uZNx7k - Online C++ Compiler & Debugging Tool

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

int main() {
	freopen("SNUM.INP","r",stdin);
	freopen("SNUM.OUT","w",stdout);
	int n;
	cin >> n;
	vector<int>a(n);
	vector<int>b(100001,0);
	for (int i=0;i<n;i++) {
		cin >> a[i];
		b[a[i]]++;
	}
	for (int i=0;i<n;i++) {
		if (b[a[i]]==1) {
			cout << a[i] << " ";
		}
	}
}