题解 | 不重复数字

#include <iostream>
#include <unordered_set>
#include <vector>
using namespace std;

int main() {
    int t, n, num;
    cin >> t;
    // cout << t << endl;

    while (t--) {
        cin >> n;
        // cout << n << endl;
        unordered_set<int> exist;
        vector<int> b;

        for (int i = 0; i < n; ++i) {
            cin >> num;
            if (!exist.count(num)) {
                exist.insert(num);
                b.push_back(num);
            }
        }

        for (const auto& num : b) {
            cout << num << " ";
        }
        cout << endl;
    }

    return 0;
}