C++ kosaraju's algorithm

kosaraju's algorithm
// 1. Topological sort of original graph G
// 2. Itearte over all the vertices on reverse graph RG, and perform dfs
	  on reverse graph 
// 3. Mark all the current visited node as one component

Note: its like onion-peeling algorithm and removal of sink nodes in 
Condensed connected graph
// =======================================================

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 1;

vector<int> gr[N], grr[N];
int vis[N];
int color[N];
vector<int> order;

void dfs1(int src) {
	vis[src] = 1;

	for (auto nbr : gr[src]) {
		if (!vis[nbr]) {
			dfs1(nbr);
		}
	}

	// i am at this point, bcz i have pushed all subtree
	order.push_back(src);
}

void dfs2(int src, int comp) {
	vis[src] = 1;
	color[src] = comp;
	for (auto nbr : grr[src]) {
		if (!vis[nbr]) {
			dfs2(nbr, comp);
		}
	}

}

int main() {

#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif

	int n, m;
	cin >> n >> m;

	for (int i = 0; i < m; i++) {
		int x, y;
		cin >> x >> y;
		gr[x].push_back(y);
		grr[y].push_back(x);
	}

	for (int i = 1; i <= n; i++) {
		if(!vis[i]){
			dfs1(i);
		}
		
	}

	reverse(order.begin(), order.end());
	memset(vis, 0, sizeof(vis));

	int comp = 1;

	for (auto x : order) {
		if (!vis[x]) {
			dfs2(x, comp++);
		}
	}

	cout << "Total SCC are " << comp - 1 << endl;

	for(int i=1;i<=n;i++){
		cout<<i<<"-->"<<color[i]<<endl;
	}

	return 0;
}
C++相关代码片段
