Analysis of xx-top500-225-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 2.1.........1....7......58.....423...5..6.....8.....4.3.....6.....8........7..... initial

Autosolve

position: 271.85...8.51....7......581....423.845..6871..8.....4.3.8...67....8..1.....7..8.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B3: 6,9 => CTR => B3: 3,4
* DIS # C3: 6,9 => CTR => C3: 4
* DIS # D3: 2 => CTR => D3: 4,6
* DIS # E3: 3,9 => CTR => E3: 2,7
* DIS # F3: 3,9 => CTR => F3: 4,7
* DIS # B2: 3,9 => CTR => B2: 4,6
* PRF # D6: 5,9 => SOL
* DIS # D6: 3 => CTR => D6: 5,9
* PRF # D6: 3,9 => SOL
* DIS # D6: 5 => CTR => D6: 3,9
* DIS # D3: 2,4 => CTR => D3: 6
* PRF # D3: 6 => SOL
* CNT  12 HDP CHAINS /  31 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 # B3: 6,9 => CTR => B3: 3,4
* DIS B3: 3,4 # C3: 6,9 => CTR => C3: 4
* PRF B3: 3,4 + C3: 4 # F2: 3,9 => SOL
* STA B3: 3,4 + C3: 4 + F2: 3,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

2.1.........1....7......58.....423...5..6.....8.....4.3.....6.....8........7..... initial
271.85...8.51....7......581....423.845..6871..8.....4.3.8...67....8..1.....7..8.. autosolve
271485936865193427934627581197542368452368719683971245318259674749836152526714893 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (21)
A3: 6,9
D1: 4,6
E2: 3,9
G1: 4,9
G2: 2,4
H2: 2,6
A4: 1,7
C5: 2,3
A6: 6,9
C6: 2,3
D4: 5,9
D5: 3,9
E6: 1,7
F6: 1,7
H4: 5,6
I5: 2,9
G6: 2,9
I6: 5,6
A8: 5,7
A9: 1,5
D7: 2,4

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A4,B4: 1.. / A4 = 1  => 19 pairs (_) / B4 = 1  => 19 pairs (_)
E6,F6: 1.. / E6 = 1  =>  0 pairs (X) / F6 = 1  => 20 pairs (_)
A4,A9: 1.. / A4 = 1  => 19 pairs (_) / A9 = 1  => 19 pairs (_)
D3,E3: 2.. / D3 = 2  =>  0 pairs (X) / E3 = 2  => 22 pairs (_)
G2,H2: 2.. / G2 = 2  =>  0 pairs (X) / H2 = 2  =>  0 pairs (_)
C5,C6: 2.. / C5 = 2  =>  0 pairs (*) / C6 = 2  =>  0 pairs (X)
I5,G6: 2.. / I5 = 2  =>  0 pairs (X) / G6 = 2  =>  0 pairs (_)
C5,I5: 2.. / C5 = 2  =>  0 pairs (*) / I5 = 2  =>  0 pairs (X)
C6,G6: 2.. / C6 = 2  =>  0 pairs (X) / G6 = 2  =>  0 pairs (_)
D3,D7: 2.. / D3 = 2  =>  0 pairs (X) / D7 = 2  => 22 pairs (_)
G2,G6: 2.. / G2 = 2  =>  0 pairs (X) / G6 = 2  =>  0 pairs (_)
B2,B3: 3.. / B2 = 3  =>  0 pairs (X) / B3 = 3  => 21 pairs (_)
H1,I1: 3.. / H1 = 3  => 22 pairs (_) / I1 = 3  =>  0 pairs (X)
C5,C6: 3.. / C5 = 3  =>  0 pairs (X) / C6 = 3  =>  0 pairs (_)
D5,D6: 3.. / D5 = 3  =>  0 pairs (*) / D6 = 3  =>  0 pairs (X)
C5,D5: 3.. / C5 = 3  =>  0 pairs (X) / D5 = 3  =>  0 pairs (_)
C6,D6: 3.. / C6 = 3  =>  0 pairs (*) / D6 = 3  =>  0 pairs (X)
G1,G2: 4.. / G1 = 4  =>  0 pairs (X) / G2 = 4  =>  0 pairs (_)
D1,G1: 4.. / D1 = 4  =>  0 pairs (*) / G1 = 4  =>  0 pairs (X)
D4,D6: 5.. / D4 = 5  =>  0 pairs (*) / D6 = 5  =>  0 pairs (X)
H4,I6: 5.. / H4 = 5  =>  0 pairs (X) / I6 = 5  =>  0 pairs (_)
A8,A9: 5.. / A8 = 5  => 19 pairs (_) / A9 = 5  => 19 pairs (_)
D4,H4: 5.. / D4 = 5  =>  0 pairs (*) / H4 = 5  =>  0 pairs (X)
D6,I6: 5.. / D6 = 5  =>  0 pairs (X) / I6 = 5  =>  0 pairs (_)
E7,I7: 5.. / E7 = 5  => 21 pairs (_) / I7 = 5  =>  0 pairs (X)
D1,D3: 6.. / D1 = 6  =>  0 pairs (X) / D3 = 6  =>  0 pairs (_)
H4,I6: 6.. / H4 = 6  =>  0 pairs (*) / I6 = 6  =>  0 pairs (X)
F8,F9: 6.. / F8 = 6  => 21 pairs (_) / F9 = 6  => 22 pairs (_)
B2,H2: 6.. / B2 = 6  =>  0 pairs (*) / H2 = 6  =>  0 pairs (X)
A6,I6: 6.. / A6 = 6  =>  0 pairs (*) / I6 = 6  =>  0 pairs (X)
A3,A6: 6.. / A3 = 6  =>  0 pairs (X) / A6 = 6  =>  0 pairs (_)
I1,I6: 6.. / I1 = 6  =>  0 pairs (*) / I6 = 6  =>  0 pairs (X)
E3,F3: 7.. / E3 = 7  =>  0 pairs (X) / F3 = 7  => 20 pairs (_)
A4,C4: 7.. / A4 = 7  => 19 pairs (_) / C4 = 7  => 19 pairs (_)
E6,F6: 7.. / E6 = 7  => 20 pairs (_) / F6 = 7  =>  0 pairs (X)
A8,C8: 7.. / A8 = 7  => 19 pairs (_) / C8 = 7  => 19 pairs (_)
A4,A8: 7.. / A4 = 7  => 19 pairs (_) / A8 = 7  => 19 pairs (_)
C4,C8: 7.. / C4 = 7  => 19 pairs (_) / C8 = 7  => 19 pairs (_)
E3,E6: 7.. / E3 = 7  =>  0 pairs (X) / E6 = 7  => 20 pairs (_)
F3,F6: 7.. / F3 = 7  => 20 pairs (_) / F6 = 7  =>  0 pairs (X)
I5,G6: 9.. / I5 = 9  =>  0 pairs (*) / G6 = 9  =>  0 pairs (X)
D5,I5: 9.. / D5 = 9  =>  0 pairs (X) / I5 = 9  =>  0 pairs (_)
A3,A6: 9.. / A3 = 9  =>  0 pairs (*) / A6 = 9  =>  0 pairs (X)
G1,G6: 9.. / G1 = 9  =>  0 pairs (*) / G6 = 9  =>  0 pairs (X)
* DURATION: 0:01:32.327269  START: 10:32:02.404778  END: 10:33:34.732047 2017-05-04
* CP COUNT: (44)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,A6,A8,A9,C5,C6,D1,D4,D5,D7,E2,E6,F6,G1,G2,G6,H2,H4,I5,I6)
* 271.85...8.51....7......581....423.845..6871..8.....4.3.8...67....8..1.....7..8..
* PAIR A3: 6,9 BLK 1
B2: 6,9,3,4                              # reduction candidate for 6,9
B2: 6,9                                  # 25 pairs
B3: 6,9,3,4                              # reduction candidate for 6,9
B3: 6,9 => CTR
* 271.85...835194267..4...581....4235845..68712.82....4.3.8...67....8..1.....7..8..
B3: 3,4                                  # 22 pairs
C3: 6,9,4                                # reduction candidate for 6,9
C3: 6,9 => CTR
* 2716854..8.51..267......581....4235845..68712.82....4.3.8...67....8..1.....7..8..
C3: 4                                    # 23 pairs
* PAIR D1: 4,6 BLK 2
D3: 4,6,2                                # reduction candidate for 4,6
D3: 2 => CTR
* 2716854..8.51..267...2..581....4235845..68712.82....4.3.8...67....8..1.....7..8..
D3: 4,6                                  # 22 pairs
* PAIR E2: 3,9 BLK 2
F2: 3,9,4                                # reduction candidate for 3,9
F2: 3,9                                  # 25 pairs
E3: 3,9,2,7                              # reduction candidate for 3,9
E3: 3,9 => CTR
* 2716854..8.51.4267...2.7581....4235845..68712.82.71.4.3.84.967....8..1.....7..8..
E3: 2,7                                  # 22 pairs
F3: 3,9,4,7                              # reduction candidate for 3,9
F3: 3,9 => CTR
* 2716854..8.51.4267...27.581....4235845..68712.82.17.4.3.84..67....8..1.....7..8..
F3: 4,7                                  # 22 pairs
* PAIR E2: 3,9 ROW 2
B2: 3,9,4,6                              # reduction candidate for 3,9
B2: 3,9 => CTR
* 2716854..8.51.42676..2..581...94235845.36871..8.5...463.8...67....8..1.....7..8..
B2: 4,6                                  # 25 pairs
* PAIR E2: 3,9 COL E
E8: 3,9,2,5                              # reduction candidate for 3,9
E8: 3,9                                  # 23 pairs
E9: 3,9,1,2,5                            # reduction candidate for 3,9
E9: 3,9                                  # 24 pairs
* PAIR A6: 6,9 BLK 4
B4: 6,9,1                                # reduction candidate for 6,9
B4: 6,9                                  # 19 pairs
C4: 6,9,7                                # reduction candidate for 6,9
C4: 6,9                                  # 19 pairs
* PAIR D4: 5,9 BLK 5
D6: 5,9,3                                # reduction candidate for 5,9
D6: 5,9 => SOLVED
* 271485936865193427934627581197542368452368719683971245318259674749836152526714893
D6: 3 => CTR
* 271.854.68.51....7......581...54236845.9687126823..9453.8.5.67....8..1.....7..8..
* PAIR D5: 3,9 BLK 5
D6: 3,9,5                                # reduction candidate for 3,9
D6: 3,9 => SOLVED
* 271485936865193427934627581197542368452368719683971245318259674749836152526714893
D6: 5 => CTR
* 271.859.38.51..4276.....581...9423.845.3687199835..2463.8...67....8..1.....7..8..
* PAIR I5: 2,9 COL I
I7: 2,9,4,5                              # reduction candidate for 2,9
I7: 2,9                                  # 23 pairs
I8: 2,9,3,4,5                            # reduction candidate for 2,9
I8: 2,9                                  # 24 pairs
I9: 2,9,3,4,5                            # reduction candidate for 2,9
I9: 2,9                                  # 24 pairs
* PAIR A9: 1,5 ROW 9
E9: 1,5,2,3,9                            # reduction candidate for 1,5
E9: 1,5                                  # 22 pairs
E9: 2,3,9                                # 21 pairs
* PAIR D7: 2,4 ROW 7
B7: 2,4,1,9                              # reduction candidate for 2,4
B7: 2,4                                  # 24 pairs
I7: 2,4,5,9                              # reduction candidate for 2,4
I7: 2,4                                  # 24 pairs
* PAIR D7: 2,4 COL D
D3: 2,4,6                                # reduction candidate for 2,4
D3: 2,4 => CTR
* 2716854..8.51..267......581....4235845..68712.82....4.3.8...67....8..1.....7..8..
D3: 6 => SOLVED
* 271485936865193427934627581197542368452368719683971245318259674749836152526714893
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-225-base-pr-000.dot
* REASONING
* DIS # B3: 6,9 => CTR => B3: 3,4
* DIS # C3: 6,9 => CTR => C3: 4
* DIS # D3: 2 => CTR => D3: 4,6
* DIS # E3: 3,9 => CTR => E3: 2,7
* DIS # F3: 3,9 => CTR => F3: 4,7
* DIS # B2: 3,9 => CTR => B2: 4,6
* PRF # D6: 5,9 => SOL
* DIS # D6: 3 => CTR => D6: 5,9
* PRF # D6: 3,9 => SOL
* DIS # D6: 5 => CTR => D6: 3,9
* DIS # D3: 2,4 => CTR => D3: 6
* PRF # D3: 6 => SOL
* CNT  12 HDP CHAINS /  31 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,A6,A8,A9,C5,C6,D1,D4,D5,D7,E2,E6,F6,G1,G2,G6,H2,H4,I5,I6)
* 271.85...8.51....7......581....423.845..6871..8.....4.3.8...67....8..1.....7..8..
* PAIR A3: 6,9 BLK 1
B2: 6,9,3,4                              # reduction candidate for 6,9
B2: 6,9                                  # 25 pairs
B3: 6,9,3,4                              # reduction candidate for 6,9
B3: 6,9 => CTR
* 271.85...835194267..4...581....4235845..68712.82....4.3.8...67....8..1.....7..8..
C3: 6,9,4                                # reduction candidate for 6,9
C3: 6,9 => CTR
* 2716854..8.51..267......581....4235845..68712.82....4.3.8...67....8..1.....7..8..
* RESTART
* PAIR E2: 3,9 BLK 2
F2: 3,9,4                                # reduction candidate for 3,9
F2: 3,9 => SOLVED
* 271485936865193427934627581197542368452368719683971245318259674749836152526714893
* DURATION: 0:00:06.215198  START: 10:34:11.255416  END: 10:34:17.470614 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-225-base-pr-001.dot
* REASONING
* DIS # B3: 6,9 => CTR => B3: 3,4
* DIS B3: 3,4 # C3: 6,9 => CTR => C3: 4
* PRF B3: 3,4 + C3: 4 # F2: 3,9 => SOL
* STA B3: 3,4 + C3: 4 + F2: 3,9
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 225

solution: 271485936865193427934627581197542368452368719683971245318259674749836152526714893
info: 2040     FNBTHWY  S8.f     27982

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

Solution

position: 271485936865193427934627581197542368452368719683971245318259674749836152526714893 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 # B2: 6,9 => UNS
* DIS # B3: 6,9 => CTR => B3: 3,4
* INC # B3: 3,4 => UNS
* DIS # C3: 6,9 => CTR => C3: 4
* INC # C3: 4 => UNS
* INC # D3: 4,6 => UNS
* DIS # D3: 2 => CTR => D3: 4,6
* INC # F2: 3,9 => UNS
* DIS # E3: 3,9 => CTR => E3: 2,7
* INC # E3: 2,7 => UNS
* DIS # F3: 3,9 => CTR => F3: 4,7
* INC # F3: 4,7 => UNS
* DIS # B2: 3,9 => CTR => B2: 4,6
* INC # B2: 4,6 => UNS
* INC # E8: 3,9 => UNS
* INC # E9: 3,9 => UNS
* INC # B4: 6,9 => UNS
* INC # C4: 6,9 => UNS
* PRF # D6: 5,9 => SOL
* DIS # D6: 3 => CTR => D6: 5,9
* PRF # D6: 3,9 => SOL
* DIS # D6: 5 => CTR => D6: 3,9
* INC # I7: 2,9 => UNS
* INC # I8: 2,9 => UNS
* INC # I9: 2,9 => UNS
* INC # E9: 1,5 => UNS
* INC # E9: 2,3,9 => UNS
* INC # B7: 2,4 => UNS
* INC # I7: 2,4 => UNS
* DIS # D3: 2,4 => CTR => D3: 6
* PRF # D3: 6 => SOL
* CNT  31 HDP CHAINS /  31 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B2: 6,9 => UNS
* DIS # B3: 6,9 => CTR => B3: 3,4
* DIS B3: 3,4 # C3: 6,9 => CTR => C3: 4
* PRF B3: 3,4 + C3: 4 # F2: 3,9 => SOL
* STA B3: 3,4 + C3: 4 + F2: 3,9
* CNT   4 HDP CHAINS /   4 HYP OPENED