刚看到一个新容器，拿来试试就是不过

#include <iostream>
#include <unordered_set>
#include <algorithm> 
using namespace std;
int main() {
	int n, b;
	unordered_set <int> a;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> b;
		a.insert(b);
	}
	for (auto x : a) {
		cout << x << " ";
	}
}