Analysis of xx-top500-351-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 7..9...2...8.1.............9..2.7...2.....1........5...54...8.....7....3.1....... initial

Autosolve

position: 7..985.21598.127..1.2.7.9859.1257..82758.41..48.19.572.54.298178297.1.53.175.82.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B1: 3,6 => SOL
* PRF # G1: 4 => SOL
* PRF # D3: 3,6 => SOL
* PRF # B3: 4 => SOL
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # H2: 4,6 => CTR => H2: 3
* PRF # H2: 3 => SOL
* PRF # D2: 4,6 => SOL
* DIS # D2: 3 => CTR => D2: 4,6
* DIS # I9: 9 => CTR => I9: 4,6
* DIS # H4: 3,6 => CTR => H4: 4
* PRF # B1: 3,6 => SOL
* DIS # H5: 9 => CTR => H5: 3,6
* DIS # E9: 4 => CTR => E9: 3,6
* PRF # H5: 6,9 => SOL
* DIS # H5: 3 => CTR => H5: 6,9
* DIS # E9: 4 => CTR => E9: 3,6
* DIS # E9: 4 => CTR => E9: 3,6
* PRF # D3: 3,6 => SOL
* PRF # E9: 4,6 => SOL
* DIS # E9: 3 => CTR => E9: 4,6
* DIS # H9: 4,6 => CTR => H9: 9
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # G4: 4,6 => CTR => G4: 3
* PRF # G4: 3 => SOL
* CNT  27 HDP CHAINS /  48 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 # B1: 3,6 => SOL
* STA B1: 3,6
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

7..9...2...8.1.............9..2.7...2.....1........5...54...8.....7....3.1....... initial
7..985.21598.127..1.2.7.9859.1257..82758.41..48.19.572.54.298178297.1.53.175.82.. autosolve
736985421598412736142673985961257348275834169483196572654329817829741653317568294 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (13)
C1: 3,6
F3: 3,6
I2: 4,6
B4: 3,6
C6: 3,6
E5: 3,6
F6: 3,6
I5: 6,9
A7: 3,6
A9: 3,6
D7: 3,6
E8: 4,6
G8: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G1,H2: 3.. / G1 = 3  =>  0 pairs (X) / H2 = 3  =>  0 pairs (_)
B4,C6: 3.. / B4 = 3  =>  0 pairs (X) / C6 = 3  =>  0 pairs (_)
E5,F6: 3.. / E5 = 3  =>  0 pairs (*) / F6 = 3  =>  0 pairs (X)
A7,A9: 3.. / A7 = 3  =>  0 pairs (X) / A9 = 3  =>  0 pairs (_)
D7,E9: 3.. / D7 = 3  =>  0 pairs (*) / E9 = 3  =>  0 pairs (X)
D2,H2: 3.. / D2 = 3  =>  0 pairs (X) / H2 = 3  =>  0 pairs (_)
E5,H5: 3.. / E5 = 3  =>  0 pairs (*) / H5 = 3  =>  0 pairs (X)
C6,F6: 3.. / C6 = 3  =>  0 pairs (*) / F6 = 3  =>  0 pairs (X)
A7,D7: 3.. / A7 = 3  =>  0 pairs (X) / D7 = 3  =>  0 pairs (_)
A9,E9: 3.. / A9 = 3  =>  0 pairs (*) / E9 = 3  =>  0 pairs (X)
C1,C6: 3.. / C1 = 3  =>  0 pairs (X) / C6 = 3  =>  0 pairs (_)
E5,E9: 3.. / E5 = 3  =>  0 pairs (*) / E9 = 3  =>  0 pairs (X)
F3,F6: 3.. / F3 = 3  =>  0 pairs (*) / F6 = 3  =>  0 pairs (X)
G1,G4: 3.. / G1 = 3  =>  0 pairs (X) / G4 = 3  =>  0 pairs (_)
B1,B3: 4.. / B1 = 4  => 16 pairs (_) / B3 = 4  =>  0 pairs (*)
D2,D3: 4.. / D2 = 4  =>  0 pairs (*) / D3 = 4  =>  0 pairs (X)
G4,H4: 4.. / G4 = 4  =>  0 pairs (X) / H4 = 4  => 16 pairs (_)
E8,E9: 4.. / E8 = 4  => 18 pairs (_) / E9 = 4  =>  0 pairs (X)
B1,G1: 4.. / B1 = 4  => 16 pairs (_) / G1 = 4  =>  0 pairs (*)
B3,D3: 4.. / B3 = 4  =>  0 pairs (*) / D3 = 4  =>  0 pairs (X)
E8,G8: 4.. / E8 = 4  => 18 pairs (_) / G8 = 4  =>  0 pairs (X)
I2,I9: 4.. / I2 = 4  => 17 pairs (_) / I9 = 4  => 16 pairs (_)
B4,C6: 6.. / B4 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
E5,F6: 6.. / E5 = 6  =>  0 pairs (X) / F6 = 6  =>  0 pairs (_)
A7,A9: 6.. / A7 = 6  =>  0 pairs (*) / A9 = 6  =>  0 pairs (X)
C6,F6: 6.. / C6 = 6  =>  0 pairs (X) / F6 = 6  =>  0 pairs (_)
A7,D7: 6.. / A7 = 6  =>  0 pairs (*) / D7 = 6  =>  0 pairs (X)
E8,G8: 6.. / E8 = 6  =>  0 pairs (X) / G8 = 6  => 18 pairs (_)
C1,C6: 6.. / C1 = 6  =>  0 pairs (*) / C6 = 6  =>  0 pairs (X)
F3,F6: 6.. / F3 = 6  =>  0 pairs (X) / F6 = 6  =>  0 pairs (_)
H5,I5: 9.. / H5 = 9  =>  0 pairs (X) / I5 = 9  => 14 pairs (_)
H9,I9: 9.. / H9 = 9  => 14 pairs (_) / I9 = 9  =>  0 pairs (X)
H5,H9: 9.. / H5 = 9  =>  0 pairs (X) / H9 = 9  => 14 pairs (_)
I5,I9: 9.. / I5 = 9  => 14 pairs (_) / I9 = 9  =>  0 pairs (X)
* DURATION: 0:01:05.697630  START: 14:44:37.343660  END: 14:45:43.041290 2017-05-04
* CP COUNT: (34)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,A9,B4,C1,C6,D7,E5,E8,F3,F6,G8,I2,I5)
* 7..985.21598.127..1.2.7.9859.1257..82758.41..48.19.572.54.298178297.1.53.175.82..
* PAIR C1: 3,6 BLK 1
B1: 3,6,4                                # reduction candidate for 3,6
B1: 3,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
B1: 4                                    # 16 pairs
B3: 3,6,4                                # reduction candidate for 3,6
B3: 3,6                                  # 16 pairs
* PAIR C1: 3,6 ROW 1
G1: 3,6,4                                # reduction candidate for 3,6
G1: 4 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
G1: 3,6                                  # 16 pairs
* PAIR F3: 3,6 BLK 2
D2: 3,6,4                                # reduction candidate for 3,6
D2: 3,6                                  # 16 pairs
D3: 3,6,4                                # reduction candidate for 3,6
D3: 3,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
D3: 4                                    # 16 pairs
* PAIR F3: 3,6 ROW 3
B3: 3,6,4                                # reduction candidate for 3,6
B3: 4 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
B3: 3,6                                  # 16 pairs
* PAIR I2: 4,6 BLK 3
G1: 4,6,3                                # reduction candidate for 4,6
G1: 4,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
G1: 3 => CTR
* 7469853215983127..1324769859.1257..82758.41..48.19.572.54.298178297.1.53.175.82..
H2: 4,6,3                                # reduction candidate for 4,6
H2: 4,6 => CTR
* 7..9853215983127..132476985961257..82758.41..48.19.572.54.298178297.1.53.175.82..
H2: 3 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
* PAIR I2: 4,6 ROW 2
D2: 4,6,3                                # reduction candidate for 4,6
D2: 4,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
D2: 3 => CTR
* 7..985.215983127..132476985961257..82758.41..48.19.572.54.298178297.1.53.175.82..
* PAIR I2: 4,6 COL I
I9: 4,6,9                                # reduction candidate for 4,6
I9: 9 => CTR
* 746985321598.127.41.247.9859.1257..82758.41.648.196572.54.298178297.1.53.175.82.9
I9: 4,6                                  # 14 pairs
* PAIR B4: 3,6 ROW 4
G4: 3,6,4                                # reduction candidate for 3,6
G4: 3,6                                  # 16 pairs
H4: 3,6,4                                # reduction candidate for 3,6
H4: 3,6 => CTR
* 7469853215983127..1324769859.12574.82758.41..48.19.572.54.29817829741653.175.82..
H4: 4                                    # 16 pairs
* PAIR B4: 3,6 COL B
B1: 3,6,4                                # reduction candidate for 3,6
B1: 3,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
B1: 4                                    # 16 pairs
B3: 3,6,4                                # reduction candidate for 3,6
B3: 3,6                                  # 16 pairs
* PAIR E5: 3,6 ROW 5
H5: 3,6,9                                # reduction candidate for 3,6
H5: 9 => CTR
* 7.6985.21598.127..1.2.7.9859.1257..8275834196483196572.543298178297.1.533175.82.9
H5: 3,6                                  # 14 pairs
* PAIR E5: 3,6 COL E
E9: 3,6,4                                # reduction candidate for 3,6
E9: 4 => CTR
* 746985321598.127.4132.7.9859.1257..82758341..483196572.543298178297614533175482..
E9: 3,6                                  # 18 pairs
* PAIR I5: 6,9 BLK 6
H5: 6,9,3                                # reduction candidate for 6,9
H5: 6,9 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
H5: 3 => CTR
* 7.3985.215983127461.2.7.9859.1257..82758.413948.193572.54.298178297.1.53.17538294
* PAIR I5: 6,9 COL I
I9: 6,9,4                                # reduction candidate for 6,9
I9: 6,9                                  # 17 pairs
I9: 4                                    # 16 pairs
* PAIR A9: 3,6 ROW 9
E9: 3,6,4                                # reduction candidate for 3,6
E9: 4 => CTR
* 746985321598.127.4132.7.9859.1257..82758341..483196572.543298178297614533175482..
E9: 3,6                                  # 18 pairs
* PAIR D7: 3,6 BLK 8
E9: 3,6,4                                # reduction candidate for 3,6
E9: 4 => CTR
* 746985321598.127.4132.7.9859.1257..82758341..483196572.543298178297614533175482..
E9: 3,6                                  # 18 pairs
* PAIR D7: 3,6 COL D
D2: 3,6,4                                # reduction candidate for 3,6
D2: 3,6                                  # 16 pairs
D3: 3,6,4                                # reduction candidate for 3,6
D3: 3,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
D3: 4                                    # 16 pairs
* PAIR E8: 4,6 BLK 8
E9: 4,6,3                                # reduction candidate for 4,6
E9: 4,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
E9: 3 => CTR
* 763985.21598.127..1.2.7.9859.1257..8275864139486193572354629817829741653617538294
* PAIR G8: 4,6 BLK 9
H9: 4,6,9                                # reduction candidate for 4,6
H9: 4,6 => CTR
* 7.6985.21598.127641.2.7.9859.1257..82758.419648.196572.54.298178297.1.53.175.82.9
H9: 9                                    # 14 pairs
I9: 4,6,9                                # reduction candidate for 4,6
I9: 4,6                                  # 14 pairs
* PAIR G8: 4,6 COL G
G1: 4,6,3                                # reduction candidate for 4,6
G1: 4,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
G1: 3 => CTR
* 7469853215983127..1324769859.1257..82758.41..48.19.572.54.298178297.1.53.175.82..
G4: 4,6,3                                # reduction candidate for 4,6
G4: 4,6 => CTR
* 7..9853215983127..132476985961257..82758.41..48.19.572.54.298178297.1.53.175.82..
G4: 3 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-351-base-pr-000.dot
* REASONING
* PRF # B1: 3,6 => SOL
* PRF # G1: 4 => SOL
* PRF # D3: 3,6 => SOL
* PRF # B3: 4 => SOL
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # H2: 4,6 => CTR => H2: 3
* PRF # H2: 3 => SOL
* PRF # D2: 4,6 => SOL
* DIS # D2: 3 => CTR => D2: 4,6
* DIS # I9: 9 => CTR => I9: 4,6
* DIS # H4: 3,6 => CTR => H4: 4
* PRF # B1: 3,6 => SOL
* DIS # H5: 9 => CTR => H5: 3,6
* DIS # E9: 4 => CTR => E9: 3,6
* PRF # H5: 6,9 => SOL
* DIS # H5: 3 => CTR => H5: 6,9
* DIS # E9: 4 => CTR => E9: 3,6
* DIS # E9: 4 => CTR => E9: 3,6
* PRF # D3: 3,6 => SOL
* PRF # E9: 4,6 => SOL
* DIS # E9: 3 => CTR => E9: 4,6
* DIS # H9: 4,6 => CTR => H9: 9
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # G4: 4,6 => CTR => G4: 3
* PRF # G4: 3 => SOL
* CNT  27 HDP CHAINS /  48 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,A9,B4,C1,C6,D7,E5,E8,F3,F6,G8,I2,I5)
* 7..985.21598.127..1.2.7.9859.1257..82758.41..48.19.572.54.298178297.1.53.175.82..
* PAIR C1: 3,6 BLK 1
B1: 3,6,4                                # reduction candidate for 3,6
B1: 3,6 => SOLVED
* 736985421598412736142673985961257348275834169483196572654329817829741653317568294
* DURATION: 0:00:02.126665  START: 14:46:40.048071  END: 14:46:42.174736 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-351-base-pr-001.dot
* REASONING
* PRF # B1: 3,6 => SOL
* STA B1: 3,6
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 351

solution: 736985421598412736142673985961257348275834169483196572654329817829741653317568294
info: 4883     FNBWX    S8.f     37164

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

Solution

position: 736985421598412736142673985961257348275834169483196572654329817829741653317568294 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:

* PRF # B1: 3,6 => SOL
* INC # B1: 4 => UNS
* INC # B3: 3,6 => UNS
* INC # G1: 3,6 => UNS
* PRF # G1: 4 => SOL
* INC # D2: 3,6 => UNS
* PRF # D3: 3,6 => SOL
* INC # D3: 4 => UNS
* INC # B3: 3,6 => UNS
* PRF # B3: 4 => SOL
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # H2: 4,6 => CTR => H2: 3
* PRF # H2: 3 => SOL
* PRF # D2: 4,6 => SOL
* DIS # D2: 3 => CTR => D2: 4,6
* INC # I9: 4,6 => UNS
* DIS # I9: 9 => CTR => I9: 4,6
* INC # G4: 3,6 => UNS
* DIS # H4: 3,6 => CTR => H4: 4
* INC # H4: 4 => UNS
* PRF # B1: 3,6 => SOL
* INC # B1: 4 => UNS
* INC # B3: 3,6 => UNS
* INC # H5: 3,6 => UNS
* DIS # H5: 9 => CTR => H5: 3,6
* INC # E9: 3,6 => UNS
* DIS # E9: 4 => CTR => E9: 3,6
* PRF # H5: 6,9 => SOL
* DIS # H5: 3 => CTR => H5: 6,9
* INC # I9: 6,9 => UNS
* INC # I9: 4 => UNS
* INC # E9: 3,6 => UNS
* DIS # E9: 4 => CTR => E9: 3,6
* INC # E9: 3,6 => UNS
* DIS # E9: 4 => CTR => E9: 3,6
* INC # D2: 3,6 => UNS
* PRF # D3: 3,6 => SOL
* INC # D3: 4 => UNS
* PRF # E9: 4,6 => SOL
* DIS # E9: 3 => CTR => E9: 4,6
* DIS # H9: 4,6 => CTR => H9: 9
* INC # H9: 9 => UNS
* INC # I9: 4,6 => UNS
* PRF # G1: 4,6 => SOL
* DIS # G1: 3 => CTR => G1: 4,6
* DIS # G4: 4,6 => CTR => G4: 3
* PRF # G4: 3 => SOL
* CNT  48 HDP CHAINS /  48 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # B1: 3,6 => SOL
* STA B1: 3,6
* CNT   1 HDP CHAINS /   1 HYP OPENED