2667.cpp

// Authored by : 0silver00
// Co-authored by : -
// http://boj.kr/118e3a5900f94c4aae7aff09c263ef06
#include <bits/stdc++.h>
using namespace std;

#define X first
#define Y second
int dx[4] = { 1, 0, -1, 0 };
int dy[4] = { 0, 1, 0, -1 };
int n;
string board[27];
int vis[27][27];

int main(void){
  ios::sync_with_stdio(0);
  cin.tie(0);

  cin >> n;
  for(int i = 0; i < n; i++) {
    cin >> board[i];
  }

  int count = 0;
  vector <int> ans;

  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (board[i][j] == '0' || vis[i][j] == 1)
        continue;
      queue < pair<int, int> > Q;
      vis[i][j] = 1;
      Q.push({ i, j });
      int width = 1;
      count++;
      while (!Q.empty()) {
        auto cur = Q.front();
        Q.pop();
        for (int dir = 0; dir < 4; dir++) {
          int nx = cur.X + dx[dir];
          int ny = cur.Y + dy[dir];
          if (nx < 0 || nx >= n || ny < 0 || ny >= n)
            continue;
          if (board[nx][ny] == '0' || vis[nx][ny] == 1)
            continue;
          Q.push({ nx, ny });
          vis[nx][ny] = 1;
          width++;
        }
      }
      ans.push_back(width);
    }
  }

  cout << count << '\n';
  sort(ans.begin(), ans.end());

  for (int i : ans)
    cout << i << '\n';

  return 0; 
}