DFS.cpp

#include <bits/stdc++.h>

using namespace std;

#define ar array
#define ll long long

const int MAX_N = 1e5 + 5;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;

int n, m, vis[MAX_N];
vector<int> adj[MAX_N];

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

void solve() {
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) {
        if (vis[i]) continue;
        dfs(i);
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
    }
}