mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 13:31:07 +00:00
0b028aa32a
* Fix line break after binary operator
* fixup! Format Python code with psf/black push
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
116 lines
3.1 KiB
Python
116 lines
3.1 KiB
Python
def solve_maze(maze: list) -> bool:
|
|
"""
|
|
This method solves rat in maze algorithm.
|
|
In this problem we have n by n matrix and we have start point and end point
|
|
we want to go from source to distination. In this matrix 0 are block paths
|
|
1 are open paths we can use.
|
|
Parameters :
|
|
maze(2D matrix) : maze
|
|
Returns:
|
|
Return: True is maze has a solution or False if it does not.
|
|
>>> maze = [[0, 1, 0, 1, 1],
|
|
... [0, 0, 0, 0, 0],
|
|
... [1, 0, 1, 0, 1],
|
|
... [0, 0, 1, 0, 0],
|
|
... [1, 0, 0, 1, 0]]
|
|
>>> solve_maze(maze)
|
|
[1, 0, 0, 0, 0]
|
|
[1, 1, 1, 1, 0]
|
|
[0, 0, 0, 1, 0]
|
|
[0, 0, 0, 1, 1]
|
|
[0, 0, 0, 0, 1]
|
|
True
|
|
|
|
>>> maze = [[0, 1, 0, 1, 1],
|
|
... [0, 0, 0, 0, 0],
|
|
... [0, 0, 0, 0, 1],
|
|
... [0, 0, 0, 0, 0],
|
|
... [0, 0, 0, 0, 0]]
|
|
>>> solve_maze(maze)
|
|
[1, 0, 0, 0, 0]
|
|
[1, 0, 0, 0, 0]
|
|
[1, 0, 0, 0, 0]
|
|
[1, 0, 0, 0, 0]
|
|
[1, 1, 1, 1, 1]
|
|
True
|
|
|
|
>>> maze = [[0, 0, 0],
|
|
... [0, 1, 0],
|
|
... [1, 0, 0]]
|
|
>>> solve_maze(maze)
|
|
[1, 1, 1]
|
|
[0, 0, 1]
|
|
[0, 0, 1]
|
|
True
|
|
|
|
>>> maze = [[0, 1, 0],
|
|
... [0, 1, 0],
|
|
... [1, 0, 0]]
|
|
>>> solve_maze(maze)
|
|
Solution does not exists!
|
|
False
|
|
|
|
>>> maze = [[0, 1],
|
|
... [1, 0]]
|
|
>>> solve_maze(maze)
|
|
Solution does not exists!
|
|
False
|
|
"""
|
|
size = len(maze)
|
|
# We need to create solution object to save path.
|
|
solutions = [[0 for _ in range(size)] for _ in range(size)]
|
|
solved = run_maze(maze, 0, 0, solutions)
|
|
if solved:
|
|
print("\n".join(str(row) for row in solutions))
|
|
else:
|
|
print("Solution does not exists!")
|
|
return solved
|
|
|
|
|
|
def run_maze(maze, i, j, solutions):
|
|
"""
|
|
This method is recursive method which starts from i and j
|
|
and goes with 4 direction option up, down, left, right
|
|
if path found to destination it breaks and return True
|
|
otherwise False
|
|
Parameters:
|
|
maze(2D matrix) : maze
|
|
i, j : coordinates of matrix
|
|
solutions(2D matrix) : solutions
|
|
Returns:
|
|
Boolean if path is found True, Otherwise False.
|
|
"""
|
|
size = len(maze)
|
|
# Final check point.
|
|
if i == j == (size - 1):
|
|
solutions[i][j] = 1
|
|
return True
|
|
|
|
lower_flag = (not (i < 0)) and (not (j < 0)) # Check lower bounds
|
|
upper_flag = (i < size) and (j < size) # Check upper bounds
|
|
|
|
if lower_flag and upper_flag:
|
|
# check for already visited and block points.
|
|
block_flag = (not (solutions[i][j])) and (not (maze[i][j]))
|
|
if block_flag:
|
|
# check visited
|
|
solutions[i][j] = 1
|
|
|
|
# check for directions
|
|
if (
|
|
run_maze(maze, i + 1, j, solutions)
|
|
or run_maze(maze, i, j + 1, solutions)
|
|
or run_maze(maze, i - 1, j, solutions)
|
|
or run_maze(maze, i, j - 1, solutions)
|
|
):
|
|
return True
|
|
|
|
solutions[i][j] = 0
|
|
return False
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|