Analysis of xx-top500-071-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .5..4.3..2......7.............6.2.8..31.........7.....6..2...........4.3....1.5.. initial

Autosolve

position: 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.51....4.39..31456. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B3: 8 => CTR => B3: 6,7
* DIS # B3: 6,8 => CTR => B3: 7
* PRF # B3: 7 => SOL
* DIS # E2: 6,8 => CTR => E2: 9
* PRF # E2: 9 => SOL
* PRF # G2: 6,8 => SOL
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # I1: 8,9 => CTR => I1: 2
* PRF # I1: 2 => SOL
* PRF # F3: 6,7 => SOL
* DIS # F3: 8 => CTR => F3: 6,7
* PRF # I2: 1,5 => SOL
* PRF # I3: 8 => SOL
* PRF # I1: 2,9 => SOL
* DIS # I1: 8 => CTR => I1: 2,9
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* DIS # C9: 2,7 => CTR => C9: 8
* DIS # I9: 8 => CTR => I9: 2,7
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* DIS # I7: 7,8 => CTR => I7: 9
* PRF # I7: 9 => SOL
* PRF # I9: 7,8 => SOL
* DIS # I9: 2 => CTR => I9: 7,8
* PRF # E7: 7,8 => SOL
* DIS # E7: 9 => CTR => E7: 7,8
* CNT  36 HDP CHAINS /  45 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: 8 => CTR => B3: 6,7
* DIS B3: 6,7 # I1: 8,9 => CTR => I1: 2
* PRF B3: 6,7 + I1: 2 => SOL
* STA B3: 6,7 + I1: 2
* CNT   3 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

.5..4.3..2......7.............6.2.8..31.........7.....6..2...........4.3....1.5.. initial
15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.51....4.39..31456. autosolve
156847392284193675379526148495632781731489256862751934643275819517968423928314567 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
C1: 6,7
B2: 6,8
D1: 8,9
F1: 6,7
D2: 1,5
D3: 1,5
H1: 2,9
B6: 2,6
C6: 2,6
E5: 8,9
F5: 8,9
G4: 1,7
I4: 1,7
B9: 2,7
D8: 8,9
G7: 7,8
H8: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D2,D3: 1.. / D2 = 1  =>  0 pairs (*) / D3 = 1  =>  0 pairs (X)
G4,I4: 1.. / G4 = 1  =>  0 pairs (X) / I4 = 1  => 21 pairs (_)
H1,I1: 2.. / H1 = 2  =>  0 pairs (X) / I1 = 2  =>  0 pairs (_)
B6,C6: 2.. / B6 = 2  =>  0 pairs (X) / C6 = 2  =>  0 pairs (_)
H8,I9: 2.. / H8 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
C8,H8: 2.. / C8 = 2  =>  0 pairs (X) / H8 = 2  =>  0 pairs (_)
B6,B9: 2.. / B6 = 2  =>  0 pairs (X) / B9 = 2  =>  0 pairs (_)
H1,H8: 2.. / H1 = 2  =>  0 pairs (X) / H8 = 2  =>  0 pairs (_)
I1,I9: 2.. / I1 = 2  =>  0 pairs (*) / I9 = 2  =>  0 pairs (X)
D2,D3: 5.. / D2 = 5  => 16 pairs (_) / D3 = 5  =>  0 pairs (*)
I2,I3: 5.. / I2 = 5  =>  0 pairs (*) / I3 = 5  =>  0 pairs (X)
D2,I2: 5.. / D2 = 5  => 16 pairs (_) / I2 = 5  =>  0 pairs (*)
D3,I3: 5.. / D3 = 5  =>  0 pairs (*) / I3 = 5  =>  0 pairs (X)
G2,G3: 6.. / G2 = 6  =>  0 pairs (*) / G3 = 6  =>  0 pairs (X)
B6,C6: 6.. / B6 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
E8,F8: 6.. / E8 = 6  =>  0 pairs (*) / F8 = 6  =>  0 pairs (X)
C1,F1: 6.. / C1 = 6  =>  0 pairs (*) / F1 = 6  =>  0 pairs (X)
C1,C6: 6.. / C1 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
E2,E8: 6.. / E2 = 6  =>  0 pairs (X) / E8 = 6  =>  0 pairs (_)
C1,B3: 7.. / C1 = 7  =>  0 pairs (X) / B3 = 7  =>  0 pairs (_)
F1,F3: 7.. / F1 = 7  =>  0 pairs (*) / F3 = 7  =>  0 pairs (X)
G4,I4: 7.. / G4 = 7  => 21 pairs (_) / I4 = 7  =>  0 pairs (X)
E7,E8: 7.. / E7 = 7  =>  0 pairs (*) / E8 = 7  =>  0 pairs (X)
C1,F1: 7.. / C1 = 7  =>  0 pairs (X) / F1 = 7  =>  0 pairs (_)
B3,F3: 7.. / B3 = 7  =>  0 pairs (*) / F3 = 7  =>  0 pairs (X)
C8,E8: 7.. / C8 = 7  =>  0 pairs (*) / E8 = 7  =>  0 pairs (X)
B3,B9: 7.. / B3 = 7  =>  0 pairs (*) / B9 = 7  =>  0 pairs (X)
G4,G7: 7.. / G4 = 7  => 21 pairs (_) / G7 = 7  =>  0 pairs (X)
B2,B3: 8.. / B2 = 8  => 19 pairs (_) / B3 = 8  =>  0 pairs (X)
E5,F5: 8.. / E5 = 8  => 20 pairs (_) / F5 = 8  =>  0 pairs (X)
C8,C9: 8.. / C8 = 8  =>  0 pairs (X) / C9 = 8  => 20 pairs (_)
D1,I1: 8.. / D1 = 8  =>  0 pairs (*) / I1 = 8  =>  0 pairs (X)
C9,I9: 8.. / C9 = 8  => 20 pairs (_) / I9 = 8  =>  0 pairs (X)
D1,D8: 8.. / D1 = 8  =>  0 pairs (*) / D8 = 8  =>  0 pairs (X)
D1,E2: 9.. / D1 = 9  =>  0 pairs (X) / E2 = 9  =>  0 pairs (_)
E5,F5: 9.. / E5 = 9  =>  0 pairs (X) / F5 = 9  => 20 pairs (_)
I7,H8: 9.. / I7 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
E2,I2: 9.. / E2 = 9  =>  0 pairs (*) / I2 = 9  =>  0 pairs (X)
E7,I7: 9.. / E7 = 9  =>  0 pairs (X) / I7 = 9  =>  0 pairs (_)
D1,D8: 9.. / D1 = 9  =>  0 pairs (X) / D8 = 9  =>  0 pairs (_)
F5,F8: 9.. / F5 = 9  => 20 pairs (_) / F8 = 9  =>  0 pairs (X)
H1,H8: 9.. / H1 = 9  =>  0 pairs (*) / H8 = 9  =>  0 pairs (X)
* DURATION: 0:01:32.678191  START: 05:06:38.529858  END: 05:08:11.208049 2017-05-04
* CP COUNT: (42)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B6,B9,C1,C6,D1,D2,D3,D8,E5,F1,F5,G4,G7,H1,H8,I4)
* 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.51....4.39..31456.
* PAIR C1: 6,7 BLK 1
B3: 6,7,8                                # reduction candidate for 6,7
B3: 8 => CTR
* 157.463..264..3.7.389.2764.495632.8.7314..2568267519346432.5.1.51....4.39..31456.
B3: 6,7                                  # 19 pairs
* PAIR B2: 6,8 BLK 1
B3: 6,8,7                                # reduction candidate for 6,8
B3: 6,8 => CTR
* 157.463..2.4..3.7.3.9.27.4.495632.8.7314..2568.67519346432.5.1.51....4.39..31456.
B3: 7 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
* PAIR B2: 6,8 ROW 2
E2: 6,8,9                                # reduction candidate for 6,8
E2: 6,8 => CTR
* 15.94.3282.4..3.793.9.2..45495632.817314..2568..75193464329581751287649397831456.
E2: 9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
G2: 6,8,1                                # reduction candidate for 6,8
G2: 6,8 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
G2: 1                                    # 19 pairs
* PAIR D1: 8,9 BLK 2
E2: 8,9,6                                # reduction candidate for 8,9
E2: 8,9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
E2: 6 => CTR
* 15.94.328284.631793.912864549563278173148925686275193464329581751.87.4.39..31456.
* PAIR D1: 8,9 ROW 1
I1: 8,9,2                                # reduction candidate for 8,9
I1: 8,9 => CTR
* 15..4.32.2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.512.7649397831456.
I1: 2 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
* PAIR F1: 6,7 BLK 2
F3: 6,7,8                                # reduction candidate for 6,7
F3: 6,7 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
F3: 8 => CTR
* 15..473..2.4.63.79379.28645495632.81731489256862751934643295.1.51.8..4.39..31456.
* PAIR D2: 1,5 ROW 2
I2: 1,5,8,9                              # reduction candidate for 1,5
I2: 1,5 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
I2: 8,9                                  # 19 pairs
* PAIR D3: 1,5 ROW 3
I3: 1,5,8                                # reduction candidate for 1,5
I3: 8 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
I3: 1,5                                  # 19 pairs
* PAIR H1: 2,9 BLK 3
I1: 2,9,8                                # reduction candidate for 2,9
I1: 2,9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
I1: 8 => CTR
* 15..4.3282.4..3.793.9.2..45495632.817314..2568..75193464329581751287649397831456.
* PAIR E5: 8,9 COL E
E2: 8,9,6                                # reduction candidate for 8,9
E2: 8,9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
E2: 6 => CTR
* 15.94.328284.631793.912864549563278173148925686275193464329581751.87.4.39..31456.
E7: 8,9,7                                # reduction candidate for 8,9
E7: 8,9 => CTR
* 156.473..284.6317937912864549563278173148925686275193464329581.51..764.39..31456.
E7: 7 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
E8: 8,9,6,7                              # reduction candidate for 8,9
E8: 8,9 => CTR
* 15..4.3..2.4.63.793.9.2.645495632.817314..2568627519346432.5.1.51....4.39..31456.
E8: 6,7                                  # 18 pairs
* PAIR F5: 8,9 COL F
F8: 8,9,6                                # reduction candidate for 8,9
F8: 8,9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
F8: 6 => CTR
* 156.473..284.6317937912864549563278173148925686275193464329581.51...64.39..31456.
* PAIR B9: 2,7 BLK 7
C8: 2,7,8                                # reduction candidate for 2,7
C8: 2,7                                  # 20 pairs
C9: 2,7,8                                # reduction candidate for 2,7
C9: 2,7 => CTR
* 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.5189764239..314568
C9: 8                                    # 20 pairs
* PAIR B9: 2,7 ROW 9
I9: 2,7,8                                # reduction candidate for 2,7
I9: 8 => CTR
* 15.84.3922.4.93.7.3.9.2..4.495632.8.7314892568..751934643275.1.51....4239..314568
I9: 2,7                                  # 20 pairs
* PAIR D8: 8,9 BLK 8
E7: 8,9,7                                # reduction candidate for 8,9
E7: 8,9 => CTR
* 156.473..284.6317937912864549563278173148925686275193464329581.51..764.39..31456.
E7: 7 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
E8: 8,9,6,7                              # reduction candidate for 8,9
E8: 8,9 => CTR
* 15..4.3..2.4.63.793.9.2.645495632.817314..2568627519346432.5.1.51....4.39..31456.
E8: 6,7                                  # 18 pairs
F8: 8,9,6                                # reduction candidate for 8,9
F8: 8,9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
F8: 6 => CTR
* 156.473..284.6317937912864549563278173148925686275193464329581.51...64.39..31456.
* PAIR G7: 7,8 BLK 9
I7: 7,8,9                                # reduction candidate for 7,8
I7: 7,8 => CTR
* 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..751934643295.1.51.8764939.8314562
I7: 9 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
I9: 7,8,2                                # reduction candidate for 7,8
I9: 7,8 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
I9: 2 => CTR
* 15..4.32.2.4..3.7.3.9.2..4.495632.8.7314..2568267519346432.5.1.512.76493978314562
* PAIR G7: 7,8 ROW 7
E7: 7,8,9                                # reduction candidate for 7,8
E7: 7,8 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
E7: 9 => CTR
* 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..751934643295.1.51.8764939.8314562
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-071-base-pr-000.dot
* REASONING
* DIS # B3: 8 => CTR => B3: 6,7
* DIS # B3: 6,8 => CTR => B3: 7
* PRF # B3: 7 => SOL
* DIS # E2: 6,8 => CTR => E2: 9
* PRF # E2: 9 => SOL
* PRF # G2: 6,8 => SOL
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # I1: 8,9 => CTR => I1: 2
* PRF # I1: 2 => SOL
* PRF # F3: 6,7 => SOL
* DIS # F3: 8 => CTR => F3: 6,7
* PRF # I2: 1,5 => SOL
* PRF # I3: 8 => SOL
* PRF # I1: 2,9 => SOL
* DIS # I1: 8 => CTR => I1: 2,9
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* DIS # C9: 2,7 => CTR => C9: 8
* DIS # I9: 8 => CTR => I9: 2,7
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* DIS # I7: 7,8 => CTR => I7: 9
* PRF # I7: 9 => SOL
* PRF # I9: 7,8 => SOL
* DIS # I9: 2 => CTR => I9: 7,8
* PRF # E7: 7,8 => SOL
* DIS # E7: 9 => CTR => E7: 7,8
* CNT  36 HDP CHAINS /  45 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B2,B6,B9,C1,C6,D1,D2,D3,D8,E5,F1,F5,G4,G7,H1,H8,I4)
* 15..4.3..2.4..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.51....4.39..31456.
* PAIR C1: 6,7 BLK 1
B3: 6,7,8                                # reduction candidate for 6,7
B3: 8 => CTR
* 157.463..264..3.7.389.2764.495632.8.7314..2568267519346432.5.1.51....4.39..31456.
* PAIR D1: 8,9 ROW 1
I1: 8,9,2                                # reduction candidate for 8,9
I1: 8,9 => CTR
* 15..4.32.284..3.7.3.9.2..4.495632.8.7314..2568..7519346432.5.1.512.7649397831456.
I1: 2 => SOLVED
* 156847392284193675379526148495632781731489256862751934643275819517968423928314567
* DURATION: 0:00:06.304868  START: 05:09:18.036926  END: 05:09:24.341794 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-071-base-pr-001.dot
* REASONING
* DIS # B3: 8 => CTR => B3: 6,7
* DIS B3: 6,7 # I1: 8,9 => CTR => I1: 2
* PRF B3: 6,7 + I1: 2 => SOL
* STA B3: 6,7 + I1: 2
* CNT   3 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 071

solution: 156847392284193675379526148495632781731489256862751934643275819517968423928314567
info: 1460     FNBTHWY  S8.f     20013

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

Solution

position: 156847392284193675379526148495632781731489256862751934643275819517968423928314567 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 # B3: 6,7 => UNS
* DIS # B3: 8 => CTR => B3: 6,7
* DIS # B3: 6,8 => CTR => B3: 7
* PRF # B3: 7 => SOL
* DIS # E2: 6,8 => CTR => E2: 9
* PRF # E2: 9 => SOL
* PRF # G2: 6,8 => SOL
* INC # G2: 1 => UNS
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # I1: 8,9 => CTR => I1: 2
* PRF # I1: 2 => SOL
* PRF # F3: 6,7 => SOL
* DIS # F3: 8 => CTR => F3: 6,7
* PRF # I2: 1,5 => SOL
* INC # I2: 8,9 => UNS
* INC # I3: 1,5 => UNS
* PRF # I3: 8 => SOL
* PRF # I1: 2,9 => SOL
* DIS # I1: 8 => CTR => I1: 2,9
* PRF # E2: 8,9 => SOL
* DIS # E2: 6 => CTR => E2: 8,9
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* INC # E8: 6,7 => UNS
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* INC # C8: 2,7 => UNS
* DIS # C9: 2,7 => CTR => C9: 8
* INC # C9: 8 => UNS
* INC # I9: 2,7 => UNS
* DIS # I9: 8 => CTR => I9: 2,7
* DIS # E7: 8,9 => CTR => E7: 7
* PRF # E7: 7 => SOL
* DIS # E8: 8,9 => CTR => E8: 6,7
* INC # E8: 6,7 => UNS
* PRF # F8: 8,9 => SOL
* DIS # F8: 6 => CTR => F8: 8,9
* DIS # I7: 7,8 => CTR => I7: 9
* PRF # I7: 9 => SOL
* PRF # I9: 7,8 => SOL
* DIS # I9: 2 => CTR => I9: 7,8
* PRF # E7: 7,8 => SOL
* DIS # E7: 9 => CTR => E7: 7,8
* CNT  45 HDP CHAINS /  45 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 6,7 => UNS
* DIS # B3: 8 => CTR => B3: 6,7
* DIS B3: 6,7 # I1: 8,9 => CTR => I1: 2
* PRF B3: 6,7 + I1: 2 => SOL
* STA B3: 6,7 + I1: 2
* CNT   4 HDP CHAINS /   3 HYP OPENED