Books exchange

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
//  freopen("output.txt", "w", stdout);
#endif

    int q;
    cin >> q;
    for (int i = 0; i < q; ++i) {
        int n;
        cin >> n;
        vector<int> p(n);
        for (int j = 0; j < n; ++j) {
            cin >> p[j];
            --p[j];
        }
        vector<int> used(n);
        vector<int> ans(n);
        for (int j = 0; j < n; ++j) {
            if (!used[j]) {
                vector<int> cur;
                while (!used[j]) {
                    cur.push_back(j);
                    used[j] = true;
                    j = p[j];
                }
                for (auto el : cur) ans[el] = cur.size();
            }
        }
        for (int j = 0; j < n; ++j) cout << ans[j] << " ";
        cout << endl;
    }

    return 0;
}