Strongly Connected components

// I can't tell you what it really is,
// I can only tell you what it feels like.
#include "bits/stdc++.h"
using namespace std;

#define int long long
#define F first
#define S second
#define rep(i,a,n) for (int i = a; i <= n; ++i)
#define fo(i, n)   for (int i = 1; i <= n; ++i)
#define all(v)  v.begin(), v.end()
#define pb push_back
#define P pair < int, int >
#define fast  ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
#define E cout << '\n'
const int N = 1e5 + 5;
int vis[N];

vector < int > g[N], revg[N], v;

void dfs(int node) {
	vis[node] = 1;
	for(auto i : g[node])
		if(!vis[i])
			dfs(i);
	v.push_back(node);
}
vector < int > let;
void revdfs(int node) {
	vis[node] = true;
	let.push_back(node);
	for(auto i : revg[node])
		if(!vis[i])
			revdfs(i);
}
inline void solve() {
	int k, n, m, ans(0), l, r;
	cin >> n;// number of nodes
	cin >> m;// number of edges
	for(int i = 1; i <= m; ++i) {
		cin >> l >> r;
		g[l].push_back(r);
		revg[r].push_back(l);
	}
	for(int i = 1; i <= n; ++i) {
		if(!vis[i])
			dfs(i);
	}
	memset(vis, 0, sizeof vis);
	cout << "Nodes with strongly connected components are \n";
	while(!v.empty()) {
		int i = v.back();
		if(!vis[i]) {
			revdfs(i);
			int ans = 0;
			for (auto i : let) {
			   cout << i << ' ';
			}
			let.clear();
		}
		v.pop_back();
		cout << '\n';
	}
}
signed main(){
   fast;
   solve();
   return 0;
}