Analysis of xx-top95-050-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 6..3.2....1.....5..........7.26............843.........8.15........8.2........7.. initial

Autosolve

position: 6..3.28...1.....52.2.......7.26.8..........843.8....2728.15........8.2.5......7.8 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # I3: 1,9 => CTR => I3: 3,6
* DIS # E1: 4,7 => CTR => E1: 1,9
* DIS # I4: 3 => CTR => I4: 1,9
* DIS # G4: 3,9 => CTR => G4: 1,5
* DIS # I4: 3,9 => CTR => I4: 1
* DIS # E4: 1,4 => CTR => E4: 3,9
* PRF # H3: 3,9 => SOL
* CNT   7 HDP CHAINS /  19 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 # I3: 1,9 => CTR => I3: 3,6
* DIS I3: 3,6 # G3: 3,4 => CTR => G3: 1,9
* DIS I3: 3,6 + G3: 1,9 # E1: 4,7 => CTR => E1: 1,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 # I4: 3 => CTR => I4: 1,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 # G4: 3,9 => CTR => G4: 1,5
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 # G5: 5,6 => CTR => G5: 3,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 # E4: 4 => CTR => E4: 3,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # C1: 5,7 => CTR => C1: 4
* PRF I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4 => SOL
* STA I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4
* CNT   9 HDP CHAINS /  21 HYP OPENED

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

Details

Positions

6..3.2....1.....5..........7.26............843.........8.15........8.2........7.. initial
6..3.28...1.....52.2.......7.26.8..........843.8....2728.15........8.2.5......7.8 autosolve
654312879913876452827495136742638591165729384398541627286157943471983265539264718 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (2)
I1: 1,9
H4: 3,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A5,C5: 1.. / A5 = 1  =>  3 pairs (_) / C5 = 1  =>  3 pairs (_)
H8,H9: 1.. / H8 = 1  =>  5 pairs (_) / H9 = 1  =>  2 pairs (_)
E1,I1: 1.. / E1 = 1  =>  7 pairs (_) / I1 = 1  =>  0 pairs (X)
F3,F6: 1.. / F3 = 1  =>  0 pairs (X) / F6 = 1  =>  3 pairs (_)
D5,E5: 2.. / D5 = 2  =>  3 pairs (_) / E5 = 2  =>  2 pairs (_)
D9,E9: 2.. / D9 = 2  =>  2 pairs (_) / E9 = 2  =>  3 pairs (_)
D5,D9: 2.. / D5 = 2  =>  3 pairs (_) / D9 = 2  =>  2 pairs (_)
E5,E9: 2.. / E5 = 2  =>  2 pairs (_) / E9 = 2  =>  3 pairs (_)
C2,C3: 3.. / C2 = 3  =>  0 pairs (*) / C3 = 3  =>  0 pairs (X)
B8,B9: 3.. / B8 = 3  =>  0 pairs (X) / B9 = 3  =>  2 pairs (_)
C2,G2: 3.. / C2 = 3  =>  0 pairs (*) / G2 = 3  =>  0 pairs (X)
B4,B6: 4.. / B4 = 4  =>  2 pairs (_) / B6 = 4  =>  0 pairs (X)
B4,E4: 4.. / B4 = 4  =>  2 pairs (_) / E4 = 4  =>  0 pairs (X)
B1,C1: 5.. / B1 = 5  =>  0 pairs (*) / C1 = 5  =>  0 pairs (X)
D3,F3: 5.. / D3 = 5  =>  4 pairs (_) / F3 = 5  =>  3 pairs (_)
B4,G4: 5.. / B4 = 5  =>  0 pairs (X) / G4 = 5  =>  3 pairs (_)
A5,A9: 5.. / A5 = 5  =>  9 pairs (_) / A9 = 5  =>  3 pairs (_)
E2,F2: 6.. / E2 = 6  =>  2 pairs (_) / F2 = 6  =>  0 pairs (*)
H3,I3: 6.. / H3 = 6  =>  0 pairs (X) / I3 = 6  =>  3 pairs (_)
G5,G6: 6.. / G5 = 6  =>  0 pairs (X) / G6 = 6  =>  2 pairs (_)
B6,G6: 6.. / B6 = 6  =>  0 pairs (X) / G6 = 6  =>  2 pairs (_)
E2,E9: 6.. / E2 = 6  =>  2 pairs (_) / E9 = 6  =>  0 pairs (*)
I3,I7: 6.. / I3 = 6  =>  3 pairs (_) / I7 = 6  =>  0 pairs (X)
H1,H3: 7.. / H1 = 7  =>  0 pairs (*) / H3 = 7  =>  0 pairs (X)
C7,F7: 7.. / C7 = 7  =>  0 pairs (X) / F7 = 7  =>  5 pairs (_)
B1,B8: 7.. / B1 = 7  =>  0 pairs (X) / B8 = 7  =>  0 pairs (_)
A2,A3: 8.. / A2 = 8  =>  4 pairs (_) / A3 = 8  =>  3 pairs (_)
D2,D3: 8.. / D2 = 8  =>  3 pairs (_) / D3 = 8  =>  4 pairs (_)
A2,D2: 8.. / A2 = 8  =>  4 pairs (_) / D2 = 8  =>  3 pairs (_)
A3,D3: 8.. / A3 = 8  =>  3 pairs (_) / D3 = 8  =>  4 pairs (_)
* DURATION: 0:00:43.102873  START: 23:52:02.584777  END: 23:52:45.687650 2017-05-03
* CP COUNT: (30)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (H4,I1)
* 6..3.28...1.....52.2.......7.26.8..........843.8....2728.15........8.2.5......7.8
* PAIR I1: 1,9 BLK 3
G3: 1,9,3,4                              # reduction candidate for 1,9
G3: 1,9                                  #  6 pairs
I3: 1,9,3,6                              # reduction candidate for 1,9
I3: 1,9 => CTR
* 6..3.287..1.....52.2.....6.7.26.8.93....3..843.8....2728.157936.7..832.5.3..267.8
I3: 3,6                                  #  3 pairs
* PAIR I1: 1,9 ROW 1
E1: 1,9,4,7                              # reduction candidate for 1,9
E1: 4,7 => CTR
* 6..3.28.1.17.6.352.23......7.26.8..........843.8....2728.157....7..8.2.5.3..2.7.8
E1: 1,9                                  #  5 pairs
* PAIR I1: 1,9 COL I
I4: 1,9,3                                # reduction candidate for 1,9
I4: 3 => CTR
* 6..3.28...17.6.352.23......7.26.8.93.......843.8....2728.157.3..7..832.5......7.8
I4: 1,9                                  #  5 pairs
* PAIR H4: 3,9 BLK 6
G4: 3,9,1,5                              # reduction candidate for 3,9
G4: 3,9 => CTR
* 6.5312849.1....352.23...176752648931......584348.9.62728.15........8.2.55.....7.8
G4: 1,5                                  #  3 pairs
I4: 3,9,1                                # reduction candidate for 3,9
I4: 3,9 => CTR
* 6..3.28...17.6.352.23......7.26.8..........843.8....2728.157....7..8.2.5.3..2.7.8
I4: 1                                    #  7 pairs
G5: 3,9,5,6                              # reduction candidate for 3,9
G5: 3,9                                  #  9 pairs
* PAIR H4: 3,9 ROW 4
E4: 3,9,1,4                              # reduction candidate for 3,9
E4: 1,4 => CTR
* 6..3.28...17.6.352.23......7.26.8..........843.8....2728.157....7..8.2.5.3..2.7.8
E4: 3,9                                  #  9 pairs
* PAIR H4: 3,9 COL H
H3: 3,9,4,6,7                            # reduction candidate for 3,9
H3: 3,9 => SOLVED
* 654312879913876452827495136742638591165729384398541627286157943471983265539264718
H3: 4,6,7                                #  2 pairs
H7: 3,9,4,6                              # reduction candidate for 3,9
H7: 3,9                                  #  4 pairs
H8: 3,9,1,4,6                            # reduction candidate for 3,9
H8: 3,9                                  #  6 pairs
H9: 3,9,1,4,6                            # reduction candidate for 3,9
H9: 3,9                                  #  9 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-050-base-pr-000.dot
* REASONING
* DIS # I3: 1,9 => CTR => I3: 3,6
* DIS # E1: 4,7 => CTR => E1: 1,9
* DIS # I4: 3 => CTR => I4: 1,9
* DIS # G4: 3,9 => CTR => G4: 1,5
* DIS # I4: 3,9 => CTR => I4: 1
* DIS # E4: 1,4 => CTR => E4: 3,9
* PRF # H3: 3,9 => SOL
* CNT   7 HDP CHAINS /  19 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (H4,I1)
* 6..3.28...1.....52.2.......7.26.8..........843.8....2728.15........8.2.5......7.8
* PAIR I1: 1,9 BLK 3
G3: 1,9,3,4                              # reduction candidate for 1,9
G3: 1,9                                  #  6 pairs
I3: 1,9,3,6                              # reduction candidate for 1,9
I3: 1,9 => CTR
* 6..3.287..1.....52.2.....6.7.26.8.93....3..843.8....2728.157936.7..832.5.3..267.8
* RESTART
* PAIR I1: 1,9 BLK 3
G3: 1,9,3,4                              # reduction candidate for 1,9
G3: 3,4 => CTR
* 6..3.28.1.17.6.352.23...4.67.26.8..........843.8....2728.1579.3.7..832.5......7.8
* PAIR I1: 1,9 ROW 1
E1: 1,9,4,7                              # reduction candidate for 1,9
E1: 4,7 => CTR
* 6..3.28.1.1..6..52.2....9..7.26.8..........843.8.9..2728.157....7..8.2.5.3..2.7.8
* PAIR I1: 1,9 COL I
I4: 1,9,3                                # reduction candidate for 1,9
I4: 3 => CTR
* 6..392871.17.64352.235719467.26.8.93.......843.89.5.2728.157439.7.4832.5......7.8
* PAIR RESTART
* PAIR H4: 3,9 BLK 6
G4: 3,9,1,5                              # reduction candidate for 3,9
G4: 3,9 => CTR
* 675312849.1....352.23...176752648931......584348.9.62728.15........8.2.55.....7.8
G5: 3,9,5,6                              # reduction candidate for 3,9
G5: 3,9                                  #  9 pairs
* RESTART
* PAIR H4: 3,9 BLK 6
G5: 3,9,5,6                              # reduction candidate for 3,9
G5: 5,6 => CTR
* 6..3.287..17.6.352.23.7..467.26.8.3........843.8....2728.1574.3.7..832.5......7.8
* PAIR H4: 3,9 ROW 4
E4: 3,9,4                                # reduction candidate for 3,9
E4: 4 => CTR
* 6..312879.17.6.352.23.75146792648531......98434859162728.1574.3.7..832.5......7.8
* PAIR H4: 3,9 COL H
H7: 3,9,4,6                              # reduction candidate for 3,9
H7: 3,9                                  # 11 pairs
H8: 3,9,1,4,6                            # reduction candidate for 3,9
H8: 3,9                                  # 13 pairs
H9: 3,9,1,4,6                            # reduction candidate for 3,9
H9: 3,9                                  # 16 pairs
* PAIR RESTART
* PAIR H4: 3,9 COL H
H7: 3,9,4,6                              # reduction candidate for 3,9
H7: 3,9                                  # 11 pairs
H8: 3,9,1,4,6                            # reduction candidate for 3,9
H8: 3,9                                  # 13 pairs
H9: 3,9,1,4,6                            # reduction candidate for 3,9
H9: 3,9                                  # 16 pairs

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (B1,B6,E4,E6,G2,G5,H1,H4,I3,I7)
* 6..3128.9.1.....52.2....1..7426.85.1.......843.8..162728.15........8.2.5......7.8
* PAIR B1: 5,7 BLK 1
C1: 5,7,4                                # reduction candidate for 5,7
C1: 5,7 => CTR
* 6..312849.1....352.23...1767426.8531......98439854162728.15.4.3....8.2.5......7.8
C1: 4 => SOLVED
* 654312879913876452827495136742638591165729384398541627286157943471983265539264718
* DURATION: 0:00:22.030724  START: 23:53:00.663311  END: 23:53:22.694035 2017-05-03
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-050-base-pr-001.dot
* REASONING
* DIS # I3: 1,9 => CTR => I3: 3,6
* DIS I3: 3,6 # G3: 3,4 => CTR => G3: 1,9
* DIS I3: 3,6 + G3: 1,9 # E1: 4,7 => CTR => E1: 1,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 # I4: 3 => CTR => I4: 1,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 # G4: 3,9 => CTR => G4: 1,5
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 # G5: 5,6 => CTR => G5: 3,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 # E4: 4 => CTR => E4: 3,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # C1: 5,7 => CTR => C1: 4
* PRF I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4 => SOL
* STA I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4
* CNT   9 HDP CHAINS /  21 HYP OPENED

Header Info

Top 95 Sudokus 050
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 654312879913876452827495136742638591165729384398541627286157943471983265539264718 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 # G3: 1,9 => UNS
* DIS # I3: 1,9 => CTR => I3: 3,6
* INC # I3: 3,6 => UNS
* INC # E1: 1,9 => UNS
* DIS # E1: 4,7 => CTR => E1: 1,9
* INC # I4: 1,9 => UNS
* DIS # I4: 3 => CTR => I4: 1,9
* DIS # G4: 3,9 => CTR => G4: 1,5
* INC # G4: 1,5 => UNS
* DIS # I4: 3,9 => CTR => I4: 1
* INC # I4: 1 => UNS
* INC # G5: 3,9 => UNS
* INC # E4: 3,9 => UNS
* DIS # E4: 1,4 => CTR => E4: 3,9
* PRF # H3: 3,9 => SOL
* INC # H3: 4,6,7 => UNS
* INC # H7: 3,9 => UNS
* INC # H8: 3,9 => UNS
* INC # H9: 3,9 => UNS
* CNT  19 HDP CHAINS /  19 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # G3: 1,9 => UNS
* DIS # I3: 1,9 => CTR => I3: 3,6
* INC I3: 3,6 # G3: 1,9 => UNS
* DIS I3: 3,6 # G3: 3,4 => CTR => G3: 1,9
* INC I3: 3,6 + G3: 1,9 # E1: 1,9 => UNS
* DIS I3: 3,6 + G3: 1,9 # E1: 4,7 => CTR => E1: 1,9
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 # I4: 1,9 => UNS
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 # I4: 3 => CTR => I4: 1,9
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 # G4: 3,9 => CTR => G4: 1,5
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 # G5: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 # G5: 3,9 => UNS
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 # G5: 5,6 => CTR => G5: 3,9
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 # E4: 3,9 => UNS
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 # E4: 4 => CTR => E4: 3,9
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H7: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H8: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H9: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H7: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H8: 3,9 => UNS
* INC I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # H9: 3,9 => UNS
* DIS I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 # C1: 5,7 => CTR => C1: 4
* PRF I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4 => SOL
* STA I3: 3,6 + G3: 1,9 + E1: 1,9 + I4: 1,9 + G4: 1,5 + G5: 3,9 + E4: 3,9 + C1: 4
* CNT  22 HDP CHAINS /  21 HYP OPENED