Analysis of xx-top500-231-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .3..9....7.......4.......1.2...6.8.....5..9..1...........1.4....9....3...5.7..... initial

Autosolve

position: 534.917..71.3.5.949...47513279463851.4351.9.71.597.43.3.7154..9491..6375.5.73914. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # I1: 2,6 => SOL
* PRF # D3: 6 => SOL
* PRF # C2: 6 => SOL
* PRF # I1: 2,6 => SOL
* DIS # B3: 6,8 => CTR => B3: 2
* PRF # H7: 2,6 => SOL
* PRF # I1: 2,6 => SOL
* DIS # C9: 6,8 => CTR => C9: 2
* DIS # I9: 2 => CTR => I9: 6,8
* PRF # D3: 6 => SOL
* PRF # H7: 2,6 => SOL
* PRF # B7: 8 => SOL
* CNT  12 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:

* PRF # I1: 2,6 => SOL
* STA I1: 2,6
* CNT   1 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

.3..9....7.......4.......1.2...6.8.....5..9..1...........1.4....9....3...5.7..... initial
534.917..71.3.5.949...47513279463851.4351.9.71.597.43.3.7154..9491..6375.5.73914. autosolve
534291786716385294928647513279463851843512967165978432387154629491826375652739148 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
D1: 2,6
E2: 2,8
G2: 2,6
A5: 6,8
B6: 6,8
F5: 2,8
F6: 2,8
H5: 2,6
I6: 2,6
A9: 6,8
D8: 2,8
E8: 2,8
G7: 2,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F5,F6: 2.. / F5 = 2  =>  0 pairs (*) / F6 = 2  =>  0 pairs (X)
H5,I6: 2.. / H5 = 2  =>  0 pairs (X) / I6 = 2  =>  0 pairs (_)
B7,C9: 2.. / B7 = 2  =>  0 pairs (X) / C9 = 2  => 18 pairs (_)
D8,E8: 2.. / D8 = 2  => 12 pairs (_) / E8 = 2  => 12 pairs (_)
F5,H5: 2.. / F5 = 2  =>  0 pairs (*) / H5 = 2  =>  0 pairs (X)
F6,I6: 2.. / F6 = 2  =>  0 pairs (X) / I6 = 2  =>  0 pairs (_)
C9,I9: 2.. / C9 = 2  => 18 pairs (_) / I9 = 2  =>  0 pairs (X)
B3,B7: 2.. / B3 = 2  => 18 pairs (_) / B7 = 2  =>  0 pairs (X)
E2,E8: 2.. / E2 = 2  => 12 pairs (_) / E8 = 2  => 12 pairs (_)
G2,G7: 2.. / G2 = 2  =>  0 pairs (*) / G7 = 2  =>  0 pairs (X)
D1,D3: 6.. / D1 = 6  => 12 pairs (_) / D3 = 6  =>  0 pairs (*)
A5,B6: 6.. / A5 = 6  =>  0 pairs (X) / B6 = 6  =>  0 pairs (_)
H5,I6: 6.. / H5 = 6  =>  0 pairs (*) / I6 = 6  =>  0 pairs (X)
C2,G2: 6.. / C2 = 6  =>  0 pairs (*) / G2 = 6  =>  0 pairs (X)
A5,H5: 6.. / A5 = 6  =>  0 pairs (X) / H5 = 6  =>  0 pairs (_)
B6,I6: 6.. / B6 = 6  =>  0 pairs (*) / I6 = 6  =>  0 pairs (X)
A5,A9: 6.. / A5 = 6  =>  0 pairs (X) / A9 = 6  =>  0 pairs (_)
G2,G7: 6.. / G2 = 6  => 12 pairs (_) / G7 = 6  =>  0 pairs (*)
E2,D3: 8.. / E2 = 8  => 12 pairs (_) / D3 = 8  => 12 pairs (_)
H1,I1: 8.. / H1 = 8  =>  0 pairs (*) / I1 = 8  =>  0 pairs (X)
A5,B6: 8.. / A5 = 8  =>  0 pairs (*) / B6 = 8  =>  0 pairs (X)
F5,F6: 8.. / F5 = 8  =>  0 pairs (X) / F6 = 8  =>  0 pairs (_)
D8,E8: 8.. / D8 = 8  => 12 pairs (_) / E8 = 8  => 12 pairs (_)
H7,I9: 8.. / H7 = 8  => 16 pairs (_) / I9 = 8  =>  0 pairs (*)
C2,E2: 8.. / C2 = 8  => 12 pairs (_) / E2 = 8  => 12 pairs (_)
A5,F5: 8.. / A5 = 8  =>  0 pairs (*) / F5 = 8  =>  0 pairs (X)
B6,F6: 8.. / B6 = 8  =>  0 pairs (X) / F6 = 8  =>  0 pairs (_)
B7,H7: 8.. / B7 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
A5,A9: 8.. / A5 = 8  =>  0 pairs (*) / A9 = 8  =>  0 pairs (X)
D3,D8: 8.. / D3 = 8  => 12 pairs (_) / D8 = 8  => 12 pairs (_)
E2,E8: 8.. / E2 = 8  => 12 pairs (_) / E8 = 8  => 12 pairs (_)
H1,H7: 8.. / H1 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
I1,I9: 8.. / I1 = 8  => 16 pairs (_) / I9 = 8  =>  0 pairs (*)
* DURATION: 0:00:55.167543  START: 10:43:54.408935  END: 10:44:49.576478 2017-05-04
* CP COUNT: (33)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A9,B6,D1,D8,E2,E8,F5,F6,G2,G7,H5,I6)
* 534.917..71.3.5.949...47513279463851.4351.9.71.597.43.3.7154..9491..6375.5.73914.
* PAIR D1: 2,6 BLK 2
D3: 2,6,8                                # reduction candidate for 2,6
D3: 8                                    # 12 pairs
D3: 2,6                                  # 12 pairs
* PAIR D1: 2,6 ROW 1
H1: 2,6,8                                # reduction candidate for 2,6
H1: 2,6                                  # 16 pairs
I1: 2,6,8                                # reduction candidate for 2,6
I1: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
I1: 8                                    # 16 pairs
* PAIR E2: 2,8 BLK 2
D3: 2,8,6                                # reduction candidate for 2,8
D3: 6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
D3: 2,8                                  # 12 pairs
* PAIR E2: 2,8 ROW 2
C2: 2,8,6                                # reduction candidate for 2,8
C2: 6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
C2: 2,8                                  # 12 pairs
* PAIR G2: 2,6 BLK 3
H1: 2,6,8                                # reduction candidate for 2,6
H1: 2,6                                  # 16 pairs
I1: 2,6,8                                # reduction candidate for 2,6
I1: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
I1: 8                                    # 16 pairs
* PAIR G2: 2,6 ROW 2
C2: 2,6,8                                # reduction candidate for 2,6
C2: 8                                    # 12 pairs
C2: 2,6                                  # 12 pairs
* PAIR B6: 6,8 COL B
B3: 6,8,2                                # reduction candidate for 6,8
B3: 6,8 => CTR
* 534.917.87163852949826475132794638518435129.71.597.43.327154689491..6375.5.739142
B3: 2                                    # 18 pairs
B7: 6,8,2                                # reduction candidate for 6,8
B7: 6,8                                  # 18 pairs
* PAIR H5: 2,6 COL H
H1: 2,6,8                                # reduction candidate for 2,6
H1: 2,6                                  # 16 pairs
H7: 2,6,8                                # reduction candidate for 2,6
H7: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
H7: 8                                    # 16 pairs
* PAIR I6: 2,6 COL I
I1: 2,6,8                                # reduction candidate for 2,6
I1: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
I1: 8                                    # 16 pairs
I9: 2,6,8                                # reduction candidate for 2,6
I9: 2,6                                  # 16 pairs
* PAIR A9: 6,8 BLK 7
B7: 6,8,2                                # reduction candidate for 6,8
B7: 6,8                                  # 18 pairs
C9: 6,8,2                                # reduction candidate for 6,8
C9: 6,8 => CTR
* 534.917.87163852949826475132794638518435129.71.597.43.327154689491..6375.5.739142
C9: 2                                    # 18 pairs
* PAIR A9: 6,8 ROW 9
I9: 6,8,2                                # reduction candidate for 6,8
I9: 2 => CTR
* 534.917687163852949.264751327946385164351892718597.4363.7154.89491..6375.5.739142
I9: 6,8                                  # 18 pairs
* PAIR D8: 2,8 COL D
D3: 2,8,6                                # reduction candidate for 2,8
D3: 6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
D3: 2,8                                  # 12 pairs
* PAIR G7: 2,6 BLK 9
H7: 2,6,8                                # reduction candidate for 2,6
H7: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
H7: 8                                    # 16 pairs
I9: 2,6,8                                # reduction candidate for 2,6
I9: 2,6                                  # 16 pairs
* PAIR G7: 2,6 ROW 7
B7: 2,6,8                                # reduction candidate for 2,6
B7: 8 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
B7: 2,6                                  # 16 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-231-base-pr-000.dot
* REASONING
* PRF # I1: 2,6 => SOL
* PRF # D3: 6 => SOL
* PRF # C2: 6 => SOL
* PRF # I1: 2,6 => SOL
* DIS # B3: 6,8 => CTR => B3: 2
* PRF # H7: 2,6 => SOL
* PRF # I1: 2,6 => SOL
* DIS # C9: 6,8 => CTR => C9: 2
* DIS # I9: 2 => CTR => I9: 6,8
* PRF # D3: 6 => SOL
* PRF # H7: 2,6 => SOL
* PRF # B7: 8 => SOL
* CNT  12 HDP CHAINS /  35 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A9,B6,D1,D8,E2,E8,F5,F6,G2,G7,H5,I6)
* 534.917..71.3.5.949...47513279463851.4351.9.71.597.43.3.7154..9491..6375.5.73914.
* PAIR D1: 2,6 BLK 2
D3: 2,6,8                                # reduction candidate for 2,6
D3: 8                                    # 12 pairs
D3: 2,6                                  # 12 pairs
* PAIR D1: 2,6 ROW 1
H1: 2,6,8                                # reduction candidate for 2,6
H1: 2,6                                  # 16 pairs
I1: 2,6,8                                # reduction candidate for 2,6
I1: 2,6 => SOLVED
* 534291786716385294928647513279463851843512967165978432387154629491826375652739148
* DURATION: 0:00:04.741425  START: 10:45:25.736846  END: 10:45:30.478271 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-231-base-pr-001.dot
* REASONING
* PRF # I1: 2,6 => SOL
* STA I1: 2,6
* CNT   1 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 231

solution: 534291786716385294928647513279463851843512967165978432387154629491826375652739148
info: 2065     FNBWXY   S8.f     17843

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

Solution

position: 534291786716385294928647513279463851843512967165978432387154629491826375652739148 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 # D3: 2,6 => UNS
* INC # D3: 8 => UNS
* INC # H1: 2,6 => UNS
* PRF # I1: 2,6 => SOL
* INC # I1: 8 => UNS
* INC # D3: 2,8 => UNS
* PRF # D3: 6 => SOL
* INC # C2: 2,8 => UNS
* PRF # C2: 6 => SOL
* INC # H1: 2,6 => UNS
* PRF # I1: 2,6 => SOL
* INC # I1: 8 => UNS
* INC # C2: 2,6 => UNS
* INC # C2: 8 => UNS
* DIS # B3: 6,8 => CTR => B3: 2
* INC # B3: 2 => UNS
* INC # B7: 6,8 => UNS
* INC # H1: 2,6 => UNS
* PRF # H7: 2,6 => SOL
* INC # H7: 8 => UNS
* PRF # I1: 2,6 => SOL
* INC # I1: 8 => UNS
* INC # I9: 2,6 => UNS
* INC # B7: 6,8 => UNS
* DIS # C9: 6,8 => CTR => C9: 2
* INC # C9: 2 => UNS
* INC # I9: 6,8 => UNS
* DIS # I9: 2 => CTR => I9: 6,8
* INC # D3: 2,8 => UNS
* PRF # D3: 6 => SOL
* PRF # H7: 2,6 => SOL
* INC # H7: 8 => UNS
* INC # I9: 2,6 => UNS
* INC # B7: 2,6 => UNS
* PRF # B7: 8 => SOL
* CNT  35 HDP CHAINS /  35 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D3: 2,6 => UNS
* INC # D3: 8 => UNS
* INC # H1: 2,6 => UNS
* PRF # I1: 2,6 => SOL
* STA I1: 2,6
* CNT   4 HDP CHAINS /   4 HYP OPENED