Analysis of xx-top500-196-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 7...5...........41....2.......6..2........37..18.......6.1.8...3.....5.....4..... initial

Autosolve

position: 7...51..........411...24......6.921.6...1237.218.......6.1.8...3.12..5.....4.51.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I4: 4,5 => CTR => I4: 8
* PRF # I4: 8 => SOL
* DIS # A7: 9 => CTR => A7: 4,5
* PRF # I4: 4,8 => SOL
* DIS # I4: 5 => CTR => I4: 4,8
* PRF # I5: 5,8 => SOL
* DIS # I5: 4 => CTR => I5: 5,8
* DIS # D6: 3,7 => CTR => D6: 5
* PRF # D6: 5 => SOL
* DIS # F2: 3,7 => CTR => F2: 6
* PRF # B8: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 2,7
* DIS # A2: 5 => CTR => A2: 8,9
* DIS # I8: 6,7 => CTR => I8: 4,9
* DIS # F2: 3 => CTR => F2: 6,7
* CNT  15 HDP CHAINS /  28 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 # I4: 4,5 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

7...5...........41....2.......6..2........37..18.......6.1.8...3.....5.....4..... initial
7...51..........411...24......6.921.6...1237.218.......6.1.8...3.12..5.....4.51.. autosolve
784951632952386741136724859573649218649812375218573496465138927391267584827495163 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
A4: 4,5
B4: 3,7
C4: 3,7
E4: 4,8
D5: 5,8
E6: 4,7
F6: 3,7
A9: 8,9
F8: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,C2: 2.. / B2 = 2  =>  0 pairs (X) / C2 = 2  => 10 pairs (_)
H1,I1: 2.. / H1 = 2  => 10 pairs (_) / I1 = 2  =>  9 pairs (_)
B2,B9: 2.. / B2 = 2  =>  0 pairs (X) / B9 = 2  => 10 pairs (_)
B4,C4: 3.. / B4 = 3  =>  9 pairs (_) / C4 = 3  =>  8 pairs (_)
D6,F6: 3.. / D6 = 3  =>  0 pairs (X) / F6 = 3  => 10 pairs (_)
E7,E9: 3.. / E7 = 3  => 10 pairs (_) / E9 = 3  => 11 pairs (_)
F2,F6: 3.. / F2 = 3  =>  0 pairs (X) / F6 = 3  => 10 pairs (_)
B1,C1: 4.. / B1 = 4  =>  0 pairs (X) / C1 = 4  => 10 pairs (_)
E4,E6: 4.. / E4 = 4  =>  0 pairs (*) / E6 = 4  =>  0 pairs (X)
B8,I8: 4.. / B8 = 4  =>  0 pairs (X) / I8 = 4  =>  0 pairs (_)
A4,A7: 4.. / A4 = 4  =>  0 pairs (X) / A7 = 4  =>  0 pairs (_)
G6,G7: 4.. / G6 = 4  =>  0 pairs (*) / G7 = 4  =>  0 pairs (X)
H3,I3: 5.. / H3 = 5  => 10 pairs (_) / I3 = 5  =>  0 pairs (X)
D5,D6: 5.. / D5 = 5  =>  0 pairs (X) / D6 = 5  =>  0 pairs (_)
A7,C7: 5.. / A7 = 5  =>  0 pairs (X) / C7 = 5  => 11 pairs (_)
A4,I4: 5.. / A4 = 5  =>  0 pairs (*) / I4 = 5  =>  0 pairs (X)
B2,B5: 5.. / B2 = 5  => 14 pairs (_) / B5 = 5  =>  0 pairs (X)
H3,H6: 5.. / H3 = 5  => 10 pairs (_) / H6 = 5  =>  0 pairs (X)
C1,C3: 6.. / C1 = 6  =>  0 pairs (X) / C3 = 6  =>  9 pairs (_)
E2,F2: 6.. / E2 = 6  =>  0 pairs (X) / F2 = 6  => 11 pairs (_)
F2,F8: 6.. / F2 = 6  => 11 pairs (_) / F8 = 6  =>  0 pairs (X)
B4,C4: 7.. / B4 = 7  =>  8 pairs (_) / C4 = 7  =>  9 pairs (_)
E4,D5: 8.. / E4 = 8  =>  0 pairs (X) / D5 = 8  =>  0 pairs (_)
I4,I5: 8.. / I4 = 8  =>  0 pairs (*) / I5 = 8  =>  0 pairs (X)
H8,H9: 8.. / H8 = 8  =>  9 pairs (_) / H9 = 8  =>  0 pairs (X)
E4,I4: 8.. / E4 = 8  =>  0 pairs (X) / I4 = 8  =>  0 pairs (_)
D5,I5: 8.. / D5 = 8  =>  0 pairs (*) / I5 = 8  =>  0 pairs (X)
B8,H8: 8.. / B8 = 8  =>  0 pairs (X) / H8 = 8  =>  9 pairs (_)
A2,A9: 8.. / A2 = 8  =>  0 pairs (X) / A9 = 8  =>  9 pairs (_)
E2,E4: 8.. / E2 = 8  =>  0 pairs (*) / E4 = 8  =>  0 pairs (X)
B5,C5: 9.. / B5 = 9  => 15 pairs (_) / C5 = 9  => 12 pairs (_)
* DURATION: 0:00:50.561178  START: 09:26:24.604206  END: 09:27:15.165384 2017-05-04
* CP COUNT: (31)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B4,C4,D5,E4,E6,F6,F8)
* 7...51..........411...24......6.921.6...1237.218.......6.1.8...3.12..5.....4.51..
* PAIR A4: 4,5 BLK 4
B5: 4,5,9                                # reduction candidate for 4,5
B5: 4,5                                  # 12 pairs
C5: 4,5,9                                # reduction candidate for 4,5
C5: 4,5                                  # 15 pairs
* PAIR A4: 4,5 ROW 4
I4: 4,5,8                                # reduction candidate for 4,5
I4: 4,5 => CTR
* 7...51..........411...24......68921.6..512378218.4.....6.1.84..3412..58....4.51..
I4: 8 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
* PAIR A4: 4,5 COL A
A7: 4,5,9                                # reduction candidate for 4,5
A7: 9 => CTR
* 7...51..........411...24...4..6892156...1237.218.......6.1.8...3.12..5.....4.51..
A7: 4,5                                  # 14 pairs
* PAIR E4: 4,8 ROW 4
I4: 4,8,5                                # reduction candidate for 4,8
I4: 4,8 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
I4: 5 => CTR
* 7...51..........411...24......6892156..512378218.4.....6.1.84..3412..58....4.51..
* PAIR D5: 5,8 ROW 5
I5: 5,8,4                                # reduction candidate for 5,8
I5: 5,8 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
I5: 4 => CTR
* 7...51..........411...24......6.92186..81237421854.....6.1.8...3.12..5.....4.51..
* PAIR F6: 3,7 BLK 5
D6: 3,7,5                                # reduction candidate for 3,7
D6: 3,7 => CTR
* 7...51....52....411...24...5..6892146..512378218.4....4651.8...3.12..5...2.4.51..
D6: 5 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
* PAIR F6: 3,7 COL F
F2: 3,7,6                                # reduction candidate for 3,7
F2: 3,7 => CTR
* 7...51.......6..411...24......68921.6..512378218.4.....6.1.84..3412.658....4.51..
F2: 6                                    # 11 pairs
* PAIR A9: 8,9 BLK 7
B8: 8,9,4,7                              # reduction candidate for 8,9
B8: 8,9 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
B8: 4,7                                  # 10 pairs
B9: 8,9,2,7                              # reduction candidate for 8,9
B9: 8,9 => CTR
* 7...51....2.....411...24......6.921.659812374218.......6.1.8...3.12..5.....4.51..
B9: 2,7                                  # 10 pairs
* PAIR A9: 8,9 ROW 9
H9: 8,9,2,3,6                            # reduction candidate for 8,9
H9: 8,9                                  # 14 pairs
H9: 2,3,6                                #  9 pairs
* PAIR A9: 8,9 COL A
A2: 8,9,5                                # reduction candidate for 8,9
A2: 5 => CTR
* 7...51...5......411...24...4..6892156...1237.218.......6.1.8...3.12..5.....4.51..
A2: 8,9                                  # 14 pairs
* PAIR F8: 6,7 BLK 8
E8: 6,7,9                                # reduction candidate for 6,7
E8: 6,7                                  # 14 pairs
E9: 6,7,3,9                              # reduction candidate for 6,7
E9: 6,7                                  # 12 pairs
* PAIR F8: 6,7 ROW 8
I8: 6,7,4,9                              # reduction candidate for 6,7
I8: 6,7 => CTR
* 7.4.51..........411.6.24...4..6892156...1237.218.......6.1.8...3412..58....4.51..
I8: 4,9                                  # 10 pairs
* PAIR F8: 6,7 COL F
F2: 6,7,3                                # reduction candidate for 6,7
F2: 3 => CTR
* 7...51.......63.411...24......68921.6..512378218347....6.1.84..3412.658....4.51..
F2: 6,7                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-196-base-pr-000.dot
* REASONING
* DIS # I4: 4,5 => CTR => I4: 8
* PRF # I4: 8 => SOL
* DIS # A7: 9 => CTR => A7: 4,5
* PRF # I4: 4,8 => SOL
* DIS # I4: 5 => CTR => I4: 4,8
* PRF # I5: 5,8 => SOL
* DIS # I5: 4 => CTR => I5: 5,8
* DIS # D6: 3,7 => CTR => D6: 5
* PRF # D6: 5 => SOL
* DIS # F2: 3,7 => CTR => F2: 6
* PRF # B8: 8,9 => SOL
* DIS # B9: 8,9 => CTR => B9: 2,7
* DIS # A2: 5 => CTR => A2: 8,9
* DIS # I8: 6,7 => CTR => I8: 4,9
* DIS # F2: 3 => CTR => F2: 6,7
* CNT  15 HDP CHAINS /  28 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,A9,B4,C4,D5,E4,E6,F6,F8)
* 7...51..........411...24......6.921.6...1237.218.......6.1.8...3.12..5.....4.51..
* PAIR A4: 4,5 BLK 4
B5: 4,5,9                                # reduction candidate for 4,5
B5: 4,5                                  # 12 pairs
C5: 4,5,9                                # reduction candidate for 4,5
C5: 4,5                                  # 15 pairs
* PAIR A4: 4,5 ROW 4
I4: 4,5,8                                # reduction candidate for 4,5
I4: 4,5 => CTR
* 7...51..........411...24......68921.6..512378218.4.....6.1.84..3412..58....4.51..
I4: 8 => SOLVED
* 784951632952386741136724859573649218649812375218573496465138927391267584827495163
* DURATION: 0:00:05.003121  START: 09:27:42.222760  END: 09:27:47.225881 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-196-base-pr-001.dot
* REASONING
* DIS # I4: 4,5 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 196

solution: 784951632952386741136724859573649218649812375218573496465138927391267584827495163
info: 1880     FNBHWY   S8.f     36719

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

Solution

position: 784951632952386741136724859573649218649812375218573496465138927391267584827495163 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 # B5: 4,5 => UNS
* INC # C5: 4,5 => UNS
* DIS # I4: 4,5 => CTR => I4: 8
* PRF # I4: 8 => SOL
* INC # A7: 4,5 => UNS
* DIS # A7: 9 => CTR => A7: 4,5
* PRF # I4: 4,8 => SOL
* DIS # I4: 5 => CTR => I4: 4,8
* PRF # I5: 5,8 => SOL
* DIS # I5: 4 => CTR => I5: 5,8
* DIS # D6: 3,7 => CTR => D6: 5
* PRF # D6: 5 => SOL
* DIS # F2: 3,7 => CTR => F2: 6
* INC # F2: 6 => UNS
* PRF # B8: 8,9 => SOL
* INC # B8: 4,7 => UNS
* DIS # B9: 8,9 => CTR => B9: 2,7
* INC # B9: 2,7 => UNS
* INC # H9: 8,9 => UNS
* INC # H9: 2,3,6 => UNS
* INC # A2: 8,9 => UNS
* DIS # A2: 5 => CTR => A2: 8,9
* INC # E8: 6,7 => UNS
* INC # E9: 6,7 => UNS
* DIS # I8: 6,7 => CTR => I8: 4,9
* INC # I8: 4,9 => UNS
* INC # F2: 6,7 => UNS
* DIS # F2: 3 => CTR => F2: 6,7
* CNT  28 HDP CHAINS /  28 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B5: 4,5 => UNS
* INC # C5: 4,5 => UNS
* DIS # I4: 4,5 => CTR => I4: 8
* PRF I4: 8 => SOL
* STA I4: 8
* CNT   4 HDP CHAINS /   3 HYP OPENED