Analysis of xx-top500-499-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6.71............48.............4..2.....85...1...........3.87...45...6...2....... initial

Autosolve

position: 6871.42.5...567.48...8.2.......41.2.....85...1...73...9..328754.457196.272.456... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # A5: 2,3 => SOL
* DIS # A5: 4 => CTR => A5: 2,3
* DIS # B3: 3,9 => CTR => B3: 1,5
* DIS # C3: 3,9 => CTR => C3: 1,4
* DIS # H5: 3,9 => CTR => H5: 1,6,7
* DIS # H9: 3,9 => CTR => H9: 1,8
* DIS # H5: 1,3,9 => CTR => H5: 6,7
* DIS # I5: 6,7 => CTR => I5: 1,3,9
* DIS # D6: 6,9 => CTR => D6: 2
* DIS # B4: 6,9 => CTR => B4: 3,5,7
* DIS # I4: 6,9 => CTR => I4: 3,7
* DIS # I4: 6,9 => CTR => I4: 3,7
* DIS # H5: 6,9 => CTR => H5: 1,3,7
* DIS # I5: 6,9 => CTR => I5: 1,3,7
* DIS # H6: 6,9 => CTR => H6: 8
* PRF # H6: 8 => SOL
* PRF # B6: 6,9 => SOL
* DIS # B6: 5 => CTR => B6: 6,9
* DIS # C6: 6,9 => CTR => C6: 2,4,8
* DIS # D6: 6,9 => CTR => D6: 2
* DIS # A4: 3,8 => CTR => A4: 5
* PRF # A4: 5 => SOL
* DIS # H9: 3,8 => CTR => H9: 1,9
* DIS # H9: 3,8 => CTR => H9: 1,9
* CNT  24 HDP CHAINS /  52 HYP OPENED

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

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* PRF # A5: 2,3 => SOL
* STA A5: 2,3
* CNT   1 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

6.71............48.............4..2.....85...1...........3.87...45...6...2....... initial
6871.42.5...567.48...8.2.......41.2.....85...1...73...9..328754.457196.272.456... autosolve
687134295239567148451892367578641923362985471194273586916328754845719632723456819 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
A2: 2,3
E1: 3,9
E3: 3,9
H1: 3,9
H3: 6,7
I3: 6,7
D4: 6,9
I6: 6,9
B7: 1,6
C7: 1,6
A8: 3,8
C9: 3,8
H8: 3,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G2,G3: 1.. / G2 = 1  => 18 pairs (_) / G3 = 1  => 14 pairs (_)
H5,I5: 1.. / H5 = 1  =>  0 pairs (X) / I5 = 1  => 14 pairs (_)
B7,C7: 1.. / B7 = 1  => 12 pairs (_) / C7 = 1  => 12 pairs (_)
H9,I9: 1.. / H9 = 1  => 14 pairs (_) / I9 = 1  =>  0 pairs (X)
H5,H9: 1.. / H5 = 1  =>  0 pairs (X) / H9 = 1  => 14 pairs (_)
I5,I9: 1.. / I5 = 1  => 14 pairs (_) / I9 = 1  =>  0 pairs (X)
A2,C2: 2.. / A2 = 2  => 13 pairs (_) / C2 = 2  =>  0 pairs (X)
D5,D6: 2.. / D5 = 2  =>  0 pairs (X) / D6 = 2  => 14 pairs (_)
C6,D6: 2.. / C6 = 2  =>  0 pairs (X) / D6 = 2  => 14 pairs (_)
A2,A5: 2.. / A2 = 2  => 13 pairs (_) / A5 = 2  =>  0 pairs (X)
E1,E3: 3.. / E1 = 3  => 18 pairs (_) / E3 = 3  =>  0 pairs (X)
A8,C9: 3.. / A8 = 3  =>  0 pairs (X) / C9 = 3  => 20 pairs (_)
E1,H1: 3.. / E1 = 3  => 18 pairs (_) / H1 = 3  =>  0 pairs (X)
A8,H8: 3.. / A8 = 3  =>  0 pairs (X) / H8 = 3  => 20 pairs (_)
A3,C3: 4.. / A3 = 4  =>  0 pairs (*) / C3 = 4  =>  0 pairs (X)
G5,G6: 4.. / G5 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
C6,G6: 4.. / C6 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
A3,A5: 4.. / A3 = 4  =>  0 pairs (*) / A5 = 4  =>  0 pairs (X)
A3,B3: 5.. / A3 = 5  =>  0 pairs (X) / B3 = 5  =>  0 pairs (_)
G4,G6: 5.. / G4 = 5  =>  0 pairs (X) / G6 = 5  =>  0 pairs (_)
B6,G6: 5.. / B6 = 5  =>  0 pairs (X) / G6 = 5  =>  0 pairs (_)
A3,A4: 5.. / A3 = 5  =>  0 pairs (X) / A4 = 5  =>  0 pairs (_)
H3,I3: 6.. / H3 = 6  => 13 pairs (_) / I3 = 6  => 16 pairs (_)
B7,C7: 6.. / B7 = 6  => 12 pairs (_) / C7 = 6  => 12 pairs (_)
H3,I3: 7.. / H3 = 7  => 16 pairs (_) / I3 = 7  => 13 pairs (_)
B4,B5: 7.. / B4 = 7  => 15 pairs (_) / B5 = 7  => 16 pairs (_)
B4,I4: 7.. / B4 = 7  => 15 pairs (_) / I4 = 7  => 16 pairs (_)
H3,H5: 7.. / H3 = 7  => 16 pairs (_) / H5 = 7  => 13 pairs (_)
A8,C9: 8.. / A8 = 8  => 20 pairs (_) / C9 = 8  =>  0 pairs (X)
A8,H8: 8.. / A8 = 8  => 20 pairs (_) / H8 = 8  =>  0 pairs (X)
A4,A8: 8.. / A4 = 8  =>  0 pairs (X) / A8 = 8  => 20 pairs (_)
E1,E3: 9.. / E1 = 9  =>  0 pairs (X) / E3 = 9  => 18 pairs (_)
E1,H1: 9.. / E1 = 9  =>  0 pairs (X) / H1 = 9  => 18 pairs (_)
* DURATION: 0:00:53.615590  START: 19:45:18.515986  END: 19:46:12.131576 2017-05-04
* CP COUNT: (33)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B7,C7,C9,D4,E1,E3,H1,H3,H8,I3,I6)
* 6871.42.5...567.48...8.2.......41.2.....85...1...73...9..328754.457196.272.456...
* PAIR A2: 2,3 BLK 1
C2: 2,3,1,9                              # reduction candidate for 2,3
C2: 2,3                                  # 21 pairs
C2: 1,9                                  # 14 pairs
* PAIR A2: 2,3 COL A
A5: 2,3,4                                # reduction candidate for 2,3
A5: 2,3 => SOLVED
* 687134295239567148451892367578641923362985471194273586916328754845719632723456819
A5: 4 => CTR
* 6871342952..567.485.4892...3.8.4152.4...859.315..734869..3287548457196327234568..
* PAIR E3: 3,9 ROW 3
B3: 3,9,1,5                              # reduction candidate for 3,9
B3: 3,9 => CTR
* 6871342952..5673485348921..3.8.4152.4...859.315..734869..3287548457196327234568..
B3: 1,5                                  # 14 pairs
C3: 3,9,1,4                              # reduction candidate for 3,9
C3: 3,9 => CTR
* 687134295...5673484598.21..5...41.2.....85...1...735..9..328754845719632723456...
C3: 1,4                                  # 14 pairs
G3: 3,9,1                                # reduction candidate for 3,9
G3: 3,9                                  # 18 pairs
* PAIR H1: 3,9 BLK 3
G2: 3,9,1                                # reduction candidate for 3,9
G2: 3,9                                  # 14 pairs
G3: 3,9,1                                # reduction candidate for 3,9
G3: 3,9                                  # 18 pairs
* PAIR H1: 3,9 COL H
H5: 3,9,1,6,7                            # reduction candidate for 3,9
H5: 3,9 => CTR
* 6871342952..567.485.4892.76....41.27.7..85.3115.273.699..328754345719682728456913
H5: 1,6,7                                # 13 pairs
H9: 3,9,1,8                              # reduction candidate for 3,9
H9: 3,9 => CTR
* 6871.42.52..567.485.48.2.768...41.2.....85.1.15.2738699..328754345719682728456..1
H9: 1,8                                  # 14 pairs
* PAIR H3: 6,7 COL H
H5: 6,7,1,3,9                            # reduction candidate for 6,7
H5: 1,3,9 => CTR
* 6871.42.5...567.485.48.2.76....4152.4.2.853..15.273.699..328754.457196.272.456...
H5: 6,7                                  # 16 pairs
* PAIR I3: 6,7 COL I
I4: 6,7,3,9                              # reduction candidate for 6,7
I4: 6,7                                  # 19 pairs
I5: 6,7,1,3,9                            # reduction candidate for 6,7
I5: 6,7 => CTR
* 6871.42.5...567.48...8.2.76.7..41.23....854171542738699..328754.457196.272.456..1
I5: 1,3,9                                # 13 pairs
* PAIR D4: 6,9 BLK 5
D5: 6,9,2                                # reduction candidate for 6,9
D5: 6,9                                  # 14 pairs
D6: 6,9,2                                # reduction candidate for 6,9
D6: 6,9 => CTR
* 6871342952.9567.485.4892.673.8.4152....2859..1529734869..328754845719632723456819
D6: 2                                    # 14 pairs
* PAIR D4: 6,9 ROW 4
B4: 6,9,3,5,7                            # reduction candidate for 6,9
B4: 6,9 => CTR
* 6871.42.52..567.48...8.2.76....41.27.7..85.611...73.899..32875484571963272.456...
B4: 3,5,7                                # 13 pairs
C4: 6,9,3,8                              # reduction candidate for 6,9
C4: 6,9                                  # 15 pairs
I4: 6,9,3,7                              # reduction candidate for 6,9
I4: 6,9 => CTR
* 6871.42.5...567.48...8.2.67.7..41.2.....85.711...73.8.9..32875484571963272.456...
I4: 3,7                                  # 14 pairs
* PAIR I6: 6,9 BLK 6
I4: 6,9,3,7                              # reduction candidate for 6,9
I4: 6,9 => CTR
* 6871.42.5...567.48...8.2.67.7..41.2.....85.711...73.8.9..32875484571963272.456...
I4: 3,7                                  # 14 pairs
H5: 6,9,1,3,7                            # reduction candidate for 6,9
H5: 6,9 => CTR
* 6871.42.5...567.48...8.2.76....41.2.....85..11...73..99..328754.457196.272.456.13
H5: 1,3,7                                # 13 pairs
I5: 6,9,1,3,7                            # reduction candidate for 6,9
I5: 6,9 => CTR
* 6871.42.5...567.48...8.2.......41.2.....85.1.1...73...9..328754.457196.272.456..1
I5: 1,3,7                                # 13 pairs
H6: 6,9,8                                # reduction candidate for 6,9
H6: 6,9 => CTR
* 6871.42.5...567.48...8.2.......41.2.....854..1542738..9..328754.457196.272.456...
H6: 8 => SOLVED
* 687134295239567148451892367578641923362985471194273586916328754845719632723456819
* PAIR I6: 6,9 ROW 6
B6: 6,9,5                                # reduction candidate for 6,9
B6: 6,9 => SOLVED
* 687134295239567148451892367578641923362985471194273586916328754845719632723456819
B6: 5 => CTR
* 6871342952..567.485.4892...3.8.4152.4...859.315..734869..3287548457196327234568..
C6: 6,9,2,4,8                            # reduction candidate for 6,9
C6: 6,9 => CTR
* 687134295.9.567.485.4892.673.8.4152.....859..1592734869..328754845719632723456819
C6: 2,4,8                                # 13 pairs
D6: 6,9,2                                # reduction candidate for 6,9
D6: 6,9 => CTR
* 6871342952.9567.485.4892.673.8.4152....2859..1529734869..328754845719632723456819
D6: 2                                    # 14 pairs
* PAIR A8: 3,8 COL A
A4: 3,8,5                                # reduction candidate for 3,8
A4: 3,8 => CTR
* 6871342952..567.485.4892...3.8.4152.4...859.315..734869..3287548457196327234568..
A4: 5 => SOLVED
* 687134295239567148451892367578641923362985471194273586916328754845719632723456819
* PAIR C9: 3,8 ROW 9
G9: 3,8,9                                # reduction candidate for 3,8
G9: 3,8                                  # 21 pairs
H9: 3,8,1,9                              # reduction candidate for 3,8
H9: 3,8 => CTR
* 687134295...567.485.4892.76....4152.4.2.8531.15.273.699..328754.457196.272.4569.1
H9: 1,9                                  # 14 pairs
* PAIR C9: 3,8 COL C
C4: 3,8,6,9                              # reduction candidate for 3,8
C4: 6,9                                  # 15 pairs
C4: 3,8                                  # 14 pairs
* PAIR H8: 3,8 BLK 9
G9: 3,8,9                                # reduction candidate for 3,8
G9: 3,8                                  # 21 pairs
H9: 3,8,1,9                              # reduction candidate for 3,8
H9: 3,8 => CTR
* 687134295...567.485.4892.76....4152.4.2.8531.15.273.699..328754.457196.272.4569.1
H9: 1,9                                  # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-499-base-pr-000.dot
* REASONING
* PRF # A5: 2,3 => SOL
* DIS # A5: 4 => CTR => A5: 2,3
* DIS # B3: 3,9 => CTR => B3: 1,5
* DIS # C3: 3,9 => CTR => C3: 1,4
* DIS # H5: 3,9 => CTR => H5: 1,6,7
* DIS # H9: 3,9 => CTR => H9: 1,8
* DIS # H5: 1,3,9 => CTR => H5: 6,7
* DIS # I5: 6,7 => CTR => I5: 1,3,9
* DIS # D6: 6,9 => CTR => D6: 2
* DIS # B4: 6,9 => CTR => B4: 3,5,7
* DIS # I4: 6,9 => CTR => I4: 3,7
* DIS # I4: 6,9 => CTR => I4: 3,7
* DIS # H5: 6,9 => CTR => H5: 1,3,7
* DIS # I5: 6,9 => CTR => I5: 1,3,7
* DIS # H6: 6,9 => CTR => H6: 8
* PRF # H6: 8 => SOL
* PRF # B6: 6,9 => SOL
* DIS # B6: 5 => CTR => B6: 6,9
* DIS # C6: 6,9 => CTR => C6: 2,4,8
* DIS # D6: 6,9 => CTR => D6: 2
* DIS # A4: 3,8 => CTR => A4: 5
* PRF # A4: 5 => SOL
* DIS # H9: 3,8 => CTR => H9: 1,9
* DIS # H9: 3,8 => CTR => H9: 1,9
* CNT  24 HDP CHAINS /  52 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B7,C7,C9,D4,E1,E3,H1,H3,H8,I3,I6)
* 6871.42.5...567.48...8.2.......41.2.....85...1...73...9..328754.457196.272.456...
* PAIR A2: 2,3 BLK 1
C2: 2,3,1,9                              # reduction candidate for 2,3
C2: 2,3                                  # 21 pairs
C2: 1,9                                  # 14 pairs
* PAIR A2: 2,3 COL A
A5: 2,3,4                                # reduction candidate for 2,3
A5: 2,3 => SOLVED
* 687134295239567148451892367578641923362985471194273586916328754845719632723456819
* DURATION: 0:00:03.861395  START: 19:46:58.110901  END: 19:47:01.972296 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-499-base-pr-001.dot
* REASONING
* PRF # A5: 2,3 => SOL
* STA A5: 2,3
* CNT   1 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 499

solution: 687134295239567148451892367578641923362985471194273586916328754845719632723456819
info: 96705    FNBHYK   S8.f     35575

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

Solution

position: 687134295239567148451892367578641923362985471194273586916328754845719632723456819 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: 2,3 => UNS
* INC # C2: 1,9 => UNS
* PRF # A5: 2,3 => SOL
* DIS # A5: 4 => CTR => A5: 2,3
* DIS # B3: 3,9 => CTR => B3: 1,5
* INC # B3: 1,5 => UNS
* DIS # C3: 3,9 => CTR => C3: 1,4
* INC # C3: 1,4 => UNS
* INC # G3: 3,9 => UNS
* INC # G2: 3,9 => UNS
* INC # G3: 3,9 => UNS
* DIS # H5: 3,9 => CTR => H5: 1,6,7
* INC # H5: 1,6,7 => UNS
* DIS # H9: 3,9 => CTR => H9: 1,8
* INC # H9: 1,8 => UNS
* INC # H5: 6,7 => UNS
* DIS # H5: 1,3,9 => CTR => H5: 6,7
* INC # I4: 6,7 => UNS
* DIS # I5: 6,7 => CTR => I5: 1,3,9
* INC # I5: 1,3,9 => UNS
* INC # D5: 6,9 => UNS
* DIS # D6: 6,9 => CTR => D6: 2
* INC # D6: 2 => UNS
* DIS # B4: 6,9 => CTR => B4: 3,5,7
* INC # B4: 3,5,7 => UNS
* INC # C4: 6,9 => UNS
* DIS # I4: 6,9 => CTR => I4: 3,7
* INC # I4: 3,7 => UNS
* DIS # I4: 6,9 => CTR => I4: 3,7
* INC # I4: 3,7 => UNS
* DIS # H5: 6,9 => CTR => H5: 1,3,7
* INC # H5: 1,3,7 => UNS
* DIS # I5: 6,9 => CTR => I5: 1,3,7
* INC # I5: 1,3,7 => UNS
* DIS # H6: 6,9 => CTR => H6: 8
* PRF # H6: 8 => SOL
* PRF # B6: 6,9 => SOL
* DIS # B6: 5 => CTR => B6: 6,9
* DIS # C6: 6,9 => CTR => C6: 2,4,8
* INC # C6: 2,4,8 => UNS
* DIS # D6: 6,9 => CTR => D6: 2
* INC # D6: 2 => UNS
* DIS # A4: 3,8 => CTR => A4: 5
* PRF # A4: 5 => SOL
* INC # G9: 3,8 => UNS
* DIS # H9: 3,8 => CTR => H9: 1,9
* INC # H9: 1,9 => UNS
* INC # C4: 3,8 => UNS
* INC # C4: 6,9 => UNS
* INC # G9: 3,8 => UNS
* DIS # H9: 3,8 => CTR => H9: 1,9
* INC # H9: 1,9 => UNS
* CNT  52 HDP CHAINS /  52 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C2: 2,3 => UNS
* INC # C2: 1,9 => UNS
* PRF # A5: 2,3 => SOL
* STA A5: 2,3
* CNT   3 HDP CHAINS /   3 HYP OPENED