Here's my wrong solution, can sb view the code and help me?
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

vector<int> pos;
vector<vector<int>> in;
vector<vector<int>> out;
vector<int> ans;

void lets_go(int i)
{
    for (int j = 0; j < in[i].size(); j++)
    {
        if (pos[in[i][j]] == 0)
        {
            lets_go(in[i][j]);
        }
    }
    pos[i] = 1;
    ans.push_back(i);
    for (int j = 0; j < out[i].size(); j++)
    {
        if (pos[out[i][j]] == 0)
        {
            lets_go(out[i][j]);
        }
    }
}

int main()
{
    int n;
    cin >> n;
    in.resize(n);
    out.resize(n);
    pos.resize(n, 0);
    for (int i = 0; i < n; i++)
    {
        int a;
        cin >> a;
        while (a != 0)
        {
            if (a != 0)
            {
                in[a - 1].push_back(i);
                out[i].push_back(a - 1);
                cin >> a;
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (pos[i] == 0)
        {
            lets_go(i);
        }
    }
    for (int i = 0; i < n; i++)
    {
        cout << ans[i] + 1 << " ";
    }
}