Analysis of xx-top500-457-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .6...1..........2.......4.....47.8...9......1...8.....4..73....1.....59.........6 initial

Autosolve

position: .6..41....4.....2.....2.4.....47.8..894.....1...81...4459736...1.628459....195.46 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D2: 5,6 => CTR => D2: 3,9
* DIS # C2: 7,8 => CTR => C2: 1,3,5
* DIS # D2: 5,6 => CTR => D2: 3,9
* DIS # F4: 2,3 => CTR => F4: 9
* DIS # G5: 7 => CTR => G5: 2,3
* DIS # G5: 3,7 => CTR => G5: 2
* DIS # G5: 3,7 => CTR => G5: 2
* CNT   7 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 # D2: 5,6 => CTR => D2: 3,9
* DIS D2: 3,9 # D3: 3,9 => CTR => D3: 5,6
* DIS D2: 3,9 + D3: 5,6 # C2: 7,8 => CTR => C2: 1,3,5
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I3: 7,8 => CTR => I3: 3,5,9
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 # F4: 2,3 => CTR => F4: 9
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 # I2: 9 => CTR => I2: 3,7
* PRF D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 # A1: 2,7 => SOL
* STA D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 + A1: 2,7
* CNT   7 HDP CHAINS /  19 HYP OPENED

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

Details

Positions

.6...1..........2.......4.....47.8...9......1...8.....4..73....1.....59.........6 initial
.6..41....4.....2.....2.4.....47.8..894.....1...81...4459736...1.628459....195.46 autosolve
267941358941358627583627419612479835894563271735812964459736182176284593328195746 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
E2: 5,6
F2: 7,8
F3: 7,8
G2: 1,6
H3: 1,6
D5: 5,6
E5: 5,6
F5: 2,3
H5: 3,7
B8: 3,7
G7: 1,2
H7: 1,8
I7: 2,8
I8: 3,7
G9: 3,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G2,H3: 1.. / G2 = 1  =>  0 pairs (X) / H3 = 1  =>  9 pairs (_)
B4,C4: 1.. / B4 = 1  => 15 pairs (_) / C4 = 1  =>  0 pairs (X)
G7,H7: 1.. / G7 = 1  =>  9 pairs (_) / H7 = 1  =>  0 pairs (X)
C2,G2: 1.. / C2 = 1  =>  9 pairs (_) / G2 = 1  =>  0 pairs (X)
B3,B4: 1.. / B3 = 1  =>  0 pairs (X) / B4 = 1  => 15 pairs (_)
G2,G7: 1.. / G2 = 1  =>  0 pairs (X) / G7 = 1  =>  9 pairs (_)
H3,H7: 1.. / H3 = 1  =>  9 pairs (_) / H7 = 1  =>  0 pairs (X)
A1,C1: 2.. / A1 = 2  => 18 pairs (_) / C1 = 2  => 15 pairs (_)
G7,I7: 2.. / G7 = 2  =>  0 pairs (X) / I7 = 2  =>  9 pairs (_)
F5,G5: 2.. / F5 = 2  =>  0 pairs (X) / G5 = 2  => 11 pairs (_)
I4,I7: 2.. / I4 = 2  =>  0 pairs (X) / I7 = 2  =>  9 pairs (_)
I8,G9: 3.. / I8 = 3  => 16 pairs (_) / G9 = 3  => 17 pairs (_)
B8,I8: 3.. / B8 = 3  => 17 pairs (_) / I8 = 3  => 16 pairs (_)
D5,E5: 5.. / D5 = 5  => 13 pairs (_) / E5 = 5  =>  0 pairs (X)
E2,E5: 5.. / E2 = 5  => 13 pairs (_) / E5 = 5  =>  0 pairs (X)
G2,H3: 6.. / G2 = 6  =>  9 pairs (_) / H3 = 6  =>  0 pairs (X)
A4,A6: 6.. / A4 = 6  => 16 pairs (_) / A6 = 6  => 10 pairs (_)
D5,E5: 6.. / D5 = 6  =>  0 pairs (X) / E5 = 6  => 13 pairs (_)
D3,H3: 6.. / D3 = 6  =>  9 pairs (_) / H3 = 6  =>  0 pairs (X)
A4,H4: 6.. / A4 = 6  => 16 pairs (_) / H4 = 6  => 10 pairs (_)
E2,E5: 6.. / E2 = 6  =>  0 pairs (X) / E5 = 6  => 13 pairs (_)
G2,G6: 6.. / G2 = 6  =>  9 pairs (_) / G6 = 6  =>  0 pairs (X)
F2,F3: 7.. / F2 = 7  => 13 pairs (_) / F3 = 7  => 13 pairs (_)
G5,H5: 7.. / G5 = 7  =>  0 pairs (X) / H5 = 7  => 15 pairs (_)
I8,G9: 7.. / I8 = 7  => 17 pairs (_) / G9 = 7  => 16 pairs (_)
B8,I8: 7.. / B8 = 7  => 16 pairs (_) / I8 = 7  => 17 pairs (_)
H1,H5: 7.. / H1 = 7  =>  0 pairs (X) / H5 = 7  => 15 pairs (_)
F2,F3: 8.. / F2 = 8  => 13 pairs (_) / F3 = 8  => 13 pairs (_)
B9,C9: 8.. / B9 = 8  => 15 pairs (_) / C9 = 8  => 13 pairs (_)
H7,I7: 8.. / H7 = 8  =>  9 pairs (_) / I7 = 8  =>  0 pairs (X)
B3,B9: 8.. / B3 = 8  => 13 pairs (_) / B9 = 8  => 15 pairs (_)
H1,H7: 8.. / H1 = 8  =>  0 pairs (X) / H7 = 8  =>  9 pairs (_)
F4,F6: 9.. / F4 = 9  => 11 pairs (_) / F6 = 9  =>  0 pairs (X)
I4,G6: 9.. / I4 = 9  =>  0 pairs (X) / G6 = 9  => 11 pairs (_)
F4,I4: 9.. / F4 = 9  => 11 pairs (_) / I4 = 9  =>  0 pairs (X)
F6,G6: 9.. / F6 = 9  =>  0 pairs (X) / G6 = 9  => 11 pairs (_)
G1,G6: 9.. / G1 = 9  =>  0 pairs (X) / G6 = 9  => 11 pairs (_)
* DURATION: 0:01:11.514804  START: 18:21:55.827437  END: 18:23:07.342241 2017-05-04
* CP COUNT: (37)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B8,D5,E2,E5,F2,F3,F5,G2,G7,G9,H3,H5,H7,I7,I8)
* .6..41....4.....2.....2.4.....47.8..894.....1...81...4459736...1.628459....195.46
* PAIR E2: 5,6 BLK 2
D2: 5,6,3,9                              # reduction candidate for 5,6
D2: 5,6 => CTR
* .6..41....4....12.....2.46.6..47.8..894.....1...81.6.44597362181.628459....195.46
D2: 3,9                                  # 16 pairs
D3: 5,6,3,9                              # reduction candidate for 5,6
D3: 5,6                                  # 18 pairs
* PAIR F2: 7,8 ROW 2
C2: 7,8,1,3,5                            # reduction candidate for 7,8
C2: 7,8 => CTR
* .6..41....4....12.....2.46.6..47.8..894.....1...81.6.44597362181.628459....195.46
C2: 1,3,5                                # 15 pairs
I2: 7,8,3,5,9                            # reduction candidate for 7,8
I2: 7,8                                  # 16 pairs
* PAIR F3: 7,8 ROW 3
B3: 7,8,1,3                              # reduction candidate for 7,8
B3: 7,8                                  # 16 pairs
C3: 7,8,1,3,5                            # reduction candidate for 7,8
C3: 7,8                                  # 17 pairs
I3: 7,8,3,5,9                            # reduction candidate for 7,8
I3: 7,8                                  # 17 pairs
* PAIR D5: 5,6 COL D
D2: 5,6,3,9                              # reduction candidate for 5,6
D2: 5,6 => CTR
* .6..41....4....12.....2.46.6..47.8..894.....1...81.6.44597362181.628459....195.46
D2: 3,9                                  # 16 pairs
D3: 5,6,3,9                              # reduction candidate for 5,6
D3: 5,6                                  # 18 pairs
* PAIR F5: 2,3 BLK 5
F4: 2,3,9                                # reduction candidate for 2,3
F4: 2,3 => CTR
* .6.341978.41958623983627415.1.4738.9894562731375819264459736182136284597728195346
F4: 9                                    # 11 pairs
F6: 2,3,9                                # reduction candidate for 2,3
F6: 2,3                                  # 11 pairs
* PAIR F5: 2,3 ROW 5
G5: 2,3,7                                # reduction candidate for 2,3
G5: 7 => CTR
* .6.341978.4195862398.62.41..1.4738.9894562731.7.8192.4459736182136284597.28195346
G5: 2,3                                  # 15 pairs
* PAIR H5: 3,7 BLK 6
G5: 3,7,2                                # reduction candidate for 3,7
G5: 3,7 => CTR
* .6.341978.41958623983627415.1.4738.9894562731..78192.44597361821.628459..28195.46
G5: 2                                    # 11 pairs
* PAIR H5: 3,7 COL H
H1: 3,7,5,8                              # reduction candidate for 3,7
H1: 3,7                                  # 19 pairs
H1: 5,8                                  # 13 pairs
* PAIR B8: 3,7 BLK 7
A9: 3,7,2                                # reduction candidate for 3,7
A9: 3,7                                  # 18 pairs
B9: 3,7,2,8                              # reduction candidate for 3,7
B9: 3,7                                  # 18 pairs
C9: 3,7,2,8                              # reduction candidate for 3,7
C9: 3,7                                  # 16 pairs
* PAIR B8: 3,7 COL B
B3: 3,7,1,8                              # reduction candidate for 3,7
B3: 3,7                                  # 20 pairs
B6: 3,7,2                                # reduction candidate for 3,7
B6: 3,7                                  # 19 pairs
* PAIR I8: 3,7 COL I
I1: 3,7,5,8,9                            # reduction candidate for 3,7
I1: 3,7                                  # 17 pairs
I2: 3,7,5,8,9                            # reduction candidate for 3,7
I2: 3,7                                  # 16 pairs
I3: 3,7,5,8,9                            # reduction candidate for 3,7
I3: 3,7                                  # 16 pairs
* PAIR G9: 3,7 ROW 9
A9: 3,7,2                                # reduction candidate for 3,7
A9: 3,7                                  # 18 pairs
B9: 3,7,2,8                              # reduction candidate for 3,7
B9: 3,7                                  # 18 pairs
C9: 3,7,2,8                              # reduction candidate for 3,7
C9: 3,7                                  # 16 pairs
* PAIR G9: 3,7 COL G
G1: 3,7,9                                # reduction candidate for 3,7
G1: 3,7                                  # 11 pairs
G5: 3,7,2                                # reduction candidate for 3,7
G5: 3,7 => CTR
* .6.341978.41958623983627415.1.4738.9894562731..78192.44597361821.628459..28195.46
G5: 2                                    # 11 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-457-base-pr-000.dot
* REASONING
* DIS # D2: 5,6 => CTR => D2: 3,9
* DIS # C2: 7,8 => CTR => C2: 1,3,5
* DIS # D2: 5,6 => CTR => D2: 3,9
* DIS # F4: 2,3 => CTR => F4: 9
* DIS # G5: 7 => CTR => G5: 2,3
* DIS # G5: 3,7 => CTR => G5: 2
* DIS # G5: 3,7 => CTR => G5: 2
* CNT   7 HDP CHAINS /  35 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B8,D5,E2,E5,F2,F3,F5,G2,G7,G9,H3,H5,H7,I7,I8)
* .6..41....4.....2.....2.4.....47.8..894.....1...81...4459736...1.628459....195.46
* PAIR E2: 5,6 BLK 2
D2: 5,6,3,9                              # reduction candidate for 5,6
D2: 5,6 => CTR
* .6..41....4....12.....2.46.6..47.8..894.....1...81.6.44597362181.628459....195.46
D3: 5,6,3,9                              # reduction candidate for 5,6
D3: 5,6                                  # 18 pairs
* RESTART
* PAIR E2: 5,6 BLK 2
D3: 5,6,3,9                              # reduction candidate for 5,6
D3: 3,9 => CTR
* .6..41....4..6.12.....2.46.6..47.8..89465...1...81.6.44597362181.628459....195.46
* PAIR F2: 7,8 ROW 2
C2: 7,8,1,3,5                            # reduction candidate for 7,8
C2: 7,8 => CTR
* .6..41....4....12.....2.46.6..47.8..89465...1...81.6.44597362181.628459....195.46
I2: 7,8,3,5,9                            # reduction candidate for 7,8
I2: 7,8                                  # 19 pairs
* RESTART
* PAIR F2: 7,8 ROW 2
I2: 7,8,3,5,9                            # reduction candidate for 7,8
I2: 7,8                                  # 19 pairs
I2: 3,5,9                                # 17 pairs
* PAIR RESTART
* PAIR F2: 7,8 ROW 2
I2: 7,8,3,5,9                            # reduction candidate for 7,8
I2: 7,8                                  # 19 pairs
I2: 3,5,9                                # 17 pairs
* PAIR F3: 7,8 ROW 3
B3: 7,8,1,3                              # reduction candidate for 7,8
B3: 7,8                                  # 19 pairs
C3: 7,8,1,3,5                            # reduction candidate for 7,8
C3: 7,8                                  # 20 pairs
I3: 7,8,3,5,9                            # reduction candidate for 7,8
I3: 7,8 => CTR
* 268.41..7741358629935627418.1347.8..894.....1.2781...4459736182176284593382195746
* PAIR RESTART
* PAIR F3: 7,8 ROW 3
B3: 7,8,1,3                              # reduction candidate for 7,8
B3: 7,8                                  # 19 pairs
C3: 7,8,1,3,5                            # reduction candidate for 7,8
C3: 7,8                                  # 20 pairs
* PAIR F5: 2,3 BLK 5
F4: 2,3,9                                # reduction candidate for 2,3
F4: 2,3 => CTR
* .6.341978.41958623983627415.1.4738.9894562731375819264459736182136284597728195346
* PAIR I8: 3,7 COL I
I2: 3,7,9                                # reduction candidate for 3,7
I2: 9 => CTR
* .6..417.874135862998.62741..1.4798..894563271..78129.4459736182176284593.28195.46
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A2,A3,A9,B6,B8,C1,C3,C4,D1,D2,G1,G9,H4,H6,I2,I8)
* .6..41.58.41.5862..8.627419.1.4798.5894563271...8129.44597361821.628459..28195.46
* PAIR C1: 2,7 BLK 1
A1: 2,7,9                                # reduction candidate for 2,7
A1: 2,7 => SOLVED
* 267941358941358627583627419612479835894563271735812964459736182176284593328195746
* DURATION: 0:00:23.859380  START: 18:23:44.624386  END: 18:24:08.483766 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-457-base-pr-001.dot
* REASONING
* DIS # D2: 5,6 => CTR => D2: 3,9
* DIS D2: 3,9 # D3: 3,9 => CTR => D3: 5,6
* DIS D2: 3,9 + D3: 5,6 # C2: 7,8 => CTR => C2: 1,3,5
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I3: 7,8 => CTR => I3: 3,5,9
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 # F4: 2,3 => CTR => F4: 9
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 # I2: 9 => CTR => I2: 3,7
* PRF D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 # A1: 2,7 => SOL
* STA D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 + A1: 2,7
* CNT   7 HDP CHAINS /  19 HYP OPENED

Header Info

Top 500 Minimum 17 457

solution: 267941358941358627583627419612479835894563271735812964459736182176284593328195746
info: 95500    FNBHXYK  S8.f     21056

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

Solution

position: 267941358941358627583627419612479835894563271735812964459736182176284593328195746 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 # D2: 5,6 => CTR => D2: 3,9
* INC # D2: 3,9 => UNS
* INC # D3: 5,6 => UNS
* DIS # C2: 7,8 => CTR => C2: 1,3,5
* INC # C2: 1,3,5 => UNS
* INC # I2: 7,8 => UNS
* INC # B3: 7,8 => UNS
* INC # C3: 7,8 => UNS
* INC # I3: 7,8 => UNS
* DIS # D2: 5,6 => CTR => D2: 3,9
* INC # D2: 3,9 => UNS
* INC # D3: 5,6 => UNS
* DIS # F4: 2,3 => CTR => F4: 9
* INC # F4: 9 => UNS
* INC # F6: 2,3 => UNS
* INC # G5: 2,3 => UNS
* DIS # G5: 7 => CTR => G5: 2,3
* DIS # G5: 3,7 => CTR => G5: 2
* INC # G5: 2 => UNS
* INC # H1: 3,7 => UNS
* INC # H1: 5,8 => UNS
* INC # A9: 3,7 => UNS
* INC # B9: 3,7 => UNS
* INC # C9: 3,7 => UNS
* INC # B3: 3,7 => UNS
* INC # B6: 3,7 => UNS
* INC # I1: 3,7 => UNS
* INC # I2: 3,7 => UNS
* INC # I3: 3,7 => UNS
* INC # A9: 3,7 => UNS
* INC # B9: 3,7 => UNS
* INC # C9: 3,7 => UNS
* INC # G1: 3,7 => UNS
* DIS # G5: 3,7 => CTR => G5: 2
* INC # G5: 2 => UNS
* CNT  35 HDP CHAINS /  35 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D2: 5,6 => CTR => D2: 3,9
* INC D2: 3,9 # D3: 5,6 => UNS
* INC D2: 3,9 # D3: 5,6 => UNS
* DIS D2: 3,9 # D3: 3,9 => CTR => D3: 5,6
* DIS D2: 3,9 + D3: 5,6 # C2: 7,8 => CTR => C2: 1,3,5
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I2: 7,8 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I2: 7,8 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I2: 3,5,9 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I2: 7,8 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I2: 3,5,9 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # B3: 7,8 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 # C3: 7,8 => UNS
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 # I3: 7,8 => CTR => I3: 3,5,9
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 # B3: 7,8 => UNS
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 # C3: 7,8 => UNS
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 # F4: 2,3 => CTR => F4: 9
* INC D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 # I2: 3,7 => UNS
* DIS D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 # I2: 9 => CTR => I2: 3,7
* PRF D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 # A1: 2,7 => SOL
* STA D2: 3,9 + D3: 5,6 + C2: 1,3,5 + I3: 3,5,9 + F4: 9 + I2: 3,7 + A1: 2,7
* CNT  19 HDP CHAINS /  19 HYP OPENED