1344A - Hilbert's Hotel - CodeForces Solution

#include <bits/stdc++.h>
#define int long long
using namespace std;

const int MOD = 1000000007;

signed main()
{
#ifdef ONLINE_JUDGE
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#endif
#ifndef ONLINE_JUDGE
#endif

    int T;
    cin >> T;
    while (T--)
    {
        int n;
        cin >> n;
        // cout << n << endl;
        vector<int> a(n);
        for (int i = 0; i < n; i++)
            cin >> a[i];
        vector<bool> vis(n, false);
        for (int i = 0; i < n; i++)
        {
            // cout << ((a[i] + i) % n + n) % n << " ";
            vis[((a[i] + i) % n + n) % n] = true;
        }
        // cout << "hello" << endl;
        // cout << endl;
        bool flag = true;
        for (int i = 0; i < n; i++)
        {
            if (!vis[i])
                flag = false;
        }
        if (flag)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
}