Analysis of xx-top500-090-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 7..4.86..........13.........5..21...4......7............235.......7..4...1....... initial

Autosolve

position: 7914386..24..753.13.51.27.4.57.21.4342...317.1...472...72354.1.5..71.4...1428.537 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C6: 6,8 => CTR => C6: 3,9
* PRF # C8: 6,8 => SOL
* DIS # D5: 6,9 => CTR => D5: 5,8
* DIS # D6: 6,9 => CTR => D6: 5,8
* DIS # D5: 6,9 => CTR => D5: 5,8
* DIS # D6: 6,9 => CTR => D6: 5,8
* DIS # I5: 6,9 => CTR => I5: 5,8
* DIS # A4: 8,9 => CTR => A4: 6
* PRF # A4: 6 => SOL
* PRF # D4: 8,9 => SOL
* DIS # D4: 6 => CTR => D4: 8,9
* DIS # A7: 6,9 => CTR => A7: 8
* PRF # C8: 6,9 => SOL
* DIS # A4: 8 => CTR => A4: 6,9
* PRF # C8: 6,9 => SOL
* DIS # I8: 6,9 => CTR => I8: 2,8
* DIS # I7: 8,9 => CTR => I7: 6
* DIS # A7: 6 => CTR => A7: 8,9
* DIS # I8: 2,6 => CTR => I8: 8,9
* CNT  19 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 # C6: 6,8 => CTR => C6: 3,9
* PRF C6: 3,9 # C8: 6,8 => SOL
* STA C6: 3,9 + C8: 6,8
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

7..4.86..........13.........5..21...4......7............235.......7..4...1....... initial
7914386..24..753.13.51.27.4.57.21.4342...317.1...472...72354.1.5..71.4...1428.537 autosolve
791438652248675391365192784657921843429863175183547269872354916536719428914286537 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
C2: 6,8
B3: 6,8
D2: 6,9
E3: 6,9
H1: 2,5
I1: 2,5
H2: 8,9
H3: 8,9
E5: 6,9
G4: 8,9
H6: 5,6
A9: 6,9
F8: 6,9
F9: 6,9
G7: 8,9
H8: 2,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H1,I1: 2.. / H1 = 2  =>  0 pairs (X) / I1 = 2  => 13 pairs (_)
H8,I8: 2.. / H8 = 2  => 13 pairs (_) / I8 = 2  =>  0 pairs (X)
H1,H8: 2.. / H1 = 2  =>  0 pairs (X) / H8 = 2  => 13 pairs (_)
I1,I8: 2.. / I1 = 2  => 13 pairs (_) / I8 = 2  =>  0 pairs (X)
B6,C6: 3.. / B6 = 3  => 18 pairs (_) / C6 = 3  => 17 pairs (_)
B8,C8: 3.. / B8 = 3  => 17 pairs (_) / C8 = 3  => 18 pairs (_)
B6,B8: 3.. / B6 = 3  => 18 pairs (_) / B8 = 3  => 17 pairs (_)
C6,C8: 3.. / C6 = 3  => 17 pairs (_) / C8 = 3  => 18 pairs (_)
H1,I1: 5.. / H1 = 5  => 13 pairs (_) / I1 = 5  =>  0 pairs (X)
D5,D6: 5.. / D5 = 5  => 16 pairs (_) / D6 = 5  => 14 pairs (_)
D5,I5: 5.. / D5 = 5  => 16 pairs (_) / I5 = 5  => 14 pairs (_)
H1,H6: 5.. / H1 = 5  => 13 pairs (_) / H6 = 5  =>  0 pairs (X)
C2,B3: 6.. / C2 = 6  =>  0 pairs (X) / B3 = 6  =>  0 pairs (_)
D2,E3: 6.. / D2 = 6  =>  0 pairs (*) / E3 = 6  =>  0 pairs (X)
F8,F9: 6.. / F8 = 6  =>  0 pairs (X) / F9 = 6  => 15 pairs (_)
C2,D2: 6.. / C2 = 6  =>  0 pairs (X) / D2 = 6  =>  0 pairs (_)
B3,E3: 6.. / B3 = 6  =>  0 pairs (*) / E3 = 6  =>  0 pairs (X)
A4,D4: 6.. / A4 = 6  =>  0 pairs (*) / D4 = 6  =>  0 pairs (X)
A7,I7: 6.. / A7 = 6  =>  0 pairs (X) / I7 = 6  => 15 pairs (_)
A9,F9: 6.. / A9 = 6  =>  0 pairs (X) / F9 = 6  => 15 pairs (_)
E3,E5: 6.. / E3 = 6  =>  0 pairs (X) / E5 = 6  =>  0 pairs (_)
H6,H8: 6.. / H6 = 6  => 13 pairs (_) / H8 = 6  =>  0 pairs (X)
C2,B3: 8.. / C2 = 8  =>  0 pairs (*) / B3 = 8  =>  0 pairs (X)
H2,H3: 8.. / H2 = 8  =>  0 pairs (X) / H3 = 8  =>  0 pairs (_)
C2,H2: 8.. / C2 = 8  =>  0 pairs (*) / H2 = 8  =>  0 pairs (X)
B3,H3: 8.. / B3 = 8  =>  0 pairs (X) / H3 = 8  =>  0 pairs (_)
A4,A7: 8.. / A4 = 8  =>  0 pairs (X) / A7 = 8  => 18 pairs (_)
G4,G7: 8.. / G4 = 8  => 18 pairs (_) / G7 = 8  =>  0 pairs (X)
D2,E3: 9.. / D2 = 9  =>  0 pairs (X) / E3 = 9  =>  0 pairs (_)
H2,H3: 9.. / H2 = 9  =>  0 pairs (*) / H3 = 9  =>  0 pairs (X)
F8,F9: 9.. / F8 = 9  => 15 pairs (_) / F9 = 9  =>  0 pairs (X)
D2,H2: 9.. / D2 = 9  =>  0 pairs (X) / H2 = 9  =>  0 pairs (_)
E3,H3: 9.. / E3 = 9  =>  0 pairs (*) / H3 = 9  =>  0 pairs (X)
A9,F9: 9.. / A9 = 9  => 15 pairs (_) / F9 = 9  =>  0 pairs (X)
E3,E5: 9.. / E3 = 9  =>  0 pairs (*) / E5 = 9  =>  0 pairs (X)
G4,G7: 9.. / G4 = 9  =>  0 pairs (X) / G7 = 9  => 18 pairs (_)
* DURATION: 0:01:01.597440  START: 05:51:22.620136  END: 05:52:24.217576 2017-05-04
* CP COUNT: (36)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B3,C2,D2,E3,E5,F8,F9,G4,G7,H1,H2,H3,H6,H8,I1)
* 7914386..24..753.13.51.27.4.57.21.4342...317.1...472...72354.1.5..71.4...1428.537
* PAIR C2: 6,8 COL C
C5: 6,8,9                                # reduction candidate for 6,8
C5: 6,8                                  # 19 pairs
C6: 6,8,3,9                              # reduction candidate for 6,8
C6: 6,8 => CTR
* 7914386..24.675391365192784657.21.43429.6317.138.472...72354.1.5.371.4...1428.537
C6: 3,9                                  # 17 pairs
C8: 6,8,3,9                              # reduction candidate for 6,8
C8: 6,8 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
C8: 3,9                                  # 17 pairs
* PAIR B3: 6,8 COL B
B6: 6,8,3                                # reduction candidate for 6,8
B6: 6,8                                  # 17 pairs
B8: 6,8,3                                # reduction candidate for 6,8
B8: 6,8                                  # 18 pairs
* PAIR D2: 6,9 COL D
D4: 6,9,8                                # reduction candidate for 6,9
D4: 6,9                                  # 19 pairs
D5: 6,9,5,8                              # reduction candidate for 6,9
D5: 6,9 => CTR
* 79143865224..753.13.51.27.4.57821943428..3175139547268872354.1.5..71.42..1428.537
D5: 5,8                                  # 17 pairs
D6: 6,9,5,8                              # reduction candidate for 6,9
D6: 6,9 => CTR
* 7914386..24..753.13.51.27.4.5782194342.5.317.1...472..872354.1.5..71.4...1428.537
D6: 5,8                                  # 17 pairs
* PAIR E5: 6,9 BLK 5
D4: 6,9,8                                # reduction candidate for 6,9
D4: 6,9                                  # 19 pairs
D5: 6,9,5,8                              # reduction candidate for 6,9
D5: 6,9 => CTR
* 79143865224..753.13.51.27.4.57821943428..3175139547268872354.1.5..71.42..1428.537
D5: 5,8                                  # 17 pairs
D6: 6,9,5,8                              # reduction candidate for 6,9
D6: 6,9 => CTR
* 7914386..24..753.13.51.27.4.5782194342.5.317.1...472..872354.1.5..71.4...1428.537
D6: 5,8                                  # 17 pairs
* PAIR E5: 6,9 ROW 5
C5: 6,9,8                                # reduction candidate for 6,9
C5: 6,9                                  # 20 pairs
I5: 6,9,5,8                              # reduction candidate for 6,9
I5: 6,9 => CTR
* 7914386522469753813851627.4.57.21.434285.317.1...472..8723549165..71.428.1428.537
I5: 5,8                                  # 18 pairs
* PAIR G4: 8,9 BLK 6
I5: 8,9,5,6                              # reduction candidate for 8,9
I5: 8,9                                  # 20 pairs
I6: 8,9,5,6                              # reduction candidate for 8,9
I6: 8,9                                  # 18 pairs
* PAIR G4: 8,9 ROW 4
A4: 8,9,6                                # reduction candidate for 8,9
A4: 8,9 => CTR
* 7914386..246975381385162794.57621.43428593176163847259.72354.1.5..71.4...1428.537
A4: 6 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
D4: 8,9,6                                # reduction candidate for 8,9
D4: 8,9 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
D4: 6 => CTR
* 7914386..246975381385162794.57621.43428593176163847259.72354.1.5..71.4...1428.537
* PAIR H6: 5,6 BLK 6
I5: 5,6,8,9                              # reduction candidate for 5,6
I5: 5,6                                  # 18 pairs
I6: 5,6,8,9                              # reduction candidate for 5,6
I6: 5,6                                  # 20 pairs
* PAIR H6: 5,6 ROW 6
D6: 5,6,8,9                              # reduction candidate for 5,6
D6: 5,6                                  # 20 pairs
D6: 8,9                                  # 17 pairs
* PAIR A9: 6,9 BLK 7
A7: 6,9,8                                # reduction candidate for 6,9
A7: 6,9 => CTR
* 7914386..24..753.13.51.27.485762194342..9317.1.9.472...7235481.5.371.4...1428.537
A7: 8                                    # 18 pairs
C8: 6,9,3,8                              # reduction candidate for 6,9
C8: 6,9 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
C8: 3,8                                  # 18 pairs
* PAIR A9: 6,9 COL A
A4: 6,9,8                                # reduction candidate for 6,9
A4: 8 => CTR
* 7914386..24..753.13.51.27.485762194342..9317.1.9.472...7235481.5.371.4...1428.537
A4: 6,9                                  # 18 pairs
* PAIR F8: 6,9 ROW 8
C8: 6,9,3,8                              # reduction candidate for 6,9
C8: 6,9 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
C8: 3,8                                  # 18 pairs
I8: 6,9,2,8                              # reduction candidate for 6,9
I8: 6,9 => CTR
* 79143865224..753.13.51.27.4857621943426.9317.139.4726..7235481.5.371.42..1428.537
I8: 2,8                                  # 18 pairs
* PAIR G7: 8,9 BLK 9
I7: 8,9,6                                # reduction candidate for 8,9
I7: 8,9 => CTR
* 7914386..24..753.13.51.27.485762194342..9317.1.9.472..6723548195.37194..914286537
I7: 6                                    # 15 pairs
I8: 8,9,2,6                              # reduction candidate for 8,9
I8: 8,9                                  # 15 pairs
* PAIR G7: 8,9 ROW 7
A7: 8,9,6                                # reduction candidate for 8,9
A7: 6 => CTR
* 7914386..24..753.13.51.27.485762194342..9317.1.9.472..6723548195.37194..914286537
A7: 8,9                                  # 15 pairs
* PAIR H8: 2,6 BLK 9
I8: 2,6,8,9                              # reduction candidate for 2,6
I8: 2,6 => CTR
* 7914386..24..753.13.51.27.485762194342..9317.1.9.472..6723548195.37194..914286537
I8: 8,9                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-090-base-pr-000.dot
* REASONING
* DIS # C6: 6,8 => CTR => C6: 3,9
* PRF # C8: 6,8 => SOL
* DIS # D5: 6,9 => CTR => D5: 5,8
* DIS # D6: 6,9 => CTR => D6: 5,8
* DIS # D5: 6,9 => CTR => D5: 5,8
* DIS # D6: 6,9 => CTR => D6: 5,8
* DIS # I5: 6,9 => CTR => I5: 5,8
* DIS # A4: 8,9 => CTR => A4: 6
* PRF # A4: 6 => SOL
* PRF # D4: 8,9 => SOL
* DIS # D4: 6 => CTR => D4: 8,9
* DIS # A7: 6,9 => CTR => A7: 8
* PRF # C8: 6,9 => SOL
* DIS # A4: 8 => CTR => A4: 6,9
* PRF # C8: 6,9 => SOL
* DIS # I8: 6,9 => CTR => I8: 2,8
* DIS # I7: 8,9 => CTR => I7: 6
* DIS # A7: 6 => CTR => A7: 8,9
* DIS # I8: 2,6 => CTR => I8: 8,9
* CNT  19 HDP CHAINS /  47 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B3,C2,D2,E3,E5,F8,F9,G4,G7,H1,H2,H3,H6,H8,I1)
* 7914386..24..753.13.51.27.4.57.21.4342...317.1...472...72354.1.5..71.4...1428.537
* PAIR C2: 6,8 COL C
C5: 6,8,9                                # reduction candidate for 6,8
C5: 6,8                                  # 19 pairs
C6: 6,8,3,9                              # reduction candidate for 6,8
C6: 6,8 => CTR
* 7914386..24.675391365192784657.21.43429.6317.138.472...72354.1.5.371.4...1428.537
C8: 6,8,3,9                              # reduction candidate for 6,8
C8: 6,8 => SOLVED
* 791438652248675391365192784657921843429863175183547269872354916536719428914286537
* DURATION: 0:00:03.967656  START: 05:53:07.388717  END: 05:53:11.356373 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-090-base-pr-001.dot
* REASONING
* DIS # C6: 6,8 => CTR => C6: 3,9
* PRF C6: 3,9 # C8: 6,8 => SOL
* STA C6: 3,9 + C8: 6,8
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 090

solution: 791438652248675391365192784657921843429863175183547269872354916536719428914286537
info: 1566     FNBTWXY  S8.f     36984

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

Solution

position: 791438652248675391365192784657921843429863175183547269872354916536719428914286537 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 # C5: 6,8 => UNS
* DIS # C6: 6,8 => CTR => C6: 3,9
* INC # C6: 3,9 => UNS
* PRF # C8: 6,8 => SOL
* INC # C8: 3,9 => UNS
* INC # B6: 6,8 => UNS
* INC # B8: 6,8 => UNS
* INC # D4: 6,9 => UNS
* DIS # D5: 6,9 => CTR => D5: 5,8
* INC # D5: 5,8 => UNS
* DIS # D6: 6,9 => CTR => D6: 5,8
* INC # D6: 5,8 => UNS
* INC # D4: 6,9 => UNS
* DIS # D5: 6,9 => CTR => D5: 5,8
* INC # D5: 5,8 => UNS
* DIS # D6: 6,9 => CTR => D6: 5,8
* INC # D6: 5,8 => UNS
* INC # C5: 6,9 => UNS
* DIS # I5: 6,9 => CTR => I5: 5,8
* INC # I5: 5,8 => UNS
* INC # I5: 8,9 => UNS
* INC # I6: 8,9 => UNS
* DIS # A4: 8,9 => CTR => A4: 6
* PRF # A4: 6 => SOL
* PRF # D4: 8,9 => SOL
* DIS # D4: 6 => CTR => D4: 8,9
* INC # I5: 5,6 => UNS
* INC # I6: 5,6 => UNS
* INC # D6: 5,6 => UNS
* INC # D6: 8,9 => UNS
* DIS # A7: 6,9 => CTR => A7: 8
* INC # A7: 8 => UNS
* PRF # C8: 6,9 => SOL
* INC # C8: 3,8 => UNS
* INC # A4: 6,9 => UNS
* DIS # A4: 8 => CTR => A4: 6,9
* PRF # C8: 6,9 => SOL
* INC # C8: 3,8 => UNS
* DIS # I8: 6,9 => CTR => I8: 2,8
* INC # I8: 2,8 => UNS
* DIS # I7: 8,9 => CTR => I7: 6
* INC # I7: 6 => UNS
* INC # I8: 8,9 => UNS
* INC # A7: 8,9 => UNS
* DIS # A7: 6 => CTR => A7: 8,9
* DIS # I8: 2,6 => CTR => I8: 8,9
* INC # I8: 8,9 => UNS
* CNT  47 HDP CHAINS /  47 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C5: 6,8 => UNS
* DIS # C6: 6,8 => CTR => C6: 3,9
* PRF C6: 3,9 # C8: 6,8 => SOL
* STA C6: 3,9 + C8: 6,8
* CNT   3 HDP CHAINS /   3 HYP OPENED