Submission #74275802

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

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

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    
    int n, m;
    cin >> n >> m;
    vector<string> g(n);
    for (int i=0; i<n; i++) cin >> g[i];
    
    vector<vector<bool>> vis(n, vector<bool>(m, false));
    auto dfs = [&](auto &self, int i, int j) -> bool {
      if (i < 0 || j < 0 || i >= n || j >= m) return true;
      if (g[i][j] == '#' || vis[i][j]) return false;
      vis[i][j] = true;
      bool ret = false;
      for (int k=0; k<4; k++) {
        int ni = i + di[k], nj = j + dj[k];
        ret |= self(self, ni, nj);
      }
      return ret;
    };
    
    int ans = 0;
    for (int i=0; i<n; i++) {
      for (int j=0; j<m; j++) {
        if (vis[i][j] || g[i][j] == '#') continue;
        ans += !dfs(dfs, i, j);
      }
    }
    
    cout << ans << '\n';
}

Submission Info

Judge Result