Submission #52870949

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Source Code Expand

#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/multiprecision/cpp_int.hpp>

using namespace std;
using namespace atcoder;
namespace mp = boost::multiprecision;

using ll = long long;
using pll = pair<ll,ll>;
using bint = mp::cpp_int;
using mint = modint998244353;

ll H, W;
vector<string> S;
vector<vector<bool>> used;
vector<vector<bool>> used_this_time;

ll dj[] = {0, 1, 0, -1};
ll di[] = {1, 0, -1, 0};

ll dfs(ll i, ll j)
{
  if(S[i][j]=='#')
  {
    return 0LL;
  }
  if(used_this_time[i][j]==true)
  {
    return 0LL;
  }
  used[i][j]=true;
  used_this_time[i][j]=true;
  ll ret = 1LL;

  for(ll a = 0;a < 4;a++)
  {
    ll ni = i + di[a];
    ll nj = j + dj[a];
    if(0 <= ni && ni < H && 0 <= nj && nj < W)
    {
      if(S[ni][nj]=='#')
      {
        return ret;
      }
    }
  }

  for(ll a = 0;a < 4;a++)
  {
    ll ni = i + di[a];
    ll nj = j + dj[a];
    if(0 <= ni && ni < H && 0 <= nj && nj < W)
    {
      ret += dfs(ni, nj);
    }
  }
  return ret;
}

int main()
{
  cin >> H >> W;
  S.resize(H);
  used.resize(H, vector<bool>(W, false));
  for(auto& s:S)
  {
    cin >> s;
  }
  ll ans = 0LL;
  for(ll i = 0;i < H;i++)
  {
    for(ll j = 0;j < W;j++)
    {
      if(used[i][j]==false)
      {
        used_this_time = vector<vector<bool>>(H, vector<bool>(W, false));
        ll ret = dfs(i, j);
        ans = max(ans, ret);
      }
    }
  }
  cout << ans << endl;
  return 0;
}

Submission Info

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