Merge pull request #120 from JASKAMAL22/rat_in_a_maze

Rat_in_a_Maze

Author: BeeBombshell

Backtracking/Rat_in_a_Maze.py

@@ -0,0 +1,69 @@
+# Maze size
+N = 4
+
+def printSolution( sol ):
+ 
+ for i in sol:
+ for j in i:
+ print(str(j) + " ", end ="")
+ print("")
+
+def isSafe( maze, x, y ):
+ if x >= 0 and x < N and y >= 0 and y < N and maze[x][y] == 1:
+ return True
+ 
+ return False
+ 
+def solveMaze( maze ):
+ # Creating a 4 * 4 2-D list
+ sol = [ [ 0 for j in range(4) ] for i in range(4) ]
+ 
+ if solveMazeUtil(maze, 0, 0, sol) == False:
+ print("Solution doesn't exist");
+ return False
+ printSolution(sol)
+ return True
+ 
+def solveMazeUtil(maze, x, y, sol):
+ # if (x, y is goal) return True
+ if x == N - 1 and y == N - 1:
+ sol[x][y] = 1
+ return True
+ 
+ # Check if maze[x][y] is valid
+ if isSafe(maze, x, y) == True:
+ # mark x, y as part of solution path
+ sol[x][y] = 1
+ 
+ # Move forward in x direction
+ if solveMazeUtil(maze, x + 1, y, sol) == True:
+ return True
+ 
+ # If moving in x direction doesn't give solution
+ # then Move down in y direction
+ if solveMazeUtil(maze, x, y + 1, sol) == True:
+ return True
+ 
+ # If none of the above movements work then
+ # BACKTRACK: unmark x, y as part of solution path
+ sol[x][y] = 0
+ return False
+ 
+# Main Program
+if __name__ == "__main__":
+ # Initialising the maze
+ maze = [ [1, 0, 0, 0],
+ [1, 1, 0, 1],
+ [0, 1, 0, 0],
+ [1, 1, 1, 1] ]
+ 
+ solveMaze(maze)
+''' 
+==============
+Output:
+1 0 0 0 
+1 1 0 0 
+0 1 0 0 
+0 1 1 1
+==============
+'''