Create ratpath.java

ratpath.java

@@ -0,0 +1,82 @@
+import java.util.*;
+//In this code rat have to find shortest way to reach from starting corner to opposite ending corner which is shortest path to reach
+//applying recursion to solve it
+
+class Solution {
+
+    //applying recursion to solve this problem to choose shoertest way
+    public static void solve(int i,int j,int[][] a,int n,ArrayList<String> ans,String move,int[][]vis) {
+        //codition to terminate if i&j rech at boundary of matrix
+        if (i==n-1 && j==n-1){
+            ans.add(move);
+            return ;     
+        }
+
+        //D ->for down , R-> for right ,L -> for left , U -> for up 
+        //selecting shortest way to go by conditions
+
+        //if down-ward have 1 than move 
+        if (i+1<n && vis[i+1][j]==0 && a[i+1][j]==1 ){
+            vis[i][j] = 1;
+            solve(i+1, j, a, n, ans, move+"D", vis);
+            vis[i][j] = 0;
+        }
+        //if left side  have 1 than move 
+        if (j-1>0 && vis[i][j-1]==0 && a[i][j-1]==1 ){
+            vis[i][j] = 1;
+            solve(i, j-1, a, n, ans, move+"L", vis);
+            vis[i][j] = 0;
+        }
+        //if right side  have 1 than move   
+        if (j+1<n && vis[i][j+1]==0 && a[i][j+1]==1 ){
+            vis[i][j] = 1;
+            solve(i, j+1, a, n, ans, move+"R", vis);
+            vis[i][j] = 0;
+        }
+        //if up side have 1 than move
+        if (i-1>0 && vis[i-1][j]==0 && a[i-1][j]==1 ){
+            vis[i][j] = 1;
+            solve(i-1, j, a, n, ans, move+"U", vis);
+            vis[i][j] = 0;
+        }
+
+    }
+    //class to create a new matrix to add visite "1" or "0" not visite in main recive method
+    public static ArrayList<String> find(int[][] a,int n) {
+         int[] [] vis= new int[n][n];
+         for (int i=0;i<n;i++){
+            for (int j=0;j<n;j++){
+                vis[i][j] = 0;
+         }
+    }
+    //calling the solve method
+    ArrayList<String> ans = new ArrayList<>();
+    if (a[0][0] ==1) solve(0,0,a,n,ans,"",vis);
+    return ans;
+}
+}
+
+public class rat {
+    public static void main(String[] args) {
+        int n= 4;
+        // code take input in matrix form 
+        //which is in 0 or 1  and rat will decide what is the minimum rout to go at end corner 
+        //1 is for move and 0 is don't move
+
+        int[][] a={{1,0,0,0},{1,1,0,1},{1,1,0,0},{0,1,1,1}};
+        Solution obj=new Solution();
+        ArrayList<String> res=obj.find(a, n);
+
+        //print output in form of DRLU which is choice of rat to move in shortest way to reach at opposite corner
+        if(res.size()>0) {
+            for (int i=0; i<res.size(); i++) {
+                System.out.print(res.get(i)+" ");
+                System.out.println();
+            }
+        }else{
+            System.out.println(-1);
+        }
+        //output will be 2 because of same same shortest distance->
+        //DDRDRR and DRDDRR
+    }
+}