lec40_rec10_ratinamaze.cpp

//{ Driver Code Starts
// Initial template for C++

#include <bits/stdc++.h>
using namespace std;


// } Driver Code Ends
// User function template for C++

class Solution{
    private:
    
    bool isSafe(int x,int y,int n,vector<vector<int>> visited, vector<vector<int>> m)
    {
        if((x>=0&&x<n)&&(y>=0&&y<n)&&(visited[x][y]==0)&&(m[x][y]==1))
        {
            return 0;
        }
        else
        return 1;
    }
    
    
    
    
void solve(vector<vector<int>> m,int n, vector <string> &ans,int x, int y,vector<vector<int>> visited, string path)
{
//base case       // reached END
    if(x==n-1 && y==n-1){
        ans.push_back(path);
        return ;
    }
    
    
    visited[x][y]=1;
    
    //4 choices= D L R U
    
    //down
    int newx= x+1;
    int newy=y;
    if(isSafe(newx,newy,n,visited,m))
    {
        path.push_back('D');
        solve(m,n,ans,newx,newy,visited,path);
        path.pop_back();
    }
    //left
    newx= x;
    newy=y-1;
    if(isSafe(newx,newy,n,visited,m))
    {
        path.push_back('L');
        solve(m,n,ans,newx,newy,visited,path);
        path.pop_back();
    }
    //right
    newx= x;
    newy=y+1;
    if(isSafe(newx,newy,n,visited,m))
    {
        path.push_back('L');
        solve(m,n,ans,newx,newy,visited,path);
        path.pop_back();
    }
    //up
    newx= x-1;
    newy=y;
    if(isSafe(newx,newy,n,visited,m))
    {
        path.push_back('L');
        solve(m,n,ans,newx,newy,visited,path);
        path.pop_back();
    }
      for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
            {
                visited[i][j]=0;
            }
        }
      
}

    
    
    
    
    
    
    public:
    vector<string> findPath(vector<vector<int>> &m, int n) {
        vector<string> ans;
        
        if(m[0][0]==0)
        return ans;
        
        int srcx=0;
        int srcy=0;
        
        vector<vector<int>> visited = m;
        
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
            {
                visited[i][j]=0;
            }
        }
        
    
        
        
        string path = "";
        solve(m,n,ans,srcx,srcy,visited,path);
        sort(ans.begin(),ans.end());
        return ans;
        
        
    }
};

    


//{ Driver Code Starts.

int main() {
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        vector<vector<int>> m(n, vector<int> (n,0));
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                cin >> m[i][j];
            }
        }
        Solution obj;
        vector<string> result = obj.findPath(m, n);
        sort(result.begin(), result.end());
        if (result.size() == 0)
            cout << -1;
        else
            for (int i = 0; i < result.size(); i++) cout << result[i] << " ";
        cout << endl;
    }
    return 0;
}
// } Driver Code Ends