Analysis of xx-top500-495-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .......72.8.6......1.......4...97.........8..3........7.3....4....18.6.....5..... initial

Autosolve

position: 63.....72.876......1.7...8642..97...17....8..39....7..753...148.4.1836578615742.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C3: 2 => CTR => C3: 4,9
* DIS # G1: 4,9 => CTR => G1: 5
* DIS # I2: 5 => CTR => I2: 1,3
* PRF # H4: 1,3 => SOL
* DIS # C6: 5,6 => CTR => C6: 8
* DIS # E5: 5,6 => CTR => E5: 2,4
* PRF # I4: 3,5 => SOL
* DIS # I5: 3,5 => CTR => I5: 4,9
* DIS # G2: 3,5 => CTR => G2: 4,9
* DIS # G3: 3,5 => CTR => G3: 4,9
* PRF # H5: 2,6 => SOL
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* DIS # I5: 4,5 => CTR => I5: 3,9
* PRF # E6: 4,5 => SOL
* DIS # E6: 1,2,6 => CTR => E6: 4,5
* DIS # C3: 2,9 => CTR => C3: 4
* PRF # C3: 4 => SOL
* PRF # F7: 2,9 => SOL
* DIS # F7: 6 => CTR => F7: 2,9
* PRF # F7: 2,6 => SOL
* DIS # F7: 9 => CTR => F7: 2,6
* DIS # E5: 2,6 => CTR => E5: 4,5
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* PRF # H5: 2,6 => SOL
* DIS # I5: 4,5 => CTR => I5: 3,9
* CNT  27 HDP CHAINS /  47 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 # C3: 2 => CTR => C3: 4,9
* DIS C3: 4,9 # G1: 4,9 => CTR => G1: 5
* DIS C3: 4,9 + G1: 5 # E5: 5,6 => CTR => E5: 2,4
* PRF C3: 4,9 + G1: 5 + E5: 2,4 # F7: 2,9 => SOL
* STA C3: 4,9 + G1: 5 + E5: 2,4 + F7: 2,9
* CNT   4 HDP CHAINS /   6 HYP OPENED

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

Details

Positions

.......72.8.6......1.......4...97.........8..3........7.3....4....18.6.....5..... initial
63.....72.876......1.7...8642..97...17....8..39....7..753...148.4.1836578615742.. autosolve
639418572587629431214735986426897315175346829398251764753962148942183657861574293 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
C1: 4,9
F1: 1,8
H2: 1,3
C5: 5,6
D4: 3,8
F6: 1,8
G4: 3,5
H6: 2,6
I6: 4,5
A8: 2,9
C8: 2,9
D7: 2,9
E7: 2,6
H9: 3,9
I9: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E1,F1: 1.. / E1 = 1  => 19 pairs (_) / F1 = 1  =>  0 pairs (X)
H2,I2: 1.. / H2 = 1  => 16 pairs (_) / I2 = 1  =>  0 pairs (*)
E6,F6: 1.. / E6 = 1  =>  0 pairs (X) / F6 = 1  => 19 pairs (_)
H4,I4: 1.. / H4 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
E1,E6: 1.. / E1 = 1  => 19 pairs (_) / E6 = 1  =>  0 pairs (X)
F1,F6: 1.. / F1 = 1  =>  0 pairs (X) / F6 = 1  => 19 pairs (_)
H2,H4: 1.. / H2 = 1  => 16 pairs (_) / H4 = 1  =>  0 pairs (*)
I2,I4: 1.. / I2 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
H5,H6: 2.. / H5 = 2  =>  0 pairs (*) / H6 = 2  =>  0 pairs (X)
A8,C8: 2.. / A8 = 2  =>  0 pairs (X) / C8 = 2  => 16 pairs (_)
C3,C8: 2.. / C3 = 2  =>  0 pairs (X) / C8 = 2  => 16 pairs (_)
E2,E3: 3.. / E2 = 3  =>  0 pairs (X) / E3 = 3  => 15 pairs (_)
D4,D5: 3.. / D4 = 3  =>  0 pairs (X) / D5 = 3  => 19 pairs (_)
H9,I9: 3.. / H9 = 3  => 14 pairs (_) / I9 = 3  => 16 pairs (_)
E3,G3: 3.. / E3 = 3  => 15 pairs (_) / G3 = 3  =>  0 pairs (X)
C1,C3: 4.. / C1 = 4  =>  0 pairs (X) / C3 = 4  =>  0 pairs (_)
I5,I6: 4.. / I5 = 4  =>  0 pairs (X) / I6 = 4  => 15 pairs (_)
E2,G2: 4.. / E2 = 4  =>  0 pairs (X) / G2 = 4  => 16 pairs (_)
A2,A3: 5.. / A2 = 5  => 23 pairs (_) / A3 = 5  => 17 pairs (_)
E1,G1: 5.. / E1 = 5  =>  0 pairs (X) / G1 = 5  => 19 pairs (_)
E7,F7: 6.. / E7 = 6  =>  0 pairs (*) / F7 = 6  =>  0 pairs (X)
C4,H4: 6.. / C4 = 6  =>  0 pairs (*) / H4 = 6  =>  0 pairs (X)
F5,F7: 6.. / F5 = 6  =>  0 pairs (*) / F7 = 6  =>  0 pairs (X)
D1,F1: 8.. / D1 = 8  =>  0 pairs (X) / F1 = 8  => 19 pairs (_)
C4,C6: 8.. / C4 = 8  =>  0 pairs (X) / C6 = 8  => 19 pairs (_)
C4,D4: 8.. / C4 = 8  =>  0 pairs (X) / D4 = 8  => 19 pairs (_)
F1,F6: 8.. / F1 = 8  => 19 pairs (_) / F6 = 8  =>  0 pairs (X)
H5,I5: 9.. / H5 = 9  => 14 pairs (_) / I5 = 9  => 16 pairs (_)
A8,C8: 9.. / A8 = 9  => 16 pairs (_) / C8 = 9  =>  0 pairs (X)
D7,F7: 9.. / D7 = 9  =>  0 pairs (*) / F7 = 9  =>  0 pairs (X)
H9,I9: 9.. / H9 = 9  => 16 pairs (_) / I9 = 9  => 14 pairs (_)
D1,D7: 9.. / D1 = 9  =>  0 pairs (X) / D7 = 9  =>  0 pairs (_)
H5,H9: 9.. / H5 = 9  => 14 pairs (_) / H9 = 9  => 16 pairs (_)
I5,I9: 9.. / I5 = 9  => 16 pairs (_) / I9 = 9  => 14 pairs (_)
* DURATION: 0:00:58.932219  START: 19:35:08.389572  END: 19:36:07.321791 2017-05-04
* CP COUNT: (34)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,C1,C5,C8,D4,D7,E7,F1,F6,G4,H2,H6,H9,I6,I9)
* 63.....72.876......1.7...8642..97...17....8..39....7..753...148.4.1836578615742..
* PAIR C1: 4,9 BLK 1
C3: 4,9,2                                # reduction candidate for 4,9
C3: 2 => CTR
* 6349.85725876.2913912735486425897361176.2.8..39....72.7532691482491836578615742..
C3: 4,9                                  # 16 pairs
* PAIR C1: 4,9 ROW 1
D1: 4,9,8                                # reduction candidate for 4,9
D1: 4,9                                  # 19 pairs
G1: 4,9,5                                # reduction candidate for 4,9
G1: 4,9 => CTR
* 63.851.72.876......1.7...86428397561176..58..39..187..753..6148.4.1836578615742..
G1: 5                                    # 19 pairs
* PAIR H2: 1,3 BLK 3
I2: 1,3,5                                # reduction candidate for 1,3
I2: 5 => CTR
* 63..51.72.876...1551.7...86428397561176..58..395...7.4753..6148.4.1836578615742..
I2: 1,3                                  # 19 pairs
* PAIR H2: 1,3 COL H
H4: 1,3,6                                # reduction candidate for 1,3
H4: 1,3 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
H4: 6                                    # 17 pairs
* PAIR C5: 5,6 BLK 4
C4: 5,6,8                                # reduction candidate for 5,6
C4: 5,6                                  # 19 pairs
C6: 5,6,8                                # reduction candidate for 5,6
C6: 5,6 => CTR
* 63..51.72.876...1551.7...8642839756117...58..3958..724753...148.4.1836578615742..
C6: 8                                    # 19 pairs
* PAIR C5: 5,6 ROW 5
E5: 5,6,2,4                              # reduction candidate for 5,6
E5: 5,6 => CTR
* 63.....72.876...1..1.7...8642..97.6117...28..39....72.75326.148.4.1836578615742..
E5: 2,4                                  # 24 pairs
F5: 5,6,2                                # reduction candidate for 5,6
F5: 5,6                                  # 24 pairs
* PAIR G4: 3,5 BLK 6
I4: 3,5,1                                # reduction candidate for 3,5
I4: 3,5 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
I4: 1                                    # 16 pairs
I5: 3,5,4,9                              # reduction candidate for 3,5
I5: 3,5 => CTR
* 63..18572.876...13.1.73..8642..97.6117....89.39.8.1724753...148.4.183657861574239
I5: 4,9                                  # 16 pairs
* PAIR G4: 3,5 COL G
G2: 3,5,4,9                              # reduction candidate for 3,5
G2: 3,5 => CTR
* 63.851.72.8764.....1.73..8642..97...17....8..39....7..753...148.4.1836578615742..
G2: 4,9                                  # 16 pairs
G3: 3,5,4,9                              # reduction candidate for 3,5
G3: 3,5 => CTR
* 63.851.72.876......1.7...8642839756117...58..395...7..753...148.4.1836578615742..
G3: 4,9                                  # 16 pairs
* PAIR H6: 2,6 BLK 6
H5: 2,6,3,9                              # reduction candidate for 2,6
H5: 2,6 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
H5: 3,9                                  # 17 pairs
* PAIR H6: 2,6 ROW 6
E6: 2,6,1,4,5                            # reduction candidate for 2,6
E6: 2,6 => CTR
* 63..18572.876......1.73..864258973611763..8.43984617257532..148.4.1836578615742..
E6: 1,4,5 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
* PAIR I6: 4,5 BLK 6
I5: 4,5,3,9                              # reduction candidate for 4,5
I5: 4,5 => CTR
* 63.9.8.72.876...13.1.73..8642.89736117.3.689.39....72.753269148.4.183657861574239
I5: 3,9                                  # 19 pairs
* PAIR I6: 4,5 ROW 6
E6: 4,5,1,2,6                            # reduction candidate for 4,5
E6: 4,5 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
E6: 1,2,6 => CTR
* 63..18572.876......1.7...8642..97361176...8..39..6172.753.26148.4.1836578615742..
* PAIR A8: 2,9 COL A
A2: 2,9,5                                # reduction candidate for 2,9
A2: 2,9                                  # 17 pairs
A3: 2,9,5                                # reduction candidate for 2,9
A3: 2,9                                  # 23 pairs
* PAIR C8: 2,9 COL C
C3: 2,9,4                                # reduction candidate for 2,9
C3: 2,9 => CTR
* 6349.8572.876..913.1.73.486425897361176...8..39....72.753269148.4.1836578615742..
C3: 4 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
* PAIR D7: 2,9 BLK 8
F7: 2,9,6                                # reduction candidate for 2,9
F7: 2,9 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
F7: 6 => CTR
* 63.418572.876..4...147..98642..9736.176.458..39..61724753926148.4.1836578615742..
* PAIR E7: 2,6 BLK 8
F7: 2,6,9                                # reduction candidate for 2,6
F7: 2,6 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
F7: 9 => CTR
* 634918572.876......1.7...8642..973.5175..68..39..517.4753269148.4.1836578615742..
* PAIR E7: 2,6 COL E
E5: 2,6,4,5                              # reduction candidate for 2,6
E5: 2,6 => CTR
* 63.9.8.72.876...1..1.7...8642839756117542.8..396...72.753269148.4.1836578615742..
E5: 4,5                                  # 16 pairs
E6: 2,6,1,4,5                            # reduction candidate for 2,6
E6: 2,6 => CTR
* 63..18572.876......1.73..864258973611763..8.43984617257532..148.4.1836578615742..
E6: 1,4,5 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
* PAIR H9: 3,9 COL H
H5: 3,9,2,6                              # reduction candidate for 3,9
H5: 2,6 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
H5: 3,9                                  # 17 pairs
* PAIR I9: 3,9 COL I
I5: 3,9,4,5                              # reduction candidate for 3,9
I5: 4,5 => CTR
* 63.9.8.72.876...13.1.73..8642.89736117.3.689.39....72.753269148.4.183657861574239
I5: 3,9                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-495-base-pr-000.dot
* REASONING
* DIS # C3: 2 => CTR => C3: 4,9
* DIS # G1: 4,9 => CTR => G1: 5
* DIS # I2: 5 => CTR => I2: 1,3
* PRF # H4: 1,3 => SOL
* DIS # C6: 5,6 => CTR => C6: 8
* DIS # E5: 5,6 => CTR => E5: 2,4
* PRF # I4: 3,5 => SOL
* DIS # I5: 3,5 => CTR => I5: 4,9
* DIS # G2: 3,5 => CTR => G2: 4,9
* DIS # G3: 3,5 => CTR => G3: 4,9
* PRF # H5: 2,6 => SOL
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* DIS # I5: 4,5 => CTR => I5: 3,9
* PRF # E6: 4,5 => SOL
* DIS # E6: 1,2,6 => CTR => E6: 4,5
* DIS # C3: 2,9 => CTR => C3: 4
* PRF # C3: 4 => SOL
* PRF # F7: 2,9 => SOL
* DIS # F7: 6 => CTR => F7: 2,9
* PRF # F7: 2,6 => SOL
* DIS # F7: 9 => CTR => F7: 2,6
* DIS # E5: 2,6 => CTR => E5: 4,5
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* PRF # H5: 2,6 => SOL
* DIS # I5: 4,5 => CTR => I5: 3,9
* CNT  27 HDP CHAINS /  47 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A8,C1,C5,C8,D4,D7,E7,F1,F6,G4,H2,H6,H9,I6,I9)
* 63.....72.876......1.7...8642..97...17....8..39....7..753...148.4.1836578615742..
* PAIR C1: 4,9 BLK 1
C3: 4,9,2                                # reduction candidate for 4,9
C3: 2 => CTR
* 6349.85725876.2913912735486425897361176.2.8..39....72.7532691482491836578615742..
* PAIR C1: 4,9 ROW 1
D1: 4,9,8                                # reduction candidate for 4,9
D1: 4,9                                  # 21 pairs
G1: 4,9,5                                # reduction candidate for 4,9
G1: 4,9 => CTR
* 63.851.72.876......1.7...86428397561176..58..39..187..753..61489421836578615742..
* RESTART
* PAIR RESTART
* PAIR C5: 5,6 ROW 5
E5: 5,6,2,4                              # reduction candidate for 5,6
E5: 5,6 => CTR
* 63..18572.876....3.1.73..864258973611763528943984617.5753...1489421836578615742.9
* RESTART
* PAIR RESTART
* PAIR D7: 2,9 BLK 8
F7: 2,9,6                                # reduction candidate for 2,9
F7: 2,9 => SOLVED
* 639418572587629431214735986426897315175346829398251764753962148942183657861574293
* DURATION: 0:00:08.947809  START: 19:36:58.672478  END: 19:37:07.620287 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-495-base-pr-001.dot
* REASONING
* DIS # C3: 2 => CTR => C3: 4,9
* DIS C3: 4,9 # G1: 4,9 => CTR => G1: 5
* DIS C3: 4,9 + G1: 5 # E5: 5,6 => CTR => E5: 2,4
* PRF C3: 4,9 + G1: 5 + E5: 2,4 # F7: 2,9 => SOL
* STA C3: 4,9 + G1: 5 + E5: 2,4 + F7: 2,9
* CNT   4 HDP CHAINS /   6 HYP OPENED

Header Info

Top 500 Minimum 17 495

solution: 639418572587629431214735986426897315175346829398251764753962148942183657861574293
info: 96454    FNBHYK   S8.f     626

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

Solution

position: 639418572587629431214735986426897315175346829398251764753962148942183657861574293 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 # C3: 4,9 => UNS
* DIS # C3: 2 => CTR => C3: 4,9
* INC # D1: 4,9 => UNS
* DIS # G1: 4,9 => CTR => G1: 5
* INC # G1: 5 => UNS
* INC # I2: 1,3 => UNS
* DIS # I2: 5 => CTR => I2: 1,3
* PRF # H4: 1,3 => SOL
* INC # H4: 6 => UNS
* INC # C4: 5,6 => UNS
* DIS # C6: 5,6 => CTR => C6: 8
* INC # C6: 8 => UNS
* DIS # E5: 5,6 => CTR => E5: 2,4
* INC # E5: 2,4 => UNS
* INC # F5: 5,6 => UNS
* PRF # I4: 3,5 => SOL
* INC # I4: 1 => UNS
* DIS # I5: 3,5 => CTR => I5: 4,9
* INC # I5: 4,9 => UNS
* DIS # G2: 3,5 => CTR => G2: 4,9
* INC # G2: 4,9 => UNS
* DIS # G3: 3,5 => CTR => G3: 4,9
* INC # G3: 4,9 => UNS
* PRF # H5: 2,6 => SOL
* INC # H5: 3,9 => UNS
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* DIS # I5: 4,5 => CTR => I5: 3,9
* INC # I5: 3,9 => UNS
* PRF # E6: 4,5 => SOL
* DIS # E6: 1,2,6 => CTR => E6: 4,5
* INC # A2: 2,9 => UNS
* INC # A3: 2,9 => UNS
* DIS # C3: 2,9 => CTR => C3: 4
* PRF # C3: 4 => SOL
* PRF # F7: 2,9 => SOL
* DIS # F7: 6 => CTR => F7: 2,9
* PRF # F7: 2,6 => SOL
* DIS # F7: 9 => CTR => F7: 2,6
* DIS # E5: 2,6 => CTR => E5: 4,5
* INC # E5: 4,5 => UNS
* DIS # E6: 2,6 => CTR => E6: 1,4,5
* PRF # E6: 1,4,5 => SOL
* INC # H5: 3,9 => UNS
* PRF # H5: 2,6 => SOL
* INC # I5: 3,9 => UNS
* DIS # I5: 4,5 => CTR => I5: 3,9
* CNT  47 HDP CHAINS /  47 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C3: 4,9 => UNS
* DIS # C3: 2 => CTR => C3: 4,9
* INC C3: 4,9 # D1: 4,9 => UNS
* DIS C3: 4,9 # G1: 4,9 => CTR => G1: 5
* DIS C3: 4,9 + G1: 5 # E5: 5,6 => CTR => E5: 2,4
* PRF C3: 4,9 + G1: 5 + E5: 2,4 # F7: 2,9 => SOL
* STA C3: 4,9 + G1: 5 + E5: 2,4 + F7: 2,9
* CNT   6 HDP CHAINS /   6 HYP OPENED