DIS # D3: 4,7 => CTR => D3: 8
* DIS # F4: 4,9 => CTR => F4: 2,3,5
* PRF # D9: 4,9 => SOL
* DIS # D9: 7,8 => CTR => D9: 4,9
* DIS # F7: 4,7 => CTR => F7: 2,3,6
* DIS # D9: 4,7 => CTR => D9: 8,9
* PRF # C7: 4,7 => SOL
* DIS # D3: 4,7 => CTR => D3: 8
* CNT  13 HDP CHAINS /  28 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,D4,D7,E2,E3,F2,H1,I1)
* 6783915..4192..387......619..1...7.8...6..2.15..18.9...9..1.8..1..5..4........1..
* PAIR A3: 2,3 BLK 1
B3: 2,3,5                                # reduction candidate for 2,3
B3: 2,3                                  # 10 pairs
C3: 2,3,5                                # reduction candidate for 2,3
C3: 2,3                                  #  9 pairs
* PAIR A3: 2,3 COL A
A4: 2,3,9                                # reduction candidate for 2,3
A4: 2,3 => CTR
* 6783915..4192..387...8..619..1...7.898.6..2.15..18.9..79.41.8..1..57849.8..9..1..
A4: 9 => SOLVED
* 678391524419265387325874619961432758783659241542187963294716835137528496856943172
* DURATION: 0:00:02.938172  START: 18:42:55.019868  END: 18:42:57.958040 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-468-base-pr-001.dot
* REASONING
* DIS # A4: 2,3 => CTR => A4: 9
* PRF A4: 9 => SOL
* STA A4: 9
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 468

solution: 678391524419265387325874619961432758783659241542187963294716835137528496856943172
info: 95591    FNBHYK   S8.f     43904

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

Solution

position: 678391524419265387325874619961432758783659241542187963294716835137528496856943172 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 # B3: 2,3 => UNS
* INC # C3: 2,3 => UNS
* DIS # A4: 2,3 => CTR => A4: 9
* PRF # A4: 9 => SOL
* PRF # A7: 2,3 => SOL
* DIS # A7: 7 => CTR => A7: 2,3
* DIS # A9: 2,3 => CTR => A9: 7,8
* INC # A9: 7,8 => UNS
* DIS # D3: 4,7 => CTR => D3: 8
* INC # D3: 8 => UNS
* INC # F3: 4,7 => UNS
* INC # E5: 4,7 => UNS
* INC # E9: 4,7 => UNS
* DIS # F4: 4,9 => CTR => F4: 2,3,5
* INC # F4: 2,3,5 => UNS
* INC # F5: 4,9 => UNS
* PRF # D9: 4,9 => SOL
* DIS # D9: 7,8 => CTR => D9: 4,9
* DIS # F7: 4,7 => CTR => F7: 2,3,6
* INC # F7: 2,3,6 => UNS
* DIS # D9: 4,7 => CTR => D9: 8,9
* INC # D9: 8,9 => UNS
* INC # E9: 4,7 => UNS
* INC # F9: 4,7 => UNS
* PRF # C7: 4,7 => SOL
* INC # C7: 2,3,5,6 => UNS
* DIS # D3: 4,7 => CTR => D3: 8
* INC # D3: 8 => UNS
* CNT  28 HDP CHAINS /  28 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 2,3 => UNS
* INC # C3: 2,3 => UNS
* DIS # A4: 2,3 => CTR => A4: 9
* PRF A4: 9 => SOL
* STA A4: 9
* CNT   4 HDP CHAINS /   3 HYP OPENED