Create RatInAMaze.py

backtracking/RatInAMaze.py

@@ -0,0 +1,70 @@
+class Solution:
+    def __init__(self):
+        # Initialize a string direction which represents all the directions.
+        self.direction = "DLRU"
+        # Arrays to represent changes in rows and columns
+        self.dr = [1, 0, 0, -1]
+        self.dc = [0, -1, 1, 0]
+
+    # Function to check if cell (r, c) is inside the maze and unblocked
+    def is_valid(self, r, c, n, maze):
+        return 0 <= r < n and 0 <= c < n and maze[r] == 1
+
+    # Function to get all valid paths
+    def solve(self, r, c, maze, n, ans, current_path):
+        # If we reach the bottom right cell of the matrix, add the current path to ans and return
+        if r == n - 1 and c == n - 1:
+            ans.append(current_path)
+            return
+
+        # Mark the current cell as blocked
+        maze[r] = 0
+
+        for i in range(4):
+            # Find the next row based on the current row (r) and the dr[] array
+            nextr = r + self.dr[i]
+            # Find the next column based on the current column (c) and the dc[] array
+            nextc = c + self.dc[i]
+
+            # Check if the next cell is valid or not
+            if self.is_valid(nextr, nextc, n, maze):
+                current_path += self.direction[i]
+                # Recursively call the solve function for the next cell
+                self.solve(nextr, nextc, maze, n, ans, current_path)
+                current_path = current_path[:-1]
+
+        # Mark the current cell as unblocked
+        maze[r] = 1
+
+    def find_path(self, maze, n):
+        # List to store all the valid paths
+        ans = []
+
+        # Check if the top left cell is unblocked
+        if maze[0][0] == 1:
+            current_path = ""
+            self.solve(0, 0, maze, n, ans, current_path)
+        return ans
+
+
+# Main function
+
+
+def main():
+    n = 4
+
+    m = [[1, 0, 0, 0], [1, 1, 0, 1], [1, 1, 0, 0], [0, 1, 1, 1]]
+
+    obj = Solution()
+    result = obj.find_path(m, n)
+
+    if not result:
+        print(-1)
+    else:
+        for path in result:
+            print(path, end=" ")
+        print()
+
+
+if __name__ == "__main__":
+    main()