Untitled

 #include<bits/stdc++.h>
#define MAX  1000
#define pii  pair< int , int >
using namespace std;
 
int fx[] = { 1, -1, 0, 0 };
int fy[] = { 0, 0, 1, -1 };
char cell[100][100];
int dis[100][100];
int vis[100][100];
int row, col;
 
void BFS ( int sx, int sy )
{
    memset(vis, 0, sizeof(vis));
    vis[sx][sy] = 1 ;
    dis[sx][sy] = 0;
    queue<pair<int,int>>q;
    q.push({sx,sy});
 
    while( !q.empty() )
    {
        pair< int, int > top;
        top = q.front();
        q.pop();
 
        for( int k = 0 ; k<4 ; k ++ )
        {
            int tx = top.first+fx[k];
            int ty = top.second+fy[k];
 
            if( tx>=0 && tx<row && ty>=0 && ty<col && cell[tx][ty]== '.' && vis[tx][ty] == 0 )// "." means node ache!
            {
                vis[tx][ty] = 1;
                dis[tx][ty]= dis[top.first][top.second] + 1;
                q.push({ tx, ty });
            }
        }
    }
}

int main()
{
    FastIO;
    cin>>row>>col;
 
    for( int i = 0 ; i<row ; i++ )
    {
        for( int j = 0 ; j<col ; j++ )
        {
            cin >> cell[i][j];
        }
    }
}