The 67th Permutation Problem

    1#include <bits/stdc++.h>
    2using namespace std;
    3using ll = long long;
    4using i128 = __int128;
    5const int inf = 1e9;
    6const ll INF = 1e18; //❄️
    7void solve() {
    8    int n; cin >> n;
    9    n *= 3;
    10    vector<int> v;
    11    bool f = 1, s = 1;
    12    int cur = 1;
    13    int a = n;
    14    for (int i = 1; i <= n; i++) {
    15        if (f) {
    16            cout << cur << " ";
    17            f = 0;
    18            s = 1;
    19            cur++;
    20        } else {
    21            if (s) {
    22                cout << a-- << " ";
    23                s = 0;
    24            } else {
    25                cout << a-- << " ";
    26                f = 1;
    27            }
    28        }
    29    }
    30    cout << '\n';
    31}
    32int main() {
    33    ios::sync_with_stdio(0); cin.tie(0); 
    34    int t; cin >> t;
    35    while (t--) {
    36        solve();
    37    }
    38    return 0;
    39}