UVA 11561 / Flood Fill

/***
 created: 2022-06-20-02.38.10
***/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename U> using ordered_set=tree<U, null_type,less<U>,rb_tree_tag,tree_order_statistics_node_update>;
#define ll long long
#define test int tt; cin>>tt; for(int cs=1;cs<=tt;cs++)
#define get_lost_idiot return 0
#define nl '\n'

ll n,m,ans=0;
char a[105][105];
ll v[105][105];

bool valid(ll i,ll j)
{
    return (a[i][j]=='T');
}

void dfs(ll i,ll j)
{
   if(v[i][j] || a[i][j]=='#' || a[i][j]=='T') return;

   v[i][j]=1;

   if(a[i][j]=='G') ans++;

   if(valid(i,j+1)) return;
   if(valid(i,j-1)) return;
   if(valid(i+1,j)) return;
   if(valid(i-1,j)) return;

   dfs(i,j+1);
   dfs(i,j-1);
   dfs(i+1,j);
   dfs(i-1,j);
}


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    ll i,j,k,l;

    while(cin>>m>>n && n && m)
    {
        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                cin>>a[i][j];
                v[i][j]=0;
            }
        }

        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                if(a[i][j]=='P')
                {
                    dfs(i,j);
                    break;
                }
            }
        }

        cout<<ans<<nl;

        ans=0;
    }

    get_lost_idiot;
}

/*

7 4
#######
#P.GTG#
#..TGG#
#######
8 6
########
#...GTG#
#..PG.G#
#...G#G#
#..TG.G#
########

*/