Analysis of xx-top500-306-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .16....4.3..2..5............4.....182..3......6...........18...7.....2......4.... initial

Autosolve

position: .168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C3: 4,8 => CTR => C3: 2,5,7,9
* DIS # F3: 1,4 => CTR => F3: 3,5,6,7,9
* DIS # C6: 1,8 => CTR => C6: 3,5,7,9
* DIS # A9: 6 => CTR => A9: 1,8
* DIS # F6: 1,4 => CTR => F6: 5,7,9
* DIS # C9: 1,8 => CTR => C9: 5,9
* CNT   6 HDP CHAINS /  29 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: 4,8 => CTR => C3: 2,5,7,9
* DIS C3: 2,5,7,9 # F3: 1,4 => CTR => F3: 3,5,6,7,9
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 # C6: 1,8 => CTR => C6: 3,5,7,9
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # A9: 6 => CTR => A9: 1,8
* PRF C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 # B3: 7 => SOL
* STA C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 + B3: 7
* CNT   5 HDP CHAINS /  24 HYP OPENED

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

Details

Positions

.16....4.3..2..5............4.....182..3......6...........18...7.....2......4.... initial
.168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42... autosolve
516893742389274561472156839943527618258361497167489325624718953791635284835942176 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
A1: 5,9
A3: 4,8
D3: 1,4
G3: 1,8
A4: 5,9
A6: 1,8
D6: 1,4
A7: 4,6
C8: 1,4
I8: 1,4
G9: 1,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F2,I2: 1.. / F2 = 1  =>  0 pairs (X) / I2 = 1  =>  7 pairs (_)
C5,F5: 1.. / C5 = 1  =>  0 pairs (X) / F5 = 1  =>  7 pairs (_)
C8,I8: 1.. / C8 = 1  =>  7 pairs (_) / I8 = 1  =>  0 pairs (X)
A6,A9: 1.. / A6 = 1  =>  7 pairs (_) / A9 = 1  =>  0 pairs (X)
D3,D6: 1.. / D3 = 1  =>  7 pairs (_) / D6 = 1  =>  0 pairs (X)
G3,G9: 1.. / G3 = 1  =>  0 pairs (X) / G9 = 1  =>  7 pairs (_)
B3,C3: 2.. / B3 = 2  => 11 pairs (_) / C3 = 2  => 11 pairs (_)
B7,C7: 2.. / B7 = 2  => 11 pairs (_) / C7 = 2  => 11 pairs (_)
B3,B7: 2.. / B3 = 2  => 11 pairs (_) / B7 = 2  => 11 pairs (_)
C3,C7: 2.. / C3 = 2  => 11 pairs (_) / C7 = 2  => 11 pairs (_)
C4,C6: 3.. / C4 = 3  => 11 pairs (_) / C6 = 3  => 12 pairs (_)
B7,B9: 3.. / B7 = 3  => 11 pairs (_) / B9 = 3  => 11 pairs (_)
E8,F8: 3.. / E8 = 3  => 11 pairs (_) / F8 = 3  => 11 pairs (_)
C4,G4: 3.. / C4 = 3  => 11 pairs (_) / G4 = 3  => 12 pairs (_)
C2,F2: 4.. / C2 = 4  =>  0 pairs (X) / F2 = 4  =>  7 pairs (_)
C8,I8: 4.. / C8 = 4  =>  0 pairs (X) / I8 = 4  =>  7 pairs (_)
A3,A7: 4.. / A3 = 4  =>  7 pairs (_) / A7 = 4  =>  0 pairs (X)
D3,D6: 4.. / D3 = 4  =>  0 pairs (X) / D6 = 4  =>  7 pairs (_)
A1,A4: 5.. / A1 = 5  => 10 pairs (_) / A4 = 5  => 15 pairs (_)
A7,A9: 6.. / A7 = 6  =>  7 pairs (_) / A9 = 6  =>  0 pairs (X)
D7,D9: 7.. / D7 = 7  => 11 pairs (_) / D9 = 7  => 11 pairs (_)
E5,E6: 8.. / E5 = 8  => 11 pairs (_) / E6 = 8  =>  7 pairs (_)
B8,H8: 8.. / B8 = 8  => 13 pairs (_) / H8 = 8  =>  7 pairs (_)
G3,G9: 8.. / G3 = 8  =>  7 pairs (_) / G9 = 8  =>  0 pairs (X)
A1,A4: 9.. / A1 = 9  => 15 pairs (_) / A4 = 9  => 10 pairs (_)
* DURATION: 0:00:40.825205  START: 13:26:28.439861  END: 13:27:09.265066 2017-05-04
* CP COUNT: (25)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A3,A4,A6,A7,C8,D3,D6,G3,G9,I8)
* .168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42...
* PAIR A1: 5,9 BLK 1
B3: 5,9,2,7,8                            # reduction candidate for 5,9
B3: 5,9                                  # 14 pairs
C3: 5,9,2,4,7,8                          # reduction candidate for 5,9
C3: 5,9                                  # 14 pairs
* PAIR A1: 5,9 ROW 1
E1: 5,9,3,7                              # reduction candidate for 5,9
E1: 5,9                                  # 14 pairs
F1: 5,9,3,7                              # reduction candidate for 5,9
F1: 5,9                                  # 14 pairs
* PAIR A3: 4,8 BLK 1
C2: 4,8,7,9                              # reduction candidate for 4,8
C2: 4,8                                  # 13 pairs
C3: 4,8,2,5,7,9                          # reduction candidate for 4,8
C3: 4,8 => CTR
* 5168...423..26.581.2.......94..2..182..3......6.....2...2.18...7.....2......42...
C3: 2,5,7,9                              # 11 pairs
* PAIR D3: 1,4 BLK 2
F2: 1,4,6,7,9                            # reduction candidate for 1,4
F2: 1,4                                  # 12 pairs
F3: 1,4,3,5,6,7,9                        # reduction candidate for 1,4
F3: 1,4 => CTR
* .168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42...
F3: 3,5,6,7,9                            # 12 pairs
* PAIR A4: 5,9 BLK 4
C4: 5,9,3,7                              # reduction candidate for 5,9
C4: 5,9                                  # 17 pairs
B5: 5,9,7,8                              # reduction candidate for 5,9
B5: 5,9                                  # 13 pairs
C5: 5,9,1,7,8                            # reduction candidate for 5,9
C5: 5,9                                  # 10 pairs
C6: 5,9,1,3,7,8                          # reduction candidate for 5,9
C6: 5,9                                  # 13 pairs
* PAIR A4: 5,9 ROW 4
D4: 5,9,6                                # reduction candidate for 5,9
D4: 5,9                                  # 14 pairs
F4: 5,9,6,7                              # reduction candidate for 5,9
F4: 5,9                                  # 17 pairs
* PAIR A6: 1,8 BLK 4
C5: 1,8,5,7,9                            # reduction candidate for 1,8
C5: 1,8                                  # 12 pairs
C6: 1,8,3,5,7,9                          # reduction candidate for 1,8
C6: 1,8 => CTR
* .168...4238.2.45.14.21..8...43.2.6182..3814..1684...2.624.18...7.1...28483..421..
C6: 3,5,7,9                              # 11 pairs
* PAIR A6: 1,8 COL A
A9: 1,8,6                                # reduction candidate for 1,8
A9: 6 => CTR
* .168...423..2..5..8..1......4..2..182..3.....16.4...2.....18...7.....2..6...42...
A9: 1,8                                  #  7 pairs
* PAIR D6: 1,4 BLK 5
F5: 1,4,5,6,7,9                          # reduction candidate for 1,4
F5: 1,4                                  # 12 pairs
F6: 1,4,5,7,9                            # reduction candidate for 1,4
F6: 1,4 => CTR
* .168...423..2..5............4..2..182.13.....86.....2.....18...7.4...2.11...428..
F6: 5,7,9                                # 12 pairs
* PAIR A7: 4,6 ROW 7
G7: 4,6,3,7,9                            # reduction candidate for 4,6
G7: 4,6                                  # 12 pairs
I7: 4,6,3,5,7,9                          # reduction candidate for 4,6
I7: 4,6                                  # 12 pairs
* PAIR G9: 1,8 ROW 9
A9: 1,8,6                                # reduction candidate for 1,8
A9: 1,8                                  #  7 pairs
C9: 1,8,5,9                              # reduction candidate for 1,8
C9: 1,8 => CTR
* .168...423..2..5..8..1......4..2..182..3.....16.4...2.....18...7.....2..6...42...
C9: 5,9                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-306-base-pr-000.dot
* REASONING
* DIS # C3: 4,8 => CTR => C3: 2,5,7,9
* DIS # F3: 1,4 => CTR => F3: 3,5,6,7,9
* DIS # C6: 1,8 => CTR => C6: 3,5,7,9
* DIS # A9: 6 => CTR => A9: 1,8
* DIS # F6: 1,4 => CTR => F6: 5,7,9
* DIS # C9: 1,8 => CTR => C9: 5,9
* CNT   6 HDP CHAINS /  29 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A3,A4,A6,A7,C8,D3,D6,G3,G9,I8)
* .168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42...
* PAIR A1: 5,9 BLK 1
B3: 5,9,2,7,8                            # reduction candidate for 5,9
B3: 5,9                                  # 14 pairs
C3: 5,9,2,4,7,8                          # reduction candidate for 5,9
C3: 5,9                                  # 14 pairs
* PAIR A1: 5,9 ROW 1
E1: 5,9,3,7                              # reduction candidate for 5,9
E1: 5,9                                  # 14 pairs
F1: 5,9,3,7                              # reduction candidate for 5,9
F1: 5,9                                  # 14 pairs
* PAIR A3: 4,8 BLK 1
C2: 4,8,7,9                              # reduction candidate for 4,8
C2: 4,8                                  # 13 pairs
C3: 4,8,2,5,7,9                          # reduction candidate for 4,8
C3: 4,8 => CTR
* 5168...423..26.581.2.......94..2..182..3......6.....2...2.18...7.....2......42...
* RESTART
* PAIR A3: 4,8 BLK 1
C2: 4,8,7,9                              # reduction candidate for 4,8
C2: 4,8                                  # 13 pairs
C2: 7,9                                  #  8 pairs
* PAIR D3: 1,4 BLK 2
F2: 1,4,6,7,9                            # reduction candidate for 1,4
F2: 1,4                                  # 12 pairs
F3: 1,4,3,5,6,7,9                        # reduction candidate for 1,4
F3: 1,4 => CTR
* .168...423..2..5............4..2..182..3......6.....2.....18...7.....2......42...
* RESTART
* PAIR A4: 5,9 BLK 4
C4: 5,9,3,7                              # reduction candidate for 5,9
C4: 5,9                                  # 18 pairs
B5: 5,9,7,8                              # reduction candidate for 5,9
B5: 5,9                                  # 14 pairs
C5: 5,9,1,7,8                            # reduction candidate for 5,9
C5: 5,9                                  # 10 pairs
C6: 5,9,1,3,7,8                          # reduction candidate for 5,9
C6: 5,9                                  # 14 pairs
* PAIR A4: 5,9 ROW 4
D4: 5,9,6                                # reduction candidate for 5,9
D4: 5,9                                  # 15 pairs
F4: 5,9,6,7                              # reduction candidate for 5,9
F4: 5,9                                  # 18 pairs
* PAIR A6: 1,8 BLK 4
C5: 1,8,5,7,9                            # reduction candidate for 1,8
C5: 1,8                                  # 13 pairs
C6: 1,8,3,5,7,9                          # reduction candidate for 1,8
C6: 1,8 => CTR
* .168...4238.2.45.14.21..8...43.2.6182..3814..1684...2.624.18...7.1...28483..421..
* RESTART
* PAIR A6: 1,8 BLK 4
C5: 1,8,5,7,9                            # reduction candidate for 1,8
C5: 1,8                                  # 13 pairs
C5: 5,7,9                                #  8 pairs
* PAIR A6: 1,8 COL A
A9: 1,8,6                                # reduction candidate for 1,8
A9: 6 => CTR
* .168...423..2..5............4..2..182..3.....16.48..2.....18...7.....2..6...42...
* PAIR RESTART

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A1,A4,B8,C9,D4,E2,F6)
* .168...423..2.45614.21.68...43.276182..3614..16.48..2.624.18...7.16..28483..421.6
* PAIR A1: 5,9 BLK 1
B3: 5,9,7                                # reduction candidate for 5,9
B3: 7 => SOLVED
* 516893742389274561472156839943527618258361497167489325624718953791635284835942176
* DURATION: 0:00:25.024291  START: 13:27:34.682544  END: 13:27:59.706835 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-306-base-pr-001.dot
* REASONING
* DIS # C3: 4,8 => CTR => C3: 2,5,7,9
* DIS C3: 2,5,7,9 # F3: 1,4 => CTR => F3: 3,5,6,7,9
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 # C6: 1,8 => CTR => C6: 3,5,7,9
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # A9: 6 => CTR => A9: 1,8
* PRF C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 # B3: 7 => SOL
* STA C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 + B3: 7
* CNT   5 HDP CHAINS /  24 HYP OPENED

Header Info

Top 500 Minimum 17 306

solution: 516893742389274561472156839943527618258361497167489325624718953791635284835942176
info: 2623     FNBTHWXY S8.f     15995

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

Solution

position: 516893742389274561472156839943527618258361497167489325624718953791635284835942176 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: 5,9 => UNS
* INC # C3: 5,9 => UNS
* INC # E1: 5,9 => UNS
* INC # F1: 5,9 => UNS
* INC # C2: 4,8 => UNS
* DIS # C3: 4,8 => CTR => C3: 2,5,7,9
* INC # C3: 2,5,7,9 => UNS
* INC # F2: 1,4 => UNS
* DIS # F3: 1,4 => CTR => F3: 3,5,6,7,9
* INC # F3: 3,5,6,7,9 => UNS
* INC # C4: 5,9 => UNS
* INC # B5: 5,9 => UNS
* INC # C5: 5,9 => UNS
* INC # C6: 5,9 => UNS
* INC # D4: 5,9 => UNS
* INC # F4: 5,9 => UNS
* INC # C5: 1,8 => UNS
* DIS # C6: 1,8 => CTR => C6: 3,5,7,9
* INC # C6: 3,5,7,9 => UNS
* INC # A9: 1,8 => UNS
* DIS # A9: 6 => CTR => A9: 1,8
* INC # F5: 1,4 => UNS
* DIS # F6: 1,4 => CTR => F6: 5,7,9
* INC # F6: 5,7,9 => UNS
* INC # G7: 4,6 => UNS
* INC # I7: 4,6 => UNS
* INC # A9: 1,8 => UNS
* DIS # C9: 1,8 => CTR => C9: 5,9
* INC # C9: 5,9 => UNS
* CNT  29 HDP CHAINS /  29 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 5,9 => UNS
* INC # C3: 5,9 => UNS
* INC # E1: 5,9 => UNS
* INC # F1: 5,9 => UNS
* INC # C2: 4,8 => UNS
* DIS # C3: 4,8 => CTR => C3: 2,5,7,9
* INC C3: 2,5,7,9 # C2: 4,8 => UNS
* INC C3: 2,5,7,9 # C2: 7,9 => UNS
* INC C3: 2,5,7,9 # F2: 1,4 => UNS
* DIS C3: 2,5,7,9 # F3: 1,4 => CTR => F3: 3,5,6,7,9
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # C4: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # B5: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # C5: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # C6: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # D4: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # F4: 5,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 # C5: 1,8 => UNS
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 # C6: 1,8 => CTR => C6: 3,5,7,9
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # C5: 1,8 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # C5: 5,7,9 => UNS
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # A9: 1,8 => UNS
* DIS C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 # A9: 6 => CTR => A9: 1,8
* INC C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 # B3: 5,9 => UNS
* PRF C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 # B3: 7 => SOL
* STA C3: 2,5,7,9 + F3: 3,5,6,7,9 + C6: 3,5,7,9 + A9: 1,8 + B3: 7
* CNT  24 HDP CHAINS /  24 HYP OPENED