Analysis of xx-top500-426-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 84.....6....7.2......3.....5...8....1.......9......2......3..4...7...3...2.9..... initial

Autosolve

position: 843.9.7629..7.2...27.3.8.9.5.2.89.7.1.4.27..97.9..32..6.823.9474978.632.32.974... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I2: 1,5 => CTR => I2: 3,4,8
* DIS # D6: 5,6 => CTR => D6: 1,4
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* PRF # I9: 1,5 => SOL
* PRF # I9: 1,5 => SOL
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* CNT   7 HDP CHAINS /  40 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 # I2: 1,5 => CTR => I2: 3,4,8
* DIS I2: 3,4,8 # D6: 5,6 => CTR => D6: 1,4
* DIS I2: 3,4,8 + D6: 1,4 # I6: 1,5 => CTR => I6: 4,6,8
* DIS I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 # H6: 8 => CTR => H6: 1,5
* PRF I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 # I9: 1,5 => SOL
* STA I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 + I9: 1,5
* CNT   5 HDP CHAINS /  29 HYP OPENED

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

Details

Positions

84.....6....7.2......3.....5...8....1.......9......2......3..4...7...3...2.9..... initial
843.9.7629..7.2...27.3.8.9.5.2.89.7.1.4.27..97.9..32..6.823.9474978.632.32.974... autosolve
843591762956742138271368594562189473134627859789453216618235947497816325325974681 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
B2: 1,5
D1: 1,5
F1: 1,5
E2: 4,6
E3: 4,6
B4: 3,6
B6: 6,8
D5: 5,6
E6: 1,5
B7: 1,5
C9: 1,5
F7: 1,5
E8: 1,5
I8: 1,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D1,F1: 1.. / D1 = 1  =>  0 pairs (X) / F1 = 1  =>  0 pairs (_)
B7,C9: 1.. / B7 = 1  =>  0 pairs (*) / C9 = 1  =>  0 pairs (X)
F7,E8: 1.. / F7 = 1  =>  0 pairs (X) / E8 = 1  =>  0 pairs (_)
B7,F7: 1.. / B7 = 1  =>  0 pairs (*) / F7 = 1  =>  0 pairs (X)
E8,I8: 1.. / E8 = 1  =>  0 pairs (*) / I8 = 1  =>  0 pairs (X)
B2,B7: 1.. / B2 = 1  =>  0 pairs (X) / B7 = 1  =>  0 pairs (_)
E6,E8: 1.. / E6 = 1  =>  0 pairs (X) / E8 = 1  =>  0 pairs (_)
F1,F7: 1.. / F1 = 1  =>  0 pairs (*) / F7 = 1  =>  0 pairs (X)
H2,I2: 3.. / H2 = 3  => 18 pairs (_) / I2 = 3  => 14 pairs (_)
B4,B5: 3.. / B4 = 3  => 14 pairs (_) / B5 = 3  => 18 pairs (_)
I4,H5: 3.. / I4 = 3  => 18 pairs (_) / H5 = 3  => 14 pairs (_)
B4,I4: 3.. / B4 = 3  => 14 pairs (_) / I4 = 3  => 18 pairs (_)
B5,H5: 3.. / B5 = 3  => 18 pairs (_) / H5 = 3  => 14 pairs (_)
H2,H5: 3.. / H2 = 3  => 18 pairs (_) / H5 = 3  => 14 pairs (_)
I2,I4: 3.. / I2 = 3  => 14 pairs (_) / I4 = 3  => 18 pairs (_)
E2,E3: 4.. / E2 = 4  => 13 pairs (_) / E3 = 4  => 18 pairs (_)
D4,D6: 4.. / D4 = 4  => 20 pairs (_) / D6 = 4  => 15 pairs (_)
D6,I6: 4.. / D6 = 4  => 15 pairs (_) / I6 = 4  => 20 pairs (_)
D1,F1: 5.. / D1 = 5  =>  0 pairs (*) / F1 = 5  =>  0 pairs (X)
B7,C9: 5.. / B7 = 5  =>  0 pairs (X) / C9 = 5  =>  0 pairs (_)
F7,E8: 5.. / F7 = 5  =>  0 pairs (*) / E8 = 5  =>  0 pairs (X)
B7,F7: 5.. / B7 = 5  =>  0 pairs (X) / F7 = 5  =>  0 pairs (_)
E8,I8: 5.. / E8 = 5  =>  0 pairs (X) / I8 = 5  =>  0 pairs (_)
B2,B7: 5.. / B2 = 5  =>  0 pairs (*) / B7 = 5  =>  0 pairs (X)
E6,E8: 5.. / E6 = 5  =>  0 pairs (*) / E8 = 5  =>  0 pairs (X)
F1,F7: 5.. / F1 = 5  =>  0 pairs (X) / F7 = 5  =>  0 pairs (_)
C2,C3: 6.. / C2 = 6  => 13 pairs (_) / C3 = 6  => 18 pairs (_)
E2,E3: 6.. / E2 = 6  => 18 pairs (_) / E3 = 6  => 13 pairs (_)
G9,I9: 6.. / G9 = 6  => 16 pairs (_) / I9 = 6  => 14 pairs (_)
C2,E2: 6.. / C2 = 6  => 13 pairs (_) / E2 = 6  => 18 pairs (_)
C3,E3: 6.. / C3 = 6  => 18 pairs (_) / E3 = 6  => 13 pairs (_)
B5,B6: 8.. / B5 = 8  => 13 pairs (_) / B6 = 8  => 17 pairs (_)
* DURATION: 0:00:58.359582  START: 17:20:52.844761  END: 17:21:51.204343 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B4,B6,B7,C9,D1,D5,E2,E3,E6,E8,F1,F7,I8)
* 843.9.7629..7.2...27.3.8.9.5.2.89.7.1.4.27..97.9..32..6.823.9474978.632.32.974...
* PAIR B2: 1,5 BLK 1
C2: 1,5,6                                # reduction candidate for 1,5
C2: 1,5                                  # 18 pairs
C3: 1,5,6                                # reduction candidate for 1,5
C3: 1,5                                  # 13 pairs
* PAIR B2: 1,5 ROW 2
G2: 1,5,4,8                              # reduction candidate for 1,5
G2: 1,5                                  # 16 pairs
H2: 1,5,3,8                              # reduction candidate for 1,5
H2: 1,5                                  # 13 pairs
I2: 1,5,3,4,8                            # reduction candidate for 1,5
I2: 1,5 => CTR
* 843.9.7629..74283.27.368.94562.894731346275897894532166.823594749781632.32.9746.8
I2: 3,4,8                                # 14 pairs
* PAIR D1: 1,5 COL D
D6: 1,5,4,6                              # reduction candidate for 1,5
D6: 4,6                                  # 15 pairs
D6: 1,5                                  # 14 pairs
* PAIR B4: 3,6 BLK 4
B5: 3,6,8                                # reduction candidate for 3,6
B5: 3,6                                  # 17 pairs
B5: 8                                    # 13 pairs
* PAIR B4: 3,6 ROW 4
I4: 3,6,1,4                              # reduction candidate for 3,6
I4: 1,4                                  # 19 pairs
I4: 3,6                                  # 17 pairs
* PAIR B6: 6,8 BLK 4
B5: 6,8,3                                # reduction candidate for 6,8
B5: 3                                    # 18 pairs
B5: 6,8                                  # 14 pairs
* PAIR B6: 6,8 ROW 6
I6: 6,8,1,4,5                            # reduction candidate for 6,8
I6: 1,4,5                                # 19 pairs
I6: 6,8                                  # 17 pairs
* PAIR D5: 5,6 BLK 5
D6: 5,6,1,4                              # reduction candidate for 5,6
D6: 5,6 => CTR
* 84319576291.7.2...27.3.81955.24896731.4.27..97.9.132.46.8231947497856321321974...
D6: 1,4                                  # 15 pairs
* PAIR D5: 5,6 ROW 5
G5: 5,6,8                                # reduction candidate for 5,6
G5: 8                                    # 21 pairs
G5: 5,6                                  # 17 pairs
* PAIR E6: 1,5 BLK 5
D6: 1,5,4,6                              # reduction candidate for 1,5
D6: 4,6                                  # 15 pairs
D6: 1,5                                  # 14 pairs
* PAIR E6: 1,5 ROW 6
H6: 1,5,8                                # reduction candidate for 1,5
H6: 1,5                                  # 16 pairs
I6: 1,5,4,6,8                            # reduction candidate for 1,5
I6: 1,5 => CTR
* 843.9.7629..7.28.327.3.8.9.532.89.761846275397694532816.8235947497816325325974618
I6: 4,6,8                                # 14 pairs
* PAIR C9: 1,5 ROW 9
G9: 1,5,6,8                              # reduction candidate for 1,5
G9: 1,5                                  # 19 pairs
H9: 1,5,8                                # reduction candidate for 1,5
H9: 1,5                                  # 17 pairs
I9: 1,5,6,8                              # reduction candidate for 1,5
I9: 1,5 => SOLVED
* 843591762956742138271368594562189473134627859789453216618235947497816325325974681
I9: 6,8                                  # 15 pairs
* PAIR C9: 1,5 COL C
C2: 1,5,6                                # reduction candidate for 1,5
C2: 1,5                                  # 18 pairs
C3: 1,5,6                                # reduction candidate for 1,5
C3: 1,5                                  # 13 pairs
* PAIR I8: 1,5 BLK 9
G9: 1,5,6,8                              # reduction candidate for 1,5
G9: 1,5                                  # 19 pairs
H9: 1,5,8                                # reduction candidate for 1,5
H9: 1,5                                  # 17 pairs
I9: 1,5,6,8                              # reduction candidate for 1,5
I9: 1,5 => SOLVED
* 843591762956742138271368594562189473134627859789453216618235947497816325325974681
I9: 6,8                                  # 15 pairs
* PAIR I8: 1,5 COL I
I2: 1,5,3,4,8                            # reduction candidate for 1,5
I2: 1,5 => CTR
* 843.9.7629..74283.27.368.94562.894731346275897894532166.823594749781632.32.9746.8
I2: 3,4,8                                # 14 pairs
I3: 1,5,4                                # reduction candidate for 1,5
I3: 1,5                                  # 16 pairs
I6: 1,5,4,6,8                            # reduction candidate for 1,5
I6: 1,5 => CTR
* 843.9.7629..7.28.327.3.8.9.532.89.761846275397694532816.8235947497816325325974618
I6: 4,6,8                                # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-426-base-pr-000.dot
* REASONING
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* DIS # D6: 5,6 => CTR => D6: 1,4
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* PRF # I9: 1,5 => SOL
* PRF # I9: 1,5 => SOL
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* CNT   7 HDP CHAINS /  40 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B4,B6,B7,C9,D1,D5,E2,E3,E6,E8,F1,F7,I8)
* 843.9.7629..7.2...27.3.8.9.5.2.89.7.1.4.27..97.9..32..6.823.9474978.632.32.974...
* PAIR B2: 1,5 BLK 1
C2: 1,5,6                                # reduction candidate for 1,5
C2: 1,5                                  # 18 pairs
C3: 1,5,6                                # reduction candidate for 1,5
C3: 1,5                                  # 13 pairs
* PAIR B2: 1,5 ROW 2
G2: 1,5,4,8                              # reduction candidate for 1,5
G2: 1,5                                  # 16 pairs
H2: 1,5,3,8                              # reduction candidate for 1,5
H2: 1,5                                  # 13 pairs
I2: 1,5,3,4,8                            # reduction candidate for 1,5
I2: 1,5 => CTR
* 843.9.7629..74283.27.368.94562.894731346275897894532166.823594749781632.32.9746.8
* PAIR RESTART
* PAIR B2: 1,5 BLK 1
C2: 1,5,6                                # reduction candidate for 1,5
C2: 1,5                                  # 18 pairs
C3: 1,5,6                                # reduction candidate for 1,5
C3: 1,5                                  # 14 pairs
* PAIR B2: 1,5 ROW 2
G2: 1,5,4,8                              # reduction candidate for 1,5
G2: 1,5                                  # 16 pairs
H2: 1,5,3,8                              # reduction candidate for 1,5
H2: 1,5                                  # 13 pairs
* PAIR D1: 1,5 COL D
D6: 1,5,4,6                              # reduction candidate for 1,5
D6: 4,6                                  # 15 pairs
D6: 1,5                                  # 14 pairs
* PAIR B4: 3,6 BLK 4
B5: 3,6,8                                # reduction candidate for 3,6
B5: 3,6                                  # 17 pairs
B5: 8                                    # 13 pairs
* PAIR B4: 3,6 ROW 4
I4: 3,6,1,4                              # reduction candidate for 3,6
I4: 1,4                                  # 19 pairs
I4: 3,6                                  # 17 pairs
* PAIR B6: 6,8 BLK 4
B5: 6,8,3                                # reduction candidate for 6,8
B5: 3                                    # 19 pairs
B5: 6,8                                  # 14 pairs
* PAIR B6: 6,8 ROW 6
I6: 6,8,1,4,5                            # reduction candidate for 6,8
I6: 1,4,5                                # 19 pairs
I6: 6,8                                  # 17 pairs
* PAIR D5: 5,6 BLK 5
D6: 5,6,1,4                              # reduction candidate for 5,6
D6: 5,6 => CTR
* 84319576291.7.2...27.3.81955.24896731.4.27..97.9.132.46.8231947497856321321974...
* PAIR D5: 5,6 ROW 5
G5: 5,6,8                                # reduction candidate for 5,6
G5: 8                                    # 22 pairs
G5: 5,6                                  # 18 pairs
* PAIR E6: 1,5 ROW 6
H6: 1,5,8                                # reduction candidate for 1,5
H6: 1,5                                  # 17 pairs
I6: 1,5,4,6,8                            # reduction candidate for 1,5
I6: 1,5 => CTR
* 843.9.7629..7.28.327.3.8.9.532.89.761846275397694532816.8235947497816325325974618
* RESTART
* PAIR E6: 1,5 ROW 6
H6: 1,5,8                                # reduction candidate for 1,5
H6: 8 => CTR
* 84359176295.7.2.3.27.3.859.5.2.89.731.4.27..97.9.5328.6.8235947497816325325974.1.
* PAIR RESTART
* PAIR C9: 1,5 ROW 9
G9: 1,5,6,8                              # reduction candidate for 1,5
G9: 1,5                                  # 17 pairs
H9: 1,5,8                                # reduction candidate for 1,5
H9: 1,5                                  # 23 pairs
I9: 1,5,6,8                              # reduction candidate for 1,5
I9: 1,5 => SOLVED
* 843591762956742138271368594562189473134627859789453216618235947497816325325974681
* DURATION: 0:00:32.574642  START: 17:22:32.023938  END: 17:23:04.598580 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-426-base-pr-001.dot
* REASONING
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* DIS I2: 3,4,8 # D6: 5,6 => CTR => D6: 1,4
* DIS I2: 3,4,8 + D6: 1,4 # I6: 1,5 => CTR => I6: 4,6,8
* DIS I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 # H6: 8 => CTR => H6: 1,5
* PRF I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 # I9: 1,5 => SOL
* STA I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 + I9: 1,5
* CNT   5 HDP CHAINS /  29 HYP OPENED

Header Info

Top 500 Minimum 17 426

solution: 843591762956742138271368594562189473134627859789453216618235947497816325325974681
info: 95181    FNBYK    S8.f     38718

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

Solution

position: 843591762956742138271368594562189473134627859789453216618235947497816325325974681 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 # C2: 1,5 => UNS
* INC # C3: 1,5 => UNS
* INC # G2: 1,5 => UNS
* INC # H2: 1,5 => UNS
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* INC # I2: 3,4,8 => UNS
* INC # D6: 1,5 => UNS
* INC # D6: 4,6 => UNS
* INC # B5: 3,6 => UNS
* INC # B5: 8 => UNS
* INC # I4: 3,6 => UNS
* INC # I4: 1,4 => UNS
* INC # B5: 6,8 => UNS
* INC # B5: 3 => UNS
* INC # I6: 6,8 => UNS
* INC # I6: 1,4,5 => UNS
* DIS # D6: 5,6 => CTR => D6: 1,4
* INC # D6: 1,4 => UNS
* INC # G5: 5,6 => UNS
* INC # G5: 8 => UNS
* INC # D6: 1,5 => UNS
* INC # D6: 4,6 => UNS
* INC # H6: 1,5 => UNS
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* INC # I6: 4,6,8 => UNS
* INC # G9: 1,5 => UNS
* INC # H9: 1,5 => UNS
* PRF # I9: 1,5 => SOL
* INC # I9: 6,8 => UNS
* INC # C2: 1,5 => UNS
* INC # C3: 1,5 => UNS
* INC # G9: 1,5 => UNS
* INC # H9: 1,5 => UNS
* PRF # I9: 1,5 => SOL
* INC # I9: 6,8 => UNS
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* INC # I2: 3,4,8 => UNS
* INC # I3: 1,5 => UNS
* DIS # I6: 1,5 => CTR => I6: 4,6,8
* INC # I6: 4,6,8 => UNS
* CNT  40 HDP CHAINS /  40 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C2: 1,5 => UNS
* INC # C3: 1,5 => UNS
* INC # G2: 1,5 => UNS
* INC # H2: 1,5 => UNS
* DIS # I2: 1,5 => CTR => I2: 3,4,8
* INC I2: 3,4,8 # C2: 1,5 => UNS
* INC I2: 3,4,8 # C3: 1,5 => UNS
* INC I2: 3,4,8 # G2: 1,5 => UNS
* INC I2: 3,4,8 # H2: 1,5 => UNS
* INC I2: 3,4,8 # D6: 1,5 => UNS
* INC I2: 3,4,8 # D6: 4,6 => UNS
* INC I2: 3,4,8 # B5: 3,6 => UNS
* INC I2: 3,4,8 # B5: 8 => UNS
* INC I2: 3,4,8 # I4: 3,6 => UNS
* INC I2: 3,4,8 # I4: 1,4 => UNS
* INC I2: 3,4,8 # B5: 6,8 => UNS
* INC I2: 3,4,8 # B5: 3 => UNS
* INC I2: 3,4,8 # I6: 6,8 => UNS
* INC I2: 3,4,8 # I6: 1,4,5 => UNS
* DIS I2: 3,4,8 # D6: 5,6 => CTR => D6: 1,4
* INC I2: 3,4,8 + D6: 1,4 # G5: 5,6 => UNS
* INC I2: 3,4,8 + D6: 1,4 # G5: 8 => UNS
* INC I2: 3,4,8 + D6: 1,4 # H6: 1,5 => UNS
* DIS I2: 3,4,8 + D6: 1,4 # I6: 1,5 => CTR => I6: 4,6,8
* INC I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 # H6: 1,5 => UNS
* DIS I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 # H6: 8 => CTR => H6: 1,5
* INC I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 # G9: 1,5 => UNS
* INC I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 # H9: 1,5 => UNS
* PRF I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 # I9: 1,5 => SOL
* STA I2: 3,4,8 + D6: 1,4 + I6: 4,6,8 + H6: 1,5 + I9: 1,5
* CNT  29 HDP CHAINS /  29 HYP OPENED