Analysis of xx-top500-045-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 8.....4........6.7...35.....3.2...5.6....7.............1..3..2.7....6...4........ initial

Autosolve

position: 8.....4353....26.7...354....3.2...5.6....7...2....3...51..3..2.7....65..4....5... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C1: 1 => CTR => C1: 2,9
* DIS # B6: 4,5 => CTR => B6: 7,8,9
* DIS # H5: 1,9 => CTR => H5: 4,8
* DIS # C4: 1,9 => CTR => C4: 4,7,8
* DIS # E4: 1,9 => CTR => E4: 4,6,8
* DIS # G4: 1,9 => CTR => G4: 7,8
* PRF # I4: 1,9 => SOL
* DIS # D7: 8,9 => CTR => D7: 4,7
* DIS # C7: 8,9 => CTR => C7: 6
* DIS # I7: 8,9 => CTR => I7: 4,6
* DIS # F4: 1 => CTR => F4: 8,9
* CNT  11 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:

* DIS # C1: 1 => CTR => C1: 2,9
* PRF C1: 2,9 # B9: 2,9 => SOL
* STA C1: 2,9 + B9: 2,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

8.....4........6.7...35.....3.2...5.6....7.............1..3..2.7....6...4........ initial
8.....4353....26.7...354....3.2...5.6....7...2....3...51..3..2.7....65..4....5... autosolve
829671435345982617167354289934268751658197342271543968516739824782416593493825176 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
B1: 2,9
B2: 4,5
C2: 4,5
A3: 1,9
B3: 6,7
C3: 6,7
D1: 6,7
E1: 6,7
F1: 1,9
H2: 1,9
A4: 1,9
G5: 2,3
I5: 2,3
H6: 6,7
F7: 8,9
H9: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C1,A3: 1.. / C1 = 1  =>  0 pairs (X) / A3 = 1  => 18 pairs (_)
C1,F1: 1.. / C1 = 1  =>  0 pairs (X) / F1 = 1  => 18 pairs (_)
A3,A4: 1.. / A3 = 1  => 18 pairs (_) / A4 = 1  =>  0 pairs (X)
F1,F4: 1.. / F1 = 1  => 18 pairs (_) / F4 = 1  =>  0 pairs (X)
B1,C1: 2.. / B1 = 2  => 19 pairs (_) / C1 = 2  => 19 pairs (_)
G3,I3: 2.. / G3 = 2  => 14 pairs (_) / I3 = 2  => 14 pairs (_)
G5,I5: 2.. / G5 = 2  => 14 pairs (_) / I5 = 2  => 14 pairs (_)
E8,E9: 2.. / E8 = 2  => 17 pairs (_) / E9 = 2  => 14 pairs (_)
G3,G5: 2.. / G3 = 2  => 14 pairs (_) / G5 = 2  => 14 pairs (_)
I3,I5: 2.. / I3 = 2  => 14 pairs (_) / I5 = 2  => 14 pairs (_)
G5,I5: 3.. / G5 = 3  => 14 pairs (_) / I5 = 3  => 14 pairs (_)
C8,C9: 3.. / C8 = 3  => 16 pairs (_) / C9 = 3  => 14 pairs (_)
C8,I8: 3.. / C8 = 3  => 16 pairs (_) / I8 = 3  => 14 pairs (_)
G5,G9: 3.. / G5 = 3  => 14 pairs (_) / G9 = 3  => 14 pairs (_)
B2,C2: 4.. / B2 = 4  => 14 pairs (_) / C2 = 4  => 16 pairs (_)
D7,I7: 4.. / D7 = 4  =>  0 pairs (X) / I7 = 4  =>  9 pairs (_)
H5,H8: 4.. / H5 = 4  => 16 pairs (_) / H8 = 4  =>  0 pairs (X)
B2,C2: 5.. / B2 = 5  => 16 pairs (_) / C2 = 5  => 14 pairs (_)
D5,D6: 5.. / D5 = 5  => 16 pairs (_) / D6 = 5  => 14 pairs (_)
B3,C3: 6.. / B3 = 6  =>  9 pairs (_) / C3 = 6  =>  0 pairs (X)
D1,E1: 6.. / D1 = 6  => 14 pairs (_) / E1 = 6  =>  0 pairs (X)
E4,I4: 6.. / E4 = 6  => 14 pairs (_) / I4 = 6  =>  0 pairs (X)
C7,I7: 6.. / C7 = 6  =>  9 pairs (_) / I7 = 6  =>  0 pairs (X)
B3,B9: 6.. / B3 = 6  =>  9 pairs (_) / B9 = 6  =>  0 pairs (X)
D1,D6: 6.. / D1 = 6  => 14 pairs (_) / D6 = 6  =>  0 pairs (X)
H6,H9: 6.. / H6 = 6  =>  9 pairs (_) / H9 = 6  =>  0 pairs (X)
B3,C3: 7.. / B3 = 7  =>  0 pairs (X) / C3 = 7  =>  9 pairs (_)
D1,E1: 7.. / D1 = 7  =>  0 pairs (X) / E1 = 7  => 14 pairs (_)
C4,G4: 7.. / C4 = 7  =>  0 pairs (X) / G4 = 7  =>  9 pairs (_)
D7,G7: 7.. / D7 = 7  =>  9 pairs (_) / G7 = 7  =>  0 pairs (X)
B3,B6: 7.. / B3 = 7  =>  0 pairs (X) / B6 = 7  =>  9 pairs (_)
E1,E9: 7.. / E1 = 7  => 14 pairs (_) / E9 = 7  =>  0 pairs (X)
H6,H9: 7.. / H6 = 7  =>  0 pairs (X) / H9 = 7  =>  9 pairs (_)
D2,E2: 8.. / D2 = 8  => 17 pairs (_) / E2 = 8  => 17 pairs (_)
F4,F7: 8.. / F4 = 8  => 18 pairs (_) / F7 = 8  => 19 pairs (_)
A3,A4: 9.. / A3 = 9  =>  0 pairs (X) / A4 = 9  => 18 pairs (_)
* DURATION: 0:01:05.553290  START: 04:11:45.570345  END: 04:12:51.123635 2017-05-04
* CP COUNT: (36)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B1,B2,B3,C2,C3,D1,E1,F1,F7,G5,H2,H6,H9,I5)
* 8.....4353....26.7...354....3.2...5.6....7...2....3...51..3..2.7....65..4....5...
* PAIR B1: 2,9 BLK 1
C1: 2,9,1                                # reduction candidate for 2,9
C1: 1 => CTR
* 821..94353....26979..354...13.2.8.5.6....7...2....3...51..3..2.7....65..4....5...
C1: 2,9                                  # 18 pairs
* PAIR B1: 2,9 COL B
B8: 2,9,8                                # reduction candidate for 2,9
B8: 2,9                                  # 18 pairs
B9: 2,9,6,8                              # reduction candidate for 2,9
B9: 2,9                                  # 12 pairs
* PAIR B2: 4,5 COL B
B5: 4,5,8,9                              # reduction candidate for 4,5
B5: 4,5                                  # 17 pairs
B6: 4,5,7,8,9                            # reduction candidate for 4,5
B6: 4,5 => CTR
* 8.....4353....26.7.76354....3.2...5.6....7...2....3...51..3..267....65..46...5.7.
B6: 7,8,9                                # 17 pairs
* PAIR C2: 4,5 COL C
C5: 4,5,1,8,9                            # reduction candidate for 4,5
C5: 4,5                                  # 19 pairs
C6: 4,5,1,7,8,9                          # reduction candidate for 4,5
C6: 4,5                                  # 19 pairs
* PAIR A3: 1,9 BLK 1
C1: 1,9,2                                # reduction candidate for 1,9
C1: 2                                    # 19 pairs
C1: 1,9                                  # 19 pairs
* PAIR A3: 1,9 ROW 3
G3: 1,9,2,8                              # reduction candidate for 1,9
G3: 1,9                                  # 15 pairs
H3: 1,9,8                                # reduction candidate for 1,9
H3: 1,9                                  # 21 pairs
I3: 1,9,2,8                              # reduction candidate for 1,9
I3: 1,9                                  # 15 pairs
* PAIR F1: 1,9 BLK 2
D2: 1,9,8                                # reduction candidate for 1,9
D2: 1,9                                  # 17 pairs
E2: 1,9,8                                # reduction candidate for 1,9
E2: 1,9                                  # 17 pairs
* PAIR F1: 1,9 ROW 1
C1: 1,9,2                                # reduction candidate for 1,9
C1: 2                                    # 19 pairs
C1: 1,9                                  # 19 pairs
* PAIR F1: 1,9 COL F
F4: 1,9,8                                # reduction candidate for 1,9
F4: 1,9                                  # 19 pairs
F4: 8                                    # 18 pairs
* PAIR H2: 1,9 BLK 3
G3: 1,9,2,8                              # reduction candidate for 1,9
G3: 1,9                                  # 15 pairs
H3: 1,9,8                                # reduction candidate for 1,9
H3: 1,9                                  # 21 pairs
I3: 1,9,2,8                              # reduction candidate for 1,9
I3: 1,9                                  # 15 pairs
* PAIR H2: 1,9 ROW 2
D2: 1,9,8                                # reduction candidate for 1,9
D2: 1,9                                  # 17 pairs
E2: 1,9,8                                # reduction candidate for 1,9
E2: 1,9                                  # 17 pairs
* PAIR H2: 1,9 COL H
H5: 1,9,4,8                              # reduction candidate for 1,9
H5: 1,9 => CTR
* 8.....4353....26.7.67354.8..3.2...5.6....7...27...3...51.43.72.7....654.4....5.6.
H5: 4,8                                  # 17 pairs
H8: 1,9,4,8                              # reduction candidate for 1,9
H8: 1,9                                  # 17 pairs
* PAIR A4: 1,9 BLK 4
C4: 1,9,4,7,8                            # reduction candidate for 1,9
C4: 1,9 => CTR
* 8.....4353....26.7...354....3.2..75.6....7...2....3.6.51.73..247....65..4....5.76
C4: 4,7,8                                # 16 pairs
C5: 1,9,4,5,8                            # reduction candidate for 1,9
C5: 1,9                                  # 17 pairs
C6: 1,9,4,5,7,8                          # reduction candidate for 1,9
C6: 1,9                                  # 17 pairs
* PAIR A4: 1,9 ROW 4
E4: 1,9,4,6,8                            # reduction candidate for 1,9
E4: 1,9 => CTR
* 8.....4353....26.7...354....3.2...566....7...2....3.7.516.3..2.7....65..4....5...
E4: 4,6,8                                # 16 pairs
F4: 1,9,8                                # reduction candidate for 1,9
F4: 1,9                                  # 19 pairs
G4: 1,9,7,8                              # reduction candidate for 1,9
G4: 1,9 => CTR
* 8.....4353....26.7.76354....372...5.6....7...2....3...51..3..267....65..46...5.7.
G4: 7,8                                  # 17 pairs
I4: 1,9,4,6,8                            # reduction candidate for 1,9
I4: 1,9 => SOLVED
* 829671435345982617167354289934268751658197342271543968516739824782416593493825176
I4: 4,6,8                                # 16 pairs
* PAIR F7: 8,9 BLK 8
D7: 8,9,4,7                              # reduction candidate for 8,9
D7: 8,9 => CTR
* 8.....4353....26.7.67354....3.2...5.6....7.4.27...3...51..3.7247....65..4....5.6.
D7: 4,7                                  # 17 pairs
D8: 8,9,1,4                              # reduction candidate for 8,9
D8: 8,9                                  # 19 pairs
E8: 8,9,1,2,4                            # reduction candidate for 8,9
E8: 8,9                                  # 19 pairs
D9: 8,9,1,7                              # reduction candidate for 8,9
D9: 8,9                                  # 19 pairs
E9: 8,9,1,2,7                            # reduction candidate for 8,9
E9: 8,9                                  # 20 pairs
* PAIR F7: 8,9 ROW 7
C7: 8,9,6                                # reduction candidate for 8,9
C7: 8,9 => CTR
* 8.....4353....26.7...354....3.2...5.6....7...2....3...51..3..267....65..4....5.7.
C7: 6                                    #  9 pairs
G7: 8,9,7                                # reduction candidate for 8,9
G7: 8,9                                  #  9 pairs
I7: 8,9,4,6                              # reduction candidate for 8,9
I7: 8,9 => CTR
* 8.....4353....26.7.67354....3.2...5.6....7...27...3...51643.72.7....65..4....5.6.
I7: 4,6                                  # 17 pairs
* PAIR F7: 8,9 COL F
F4: 8,9,1                                # reduction candidate for 8,9
F4: 1 => CTR
* 8.1..94353....26979..354....3.2.1.5.6....7...2....3...51..38.2.7....65..4....5...
F4: 8,9                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-045-base-pr-000.dot
* REASONING
* DIS # C1: 1 => CTR => C1: 2,9
* DIS # B6: 4,5 => CTR => B6: 7,8,9
* DIS # H5: 1,9 => CTR => H5: 4,8
* DIS # C4: 1,9 => CTR => C4: 4,7,8
* DIS # E4: 1,9 => CTR => E4: 4,6,8
* DIS # G4: 1,9 => CTR => G4: 7,8
* PRF # I4: 1,9 => SOL
* DIS # D7: 8,9 => CTR => D7: 4,7
* DIS # C7: 8,9 => CTR => C7: 6
* DIS # I7: 8,9 => CTR => I7: 4,6
* DIS # F4: 1 => CTR => F4: 8,9
* CNT  11 HDP CHAINS /  52 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B1,B2,B3,C2,C3,D1,E1,F1,F7,G5,H2,H6,H9,I5)
* 8.....4353....26.7...354....3.2...5.6....7...2....3...51..3..2.7....65..4....5...
* PAIR B1: 2,9 BLK 1
C1: 2,9,1                                # reduction candidate for 2,9
C1: 1 => CTR
* 821..94353....26979..354...13.2.8.5.6....7...2....3...51..3..2.7....65..4....5...
* PAIR B1: 2,9 COL B
B8: 2,9,8                                # reduction candidate for 2,9
B8: 2,9                                  # 20 pairs
B9: 2,9,6,8                              # reduction candidate for 2,9
B9: 2,9 => SOLVED
* 829671435345982617167354289934268751658197342271543968516739824782416593493825176
* DURATION: 0:00:05.743893  START: 04:13:41.855480  END: 04:13:47.599373 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-045-base-pr-001.dot
* REASONING
* DIS # C1: 1 => CTR => C1: 2,9
* PRF C1: 2,9 # B9: 2,9 => SOL
* STA C1: 2,9 + B9: 2,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 045

solution: 829671435345982617167354289934268751658197342271543968516739824782416593493825176
info: 1377     FNBHXY   S8.f     41710

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

Solution

position: 829671435345982617167354289934268751658197342271543968516739824782416593493825176 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 # C1: 2,9 => UNS
* DIS # C1: 1 => CTR => C1: 2,9
* INC # B8: 2,9 => UNS
* INC # B9: 2,9 => UNS
* INC # B5: 4,5 => UNS
* DIS # B6: 4,5 => CTR => B6: 7,8,9
* INC # B6: 7,8,9 => UNS
* INC # C5: 4,5 => UNS
* INC # C6: 4,5 => UNS
* INC # C1: 1,9 => UNS
* INC # C1: 2 => UNS
* INC # G3: 1,9 => UNS
* INC # H3: 1,9 => UNS
* INC # I3: 1,9 => UNS
* INC # D2: 1,9 => UNS
* INC # E2: 1,9 => UNS
* INC # C1: 1,9 => UNS
* INC # C1: 2 => UNS
* INC # F4: 1,9 => UNS
* INC # F4: 8 => UNS
* INC # G3: 1,9 => UNS
* INC # H3: 1,9 => UNS
* INC # I3: 1,9 => UNS
* INC # D2: 1,9 => UNS
* INC # E2: 1,9 => UNS
* DIS # H5: 1,9 => CTR => H5: 4,8
* INC # H5: 4,8 => UNS
* INC # H8: 1,9 => UNS
* DIS # C4: 1,9 => CTR => C4: 4,7,8
* INC # C4: 4,7,8 => UNS
* INC # C5: 1,9 => UNS
* INC # C6: 1,9 => UNS
* DIS # E4: 1,9 => CTR => E4: 4,6,8
* INC # E4: 4,6,8 => UNS
* INC # F4: 1,9 => UNS
* DIS # G4: 1,9 => CTR => G4: 7,8
* INC # G4: 7,8 => UNS
* PRF # I4: 1,9 => SOL
* INC # I4: 4,6,8 => UNS
* DIS # D7: 8,9 => CTR => D7: 4,7
* INC # D7: 4,7 => UNS
* INC # D8: 8,9 => UNS
* INC # E8: 8,9 => UNS
* INC # D9: 8,9 => UNS
* INC # E9: 8,9 => UNS
* DIS # C7: 8,9 => CTR => C7: 6
* INC # C7: 6 => UNS
* INC # G7: 8,9 => UNS
* DIS # I7: 8,9 => CTR => I7: 4,6
* INC # I7: 4,6 => UNS
* INC # F4: 8,9 => UNS
* DIS # F4: 1 => CTR => F4: 8,9
* CNT  52 HDP CHAINS /  52 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C1: 2,9 => UNS
* DIS # C1: 1 => CTR => C1: 2,9
* INC C1: 2,9 # B8: 2,9 => UNS
* PRF C1: 2,9 # B9: 2,9 => SOL
* STA C1: 2,9 + B9: 2,9
* CNT   4 HDP CHAINS /   4 HYP OPENED