Rat in a Maze Backtracking Problem

#1

https://practice.geeksforgeeks.org/problems/rat-in-a-maze-problem/1#

Please check out above link and tell me why cases are getting failed even it is running in my intellij Idea
My solution is given below:

class Solution {
static ArrayList res = new ArrayList<>();
public static ArrayList findPath(int[][] m, int n) {
// Your code here
mazePath(m, 0, 0, “”);
return res;
}

public static void mazePath(int[][] m, int row, int col, String ans) {
    if(row < 0 || col < 0 || row >= m.length || col >= m[0].length || m[row][col] == 0) {
        return;
    }
    if(row == m.length-1 && col == m.length-1) {
        res.add(ans);
        return;
    }
    
    m[row][col] = 0;
    // U
    mazePath(m, row-1, col, ans + "U");
    // R
    mazePath(m, row, col+1, ans + "R");
    // D
    mazePath(m, row+1, col, ans + "D");
    // L
    mazePath(m, row, col-1, ans + "L");
    m[row][col] = 1;
}

}

#2

Hey @danishrehman288 You are getting duplicate answers bcoz you have initiated the ArrayList globally which means everytime a function is called changes will be made but previous element which are already present in arraylist will also be there(means wrong answers). I have changed your code : (Changes are made in the array list initialization and first line of findpath method.) the concept is I will reinitialize the array list everytime to prevent storage of prev answers.

class Solution {
    static ArrayList<String> res;
    public static ArrayList<String> findPath(int[][] m, int n) {
        // Your code here
        res = new ArrayList<>();
        mazePath(m, 0, 0, "");
      return res;
    }
    public static void mazePath(int[][] m, int row, int col, String ans) {
    if(row < 0 || col < 0 || row >= m.length || col >= m[0].length || m[row][col] == 0) {
        return;
    }
    if(row == m.length-1 && col == m.length-1) {
        res.add(ans);
        return;
    }
    
    m[row][col] = 0;
    // U
    mazePath(m, row-1, col, ans + "U");
    // R
    mazePath(m, row, col+1, ans + "R");
    // D
    mazePath(m, row+1, col, ans + "D");
    // L
    mazePath(m, row, col-1, ans + "L");
    m[row][col] = 1;
}
}
#3

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