Fill

#include <iostream>
#include <fstream>
#include <stack>

using namespace std;
stack <pair <int, int> > t;

int a[1000][1000];

int Fill(int i, int j)
{
    t.push(make_pair(i, j));
    int cnt = 0;
    while(!t.empty())
    {
        i = t.top().first;
        j = t.top().second;
        t.pop();
        a[i][j] = 0;
        cnt++;
        if(a[i + 1][j] == 1)
            t.push(make_pair(i + 1, j));
        if(a[i - 1][j] == 1)
            t.push(make_pair(i - 1, j));
        if(a[i][j + 1] == 1)
            t.push(make_pair(i, j + 1));
        if(a[i][j - 1] == 1)
            t.push(make_pair(i, j - 1));
    }
    return cnt;
}

int main()
{
    int i, j, l, c, nrob, obmax, x;
    ifstream fin("date.in");
    fin >> l >> c;
    for(i = 1; i <= l; i++)
        for(j = 1; j <= c; j++)
            fin >> a[i][j];
    fin.close();
    nrob = obmax = 0;
    for(i = 1; i <= l; i++)
    {
        for(j = 1; j <= c; j++)
        {
            if(a[i][j] == 1)
            {
                nrob++;
                x = Fill(i, j);
                obmax = max(obmax, x);
            }
        }
    }
    cout << nrob;
    return 0;
}