competitive-programming/graph.cpp at master · mangesh-trimbake/competitive-programming · GitHub

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#include <bits/stdc++.h>

using namespace std;

int mx = INT_MAX;

const int arr_limit = 1e7+10;

//int arr[arr_limit];

const int graph_v_limit = 1e5+10;


vector<int> g[graph_v_limit];

bool visited[graph_v_limit];

void dfs(int vertex){

	cout << vertex<< endl;
	visited[vertex] = 1;
	for(auto child : g[vertex]){

		if(visited[child]) continue;

		dfs(child);
	}

}

bool has_cycle(int vertex){

	cout << vertex<< endl;
	visited[vertex] = 1;
	for(auto child : g[vertex]){

		if(visited[child]){
			cout<<" making cycle";
			return true;
		}

		has_cycle(child);
	}

	cout << " oustside for";
	return false;

}


int main(){

	// int l = sizeof(g)/sizeof(g[0]);

	// cout<< "hello world " << l << typeid(g[0]).name() << endl;

	// cout<< mx;

	int v,e;
	cin >> v >> e;

	for(int i=0; i<e;++i){
		int v1,v2;
		cin >> v1 >>v2;
		g[v1].push_back(v2);
		g[v2].push_back(v1);
	}

	cout << has_cycle(0) << endl;


	return 1;
}