8 Puzzle Jupyter Code

%load_ext autoreload
%autoreload 2
from eightpuzzle import *

Checking for Goal States

# These are not goal states
s = State([[1, 4, 2], [3, 7, " "], [6, 8, 5]])
print(s.is_goal())
print(s)

s = State([[2, 6, 1], [7, " ", 3], [5, 8, 4]])
print(s.is_goal())
print(s)

# These are goal states
s = State([[1, 2, 3], [4, " ", 5], [6, 7, 8]])
print(s.is_goal())
print(s)

s = State([[" ", 1, 2], [3, 4, 5], [6, 7, 8]])
print(s.is_goal())
print(s)

False
1 4 2 
3 7   
6 8 5 

False
2 6 1 
7   3 
5 8 4 

True
1 2 3 
4   5 
6 7 8 

True
  1 2 
3 4 5 
6 7 8 

Getting Neighbors

s = State([[1, 2, 3], [4, " ", 5], [6, 7, 8]])
print(s)
for n in s.get_neighbs():
    print(n)

1 2 3 
4   5 
6 7 8 

1   3 
4 2 5 
6 7 8 

1 2 3 
4 7 5 
6   8 

1 2 3 
  4 5 
6 7 8 

1 2 3 
4 5   
6 7 8 

Solving Puzzles

Here's a fairly easy puzzle that can be solved with tree search

s = State([[1, 4, 2], [3, 7, " "], [6, 8, 5]])
for step in s.solve():
    print(step)

Expanded:  67
1 4 2 
3 7   
6 8 5 

1 4 2 
3 7 5 
6 8   

1 4 2 
3 7 5 
6   8 

1 4 2 
3   5 
6 7 8 

1   2 
3 4 5 
6 7 8 

Here's a harder puzzle that needs graph search

s = State([[2, 6, 1], [7, " ", 3], [5, 8, 4]])
for step in s.solve():
    print(step)

Expanded:  51274
2 6 1 
7   3 
5 8 4 

2 6 1 
7 3   
5 8 4 

2 6   
7 3 1 
5 8 4 

2   6 
7 3 1 
5 8 4 

2 3 6 
7   1 
5 8 4 

2 3 6 
7 1   
5 8 4 

2 3 6 
7 1 4 
5 8   

2 3 6 
7 1 4 
5   8 

2 3 6 
7 1 4 
  5 8 

2 3 6 
  1 4 
7 5 8 

2 3 6 
1   4 
7 5 8 

2 3 6 
1 4   
7 5 8 

2 3   
1 4 6 
7 5 8 

2   3 
1 4 6 
7 5 8 

  2 3 
1 4 6 
7 5 8 

1 2 3 
  4 6 
7 5 8 

1 2 3 
4   6 
7 5 8 

1 2 3 
4 5 6 
7   8