Natalia e os Animais

natalia.cpp

#include <bit/stdc++.h>

using namespace std;

const int maxn = 100010;

vector<int> v[maxn];
int vis[maxn];

void dfs(int x)
{ 
  vis[x] = 1;
  for (int u : v[x]) if (!vis[u]) dfs(u);
}

int main()
{
  int n, m;
  cin >> n >> m;
  
  for (int i = 0; i < m; i++) {
    
    int a, b;
    cin >> a >> b;
    
    v[a].push_back(b);
    v[b].push_back(a);
  }
  
  int ans = 0;
  for (int i = 1; i <= n; i++) if (!vis[i]) dfs(i), ans++;
  
  cout << ans << "\n";
}