Rat in Maze problem in C++.

Author: rahulmandal4551

rat_maze.cpp

@@ -0,0 +1,80 @@
+/* C/C++ program to solve Rat in a Maze problem using 
+backtracking */
+#include<bits/stdc++.h>
+#define N 4
+using namespace std;
+/* A utility function to check if x, y is valid index for N*N maze */
+bool isSafe(int maze[N][N], int x, int y) 
+{
+	// if (x, y outside maze) return false 
+	if (x >= 0 && x < N && y >= 0 && y < N && maze[x][y] == 1)
+		return true;
+	return false;
+}
+/* This function solves the Maze problem using Backtracking. It mainly 
+uses solveMazeUtil() to solve the problem. It returns false if no 
+path is possible, otherwise return true and prints the path in the 
+form of 1s. Please note that there may be more than one solutions, 
+this function prints one of the feasible solutions.*/
+bool solveMazeUtil(int maze[N][N], int x, int y, int sol[N][N])
+{
+	// if (x, y is goal) return true 
+	if (x == N - 1 && 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;
+	}
+	return false;
+}
+/* A utility function to print solution matrix sol[N][N] */
+void printSolution(int sol[N][N])
+{ 
+	for (int i = 0; i < N; i++)
+	{ 
+		for (int j = 0; j < N; j++) 
+			cout << sol[i][j] << " "; 
+		cout << endl;
+	}
+}
+bool solveMaze(int maze[N][N]) 
+{
+	int sol[N][N] = { { 0, 0, 0, 0 },
+					{ 0, 0, 0, 0 },
+					{ 0, 0, 0, 0 },
+					{ 0, 0, 0, 0 } };
+	if (solveMazeUtil(maze, 0, 0, sol) == false)
+	{
+		cout << "Solution doesn't exist" << endl;;
+		return false;
+	}
+	printSolution(sol); 
+	return true;
+}
+/* A recursive utility function to solve Maze problem */
+// driver program to test above function
+int main()
+{
+	int maze[N][N] = { { 1, 0, 0, 0 },
+					{ 1, 1, 0, 1 },
+					{ 0, 1, 0, 0 },
+					{ 1, 1, 1, 1 } };
+	solveMaze(maze);
+	return 0;
+}