Generator - BinCoin

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
struct node
{
    int val = -1;
    int child[2] = {-1, -1};
};
vector<node> tri;
int dfs_rand(int node)
{
    if(tri[node].child[0]==-1)
    {
        cout<<tri[node].val<<" ";
        return 0;
    }
        uniform_int_distribution<int> rnd(0,1);
    int goi = rnd(gen);
    dfs_rand(tri[node].child[goi]);
    cout<<tri[node].val<<" ";
    dfs_rand(tri[node].child[goi^1]);
    return 0;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, k;
    cin>>n>>k;
    int shuff[n+1];
    for(int i=0; i<=n; i++)
    {
        shuff[i] = i;
    }
    for(int i=1; i<=n; i++)
    {
        uniform_int_distribution<int> rnd(1,n);
        swap(shuff[i], shuff[rnd(gen)]);
    }
    tri.clear(); tri.push_back(node());
    tri[0].val = shuff[1];
    vector<int> childless; childless.push_back(0);
    while((int)tri.size()<n)
    {
        uniform_int_distribution<int> rnd(0,(int)childless.size()-1);
        for(int i=0; i<(int)childless.size(); i++)
        {
            swap(childless[i], childless[rnd(gen)]);
        }
        int expan = childless.back();
        node add_1, add_2;

        tri[expan].child[0] = tri.size(); tri[expan].child[1] = tri.size()+1;

        childless.pop_back();

        childless.push_back(tri.size()); childless.push_back(tri.size()+1);

        add_1.val = shuff[tri.size()+1]; tri.push_back(add_1);
        add_2.val = shuff[tri.size()+1]; tri.push_back(add_2);
    }
    cout<<n<<" "<<k<<endl;
    for(int i=0; i<k; i++)
    {
        dfs_rand(0);
        cout<<endl;
    }
    return 0;
}