dfs && bfs

#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;

const int N = 100010, M = 100010;

struct Node
{
    int id;
    Node *next;
    Node(int _id): id(_id), next(NULL){}
}*head[N];  //邻接表 

bool st[N];
void add(int a, int b)
{
    auto temp = new Node(b);
    temp->next = head[a];
    head[a] = temp;
}

void dfs(int i)
{
    st[i] = true;
    printf("%d ", i);
    for(Node* p = head[i]; p; p = p->next)
    {
        int j = head[i]->id;
        if(!st[j]) dfs(j);
    }
}

void bfs(int i)
{
    queue<int> q;
    q.push(i);
    st[i] = true;
    while(!q.empty())
    {
        int j = q.front();
        q.pop();
        printf("%d ", j);
        for(auto p = head[j]; p; p = p->next)
        {
            j = p->id;
            if(!st[j])
            {
                st[j] = true;
                q.push(j);
            }
        }
    }
}


int main()
{
    int n, m;
    cin >> n >> m;
    while (m -- )
    {   
        int a,b;
        cin >> a >> b;
        add(a, b);
    }
    for (int i = 1; i <= n; i ++ )
    {
        if(!st[i])
        {
            bfs(i);
            dfs(i);
        }
    }
    return 0;

}