Contest1334/B.cpp

#include <bits/stdc++.h>
using namespace std;
 
const int MXAN = 200 + 10;
int Next[4][2] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
int a[MXAN][MXAN];
int sum[MXAN][MXAN];
int n, m;
 
int Bfs(int x, int y)
{
    int res = 0;
    queue<pair<int, int> > que;
    que.push(make_pair(x, y));
    a[x][y] = 0;
    while (!que.empty())
    {
        res++;
        int x = que.front().first;
        int y = que.front().second;
        que.pop();
        for (int i = 0;i < 4;i++)
        {
            int tx = x + Next[i][0];
            int ty = y + Next[i][1];
            if (a[tx][ty] == 1)
            {
                a[tx][ty] = 0;
                que.push(make_pair(tx, ty));
            }
        }
    }
    return res;
}
 
int main()
{
    int t;
    cin >> t;
    while (t--)
    {
 
        cin >> n >> m;
        for (int i = 1;i <= n;i++)
            for (int j = 1;j <= m;j++)
                cin >> a[i][j];
        int res = 0;
        for (int i = 1;i <= n;i++)
            for (int j = 1;j <= m;j++)
            {
                if (a[i][j] == 1)
                {
                    res = max(res, Bfs(i, j));
                     
                }
            }
        cout << res << endl;
    }
 
    return 0;
}