연결 요소의 개수

#include <iostream> #include <vector> std::vector<int> v[1001]; bool visited[1001]; int N, M, ans; void io_faster() { std::ios_base::sync_with_stdio(false); std::cin.tie(0); std::cout.tie(0); } void input() { int a, b; io_faster(); std::cin >> N >> M; for(int i = 0 ; i < M ; i++) { std::cin >> a >> b; v[a].push_back(b); v[b].push_back(a); } } void dfs(int index) { int size = v[index].size(); for (int i = 0 ; i < size ; i++) { if (visited[v[index][i]]) continue; visited[v[index][i]] = 1; dfs(v[index][i]); } } void solve() { for (int i = 1 ; i <= N ; i++) { if (visited[i]) continue; visited[i] = 1; dfs(i); ans++; } std::cout << ans; } int main() { input(); solve(); return (0); }