Analysis of xx-top500-453-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .8.69....5......1...........3.7..8.....2.....1........4...15.........3.8....4.6.. initial

Autosolve

position: .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C3: 3,6 => CTR => C3: 2,7,9
* DIS # F3: 2,7 => CTR => F3: 3
* PRF # A3: 2,9 => SOL
* DIS # A9: 2,9 => CTR => A9: 3,7,8
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* DIS # A3: 2,7 => CTR => A3: 3,6,9
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* DIS # F3: 2,7 => CTR => F3: 3
* CNT  10 HDP CHAINS /  42 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 # C3: 3,6 => CTR => C3: 2,7,9
* DIS C3: 2,7,9 # F3: 2,7 => CTR => F3: 3
* PRF C3: 2,7,9 + F3: 3 # A3: 2,9 => SOL
* STA C3: 2,7,9 + F3: 3 + A3: 2,9
* CNT   3 HDP CHAINS /   9 HYP OPENED

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

Details

Positions

.8.69....5......1...........3.7..8.....2.....1........4...15.........3.8....4.6.. initial
.8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651 autosolve
381692574526478913947153286234761895659284137178539462463815729715926348892347651 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
C2: 3,6
E2: 2,7
I2: 3,6
A4: 2,9
B6: 2,7
E5: 3,8
E6: 3,8
H4: 2,9
C7: 3,8
A8: 2,7
D7: 3,8
E8: 2,7
D9: 3,8
F9: 2,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E8,F9: 2.. / E8 = 2  =>  0 pairs (*) / F9 = 2  =>  0 pairs (X)
A4,H4: 2.. / A4 = 2  =>  0 pairs (*) / H4 = 2  =>  0 pairs (X)
A8,E8: 2.. / A8 = 2  =>  0 pairs (X) / E8 = 2  =>  0 pairs (_)
E2,E8: 2.. / E2 = 2  =>  0 pairs (X) / E8 = 2  =>  0 pairs (_)
F1,F3: 3.. / F1 = 3  =>  0 pairs (X) / F3 = 3  => 15 pairs (_)
E5,E6: 3.. / E5 = 3  => 13 pairs (_) / E6 = 3  => 13 pairs (_)
D7,D9: 3.. / D7 = 3  => 11 pairs (_) / D9 = 3  => 13 pairs (_)
C2,I2: 3.. / C2 = 3  => 11 pairs (_) / I2 = 3  => 13 pairs (_)
C7,D7: 3.. / C7 = 3  => 13 pairs (_) / D7 = 3  => 11 pairs (_)
I2,I3: 6.. / I2 = 6  => 11 pairs (_) / I3 = 6  => 13 pairs (_)
H5,H6: 6.. / H5 = 6  => 14 pairs (_) / H6 = 6  => 14 pairs (_)
C2,I2: 6.. / C2 = 6  => 13 pairs (_) / I2 = 6  => 11 pairs (_)
C6,H6: 6.. / C6 = 6  => 14 pairs (_) / H6 = 6  => 14 pairs (_)
A3,A5: 6.. / A3 = 6  => 11 pairs (_) / A5 = 6  => 13 pairs (_)
E8,F9: 7.. / E8 = 7  =>  0 pairs (X) / F9 = 7  =>  0 pairs (_)
A8,E8: 7.. / A8 = 7  =>  0 pairs (*) / E8 = 7  =>  0 pairs (X)
E2,E8: 7.. / E2 = 7  =>  0 pairs (*) / E8 = 7  =>  0 pairs (X)
E5,E6: 8.. / E5 = 8  => 13 pairs (_) / E6 = 8  => 13 pairs (_)
D7,D9: 8.. / D7 = 8  => 13 pairs (_) / D9 = 8  => 11 pairs (_)
C6,E6: 8.. / C6 = 8  => 13 pairs (_) / E6 = 8  => 13 pairs (_)
C7,D7: 8.. / C7 = 8  => 11 pairs (_) / D7 = 8  => 13 pairs (_)
A5,A9: 8.. / A5 = 8  => 11 pairs (_) / A9 = 8  => 13 pairs (_)
B2,G2: 9.. / B2 = 9  => 16 pairs (_) / G2 = 9  => 17 pairs (_)
A4,H4: 9.. / A4 = 9  => 15 pairs (_) / H4 = 9  =>  0 pairs (*)
B2,B9: 9.. / B2 = 9  => 16 pairs (_) / B9 = 9  => 17 pairs (_)
* DURATION: 0:00:49.773498  START: 18:13:01.248689  END: 18:13:51.022187 2017-05-04
* CP COUNT: (25)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A8,B6,C2,C7,D7,D9,E2,E5,E6,E8,F9,H4,I2)
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
* PAIR C2: 3,6 BLK 1
A3: 3,6,2,7,9                            # reduction candidate for 3,6
A3: 3,6                                  # 19 pairs
C3: 3,6,2,7,9                            # reduction candidate for 3,6
C3: 3,6 => CTR
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
C3: 2,7,9                                # 14 pairs
* PAIR E2: 2,7 BLK 2
F1: 2,7,3                                # reduction candidate for 2,7
F1: 2,7                                  # 15 pairs
F3: 2,7,3                                # reduction candidate for 2,7
F3: 2,7 => CTR
* 28169357457.428.1..4.15..8.934761825.572.41.912.5.94.746..15.92.159.6348....4.651
F3: 3                                    # 15 pairs
* PAIR E2: 2,7 ROW 2
B2: 2,7,9                                # reduction candidate for 2,7
B2: 2,7                                  # 17 pairs
G2: 2,7,9                                # reduction candidate for 2,7
G2: 2,7                                  # 16 pairs
* PAIR I2: 3,6 BLK 3
I3: 3,6,2,7,9                            # reduction candidate for 3,6
I3: 3,6                                  # 26 pairs
I3: 2,7,9                                # 11 pairs
* PAIR A4: 2,9 COL A
A3: 2,9,3,6,7                            # reduction candidate for 2,9
A3: 2,9 => SOLVED
* 381692574526478913947153286234761895659284137178539462463815729715926348892347651
A3: 3,6,7                                # 14 pairs
A9: 2,9,3,7,8                            # reduction candidate for 2,9
A9: 2,9 => CTR
* 38169.5.45..4.8.1.64.15..8..347618.585.2341..1..5894..46..15....159.6348....4.651
A9: 3,7,8                                # 14 pairs
* PAIR B6: 2,7 BLK 4
C6: 2,7,6,8                              # reduction candidate for 2,7
C6: 6,8                                  # 18 pairs
C6: 2,7                                  # 11 pairs
* PAIR B6: 2,7 ROW 6
H6: 2,7,3,6                              # reduction candidate for 2,7
H6: 2,7                                  # 14 pairs
I6: 2,7,3                                # reduction candidate for 2,7
I6: 2,7                                  # 20 pairs
* PAIR B6: 2,7 COL B
B2: 2,7,9                                # reduction candidate for 2,7
B2: 2,7                                  # 17 pairs
B9: 2,7,9                                # reduction candidate for 2,7
B9: 2,7                                  # 16 pairs
* PAIR H4: 2,9 COL H
H7: 2,9,7                                # reduction candidate for 2,9
H7: 7                                    # 18 pairs
H7: 2,9                                  # 16 pairs
* PAIR C7: 3,8 BLK 7
A9: 3,8,2,7,9                            # reduction candidate for 3,8
A9: 3,8                                  # 15 pairs
C9: 3,8,2,7,9                            # reduction candidate for 3,8
C9: 3,8 => CTR
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
C9: 2,7,9                                # 15 pairs
* PAIR A8: 2,7 BLK 7
A9: 2,7,3,8,9                            # reduction candidate for 2,7
A9: 2,7 => CTR
* 38169.5.45..4.8.1.64.15..8.93476182585.2341..1..5894..46..15....159.6348....4.651
A9: 3,8,9                                # 14 pairs
B9: 2,7,9                                # reduction candidate for 2,7
B9: 2,7                                  # 16 pairs
C9: 2,7,3,8,9                            # reduction candidate for 2,7
C9: 2,7                                  # 19 pairs
* PAIR A8: 2,7 COL A
A1: 2,7,3                                # reduction candidate for 2,7
A1: 2,7                                  # 19 pairs
A3: 2,7,3,6,9                            # reduction candidate for 2,7
A3: 2,7 => CTR
* 3816925745.6478.13.4.153.8693476182565728413912853946746381579271592634889.34.651
A3: 3,6,9                                # 14 pairs
* PAIR D9: 3,8 ROW 9
A9: 3,8,2,7,9                            # reduction candidate for 3,8
A9: 3,8                                  # 15 pairs
C9: 3,8,2,7,9                            # reduction candidate for 3,8
C9: 3,8 => CTR
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
C9: 2,7,9                                # 15 pairs
* PAIR F9: 2,7 ROW 9
A9: 2,7,3,8,9                            # reduction candidate for 2,7
A9: 2,7 => CTR
* 38169.5.45..4.8.1.64.15..8.93476182585.2341..1..5894..46..15....159.6348....4.651
A9: 3,8,9                                # 14 pairs
B9: 2,7,9                                # reduction candidate for 2,7
B9: 2,7                                  # 16 pairs
C9: 2,7,3,8,9                            # reduction candidate for 2,7
C9: 2,7                                  # 19 pairs
* PAIR F9: 2,7 COL F
F1: 2,7,3                                # reduction candidate for 2,7
F1: 2,7                                  # 15 pairs
F3: 2,7,3                                # reduction candidate for 2,7
F3: 2,7 => CTR
* 28169357457.428.1..4.15..8.934761825.572.41.912.5.94.746..15.92.159.6348....4.651
F3: 3                                    # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-453-base-pr-000.dot
* REASONING
* DIS # C3: 3,6 => CTR => C3: 2,7,9
* DIS # F3: 2,7 => CTR => F3: 3
* PRF # A3: 2,9 => SOL
* DIS # A9: 2,9 => CTR => A9: 3,7,8
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* DIS # A3: 2,7 => CTR => A3: 3,6,9
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* DIS # F3: 2,7 => CTR => F3: 3
* CNT  10 HDP CHAINS /  42 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A8,B6,C2,C7,D7,D9,E2,E5,E6,E8,F9,H4,I2)
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
* PAIR C2: 3,6 BLK 1
A3: 3,6,2,7,9                            # reduction candidate for 3,6
A3: 3,6                                  # 19 pairs
C3: 3,6,2,7,9                            # reduction candidate for 3,6
C3: 3,6 => CTR
* .8169.5.45..4.8.1..4.15..8..347618.5.5.2.41..1..5.94..46..15....159.6348....4.651
* RESTART
* PAIR C2: 3,6 BLK 1
A3: 3,6,2,7,9                            # reduction candidate for 3,6
A3: 3,6                                  # 19 pairs
A3: 2,7,9                                # 14 pairs
* PAIR E2: 2,7 BLK 2
F1: 2,7,3                                # reduction candidate for 2,7
F1: 2,7                                  # 15 pairs
F3: 2,7,3                                # reduction candidate for 2,7
F3: 2,7 => CTR
* 28169357457.428.1..4.15..8.934761825.572.41.912.5.94.746..15.92.159.6348....4.651
* RESTART
* PAIR E2: 2,7 ROW 2
B2: 2,7,9                                # reduction candidate for 2,7
B2: 2,7                                  # 18 pairs
G2: 2,7,9                                # reduction candidate for 2,7
G2: 2,7                                  # 18 pairs
* PAIR A4: 2,9 COL A
A3: 2,9,6,7                              # reduction candidate for 2,9
A3: 2,9 => SOLVED
* 381692574526478913947153286234761895659284137178539462463815729715926348892347651
* DURATION: 0:00:10.746597  START: 18:14:32.067939  END: 18:14:42.814536 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-453-base-pr-001.dot
* REASONING
* DIS # C3: 3,6 => CTR => C3: 2,7,9
* DIS C3: 2,7,9 # F3: 2,7 => CTR => F3: 3
* PRF C3: 2,7,9 + F3: 3 # A3: 2,9 => SOL
* STA C3: 2,7,9 + F3: 3 + A3: 2,9
* CNT   3 HDP CHAINS /   9 HYP OPENED

Header Info

Top 500 Minimum 17 453

solution: 381692574526478913947153286234761895659284137178539462463815729715926348892347651
info: 95454    FNBHYK   S8.f     23843

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

Solution

position: 381692574526478913947153286234761895659284137178539462463815729715926348892347651 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 # A3: 3,6 => UNS
* DIS # C3: 3,6 => CTR => C3: 2,7,9
* INC # C3: 2,7,9 => UNS
* INC # F1: 2,7 => UNS
* DIS # F3: 2,7 => CTR => F3: 3
* INC # F3: 3 => UNS
* INC # B2: 2,7 => UNS
* INC # G2: 2,7 => UNS
* INC # I3: 3,6 => UNS
* INC # I3: 2,7,9 => UNS
* PRF # A3: 2,9 => SOL
* INC # A3: 3,6,7 => UNS
* DIS # A9: 2,9 => CTR => A9: 3,7,8
* INC # A9: 3,7,8 => UNS
* INC # C6: 2,7 => UNS
* INC # C6: 6,8 => UNS
* INC # H6: 2,7 => UNS
* INC # I6: 2,7 => UNS
* INC # B2: 2,7 => UNS
* INC # B9: 2,7 => UNS
* INC # H7: 2,9 => UNS
* INC # H7: 7 => UNS
* INC # A9: 3,8 => UNS
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* INC # C9: 2,7,9 => UNS
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* INC # A9: 3,8,9 => UNS
* INC # B9: 2,7 => UNS
* INC # C9: 2,7 => UNS
* INC # A1: 2,7 => UNS
* DIS # A3: 2,7 => CTR => A3: 3,6,9
* INC # A3: 3,6,9 => UNS
* INC # A9: 3,8 => UNS
* DIS # C9: 3,8 => CTR => C9: 2,7,9
* INC # C9: 2,7,9 => UNS
* DIS # A9: 2,7 => CTR => A9: 3,8,9
* INC # A9: 3,8,9 => UNS
* INC # B9: 2,7 => UNS
* INC # C9: 2,7 => UNS
* INC # F1: 2,7 => UNS
* DIS # F3: 2,7 => CTR => F3: 3
* INC # F3: 3 => UNS
* CNT  42 HDP CHAINS /  42 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 3,6 => UNS
* DIS # C3: 3,6 => CTR => C3: 2,7,9
* INC C3: 2,7,9 # A3: 3,6 => UNS
* INC C3: 2,7,9 # A3: 2,7,9 => UNS
* INC C3: 2,7,9 # F1: 2,7 => UNS
* DIS C3: 2,7,9 # F3: 2,7 => CTR => F3: 3
* INC C3: 2,7,9 + F3: 3 # B2: 2,7 => UNS
* INC C3: 2,7,9 + F3: 3 # G2: 2,7 => UNS
* PRF C3: 2,7,9 + F3: 3 # A3: 2,9 => SOL
* STA C3: 2,7,9 + F3: 3 + A3: 2,9
* CNT   9 HDP CHAINS /   9 HYP OPENED