code-graphs/dfs.cpp at main · Nickhil1737/code-graphs · GitHub

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

vector < vector <int> > adj;
int V,E,dfstime;
int discover[110];
int finished[110];
bool marked[110];
int parent[110];


void dfsvisit(int s)
{
    discover[s] = ++dfstime;
    marked[s] = 1;
    for(auto v:adj[s])
        if(!marked[v])
            dfsvisit(v);
    finished[s] = ++dfstime;
}
void dfs()
{
    for(int i = 1; i < V+1; ++i)
        parent[i] = -1,marked[i] = 0;
    dfstime = 0;

    for(int i = 1; i < V+1; ++i){
        if(!marked[i])
            dfsvisit(i);
    }

}


int main()
{
    cin>>V>>E;
    adj.resize(V+10);
    for(int i = 0; i < E; ++i){
        int x,y;    cin>>x>>y;
        adj[x].push_back(y);
    }
    dfs();

    for(int i = 0; i < V+1; ++i)
        cout<<discover[i]<<(i==V?'\n':' ');
    for(int i = 0; i < V+1; ++i)
        cout<<finished[i]<<(i==V?'\n':' ');

    return 0;
}