[BOJ] 11724 : 연결 요소의 개수

#include <iostream>
#include <vector>
using namespace std;

int n, m, ans, vst[1001];
vector<int> gph[1001];

void dfs(int now) {
	vst[now] = 1;
	for (int nxt : gph[now]) if (!vst[nxt]) dfs(nxt);
}

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

	cin >> n >> m;
	for (int i = 0, u, v; i < m; i++) {
		cin >> u >> v;
		gph[u].push_back(v), gph[v].push_back(u);
	}

	for (int i = 1; i <= n; i++) if (!vst[i]) ans++, dfs(i);

	cout << ans;

	return 0;
}