usaco-practice/cses/Distinct Numbers.cpp

#include <algorithm>
#include <iostream>
#include <stdlib.h>
#include <vector>

using namespace std;

int main() {
  int n;
  cin >> n;
  vector<int> x;

  int a = 1;

  for (int i = 0; i < n; i++) {
    int j;
    cin >> j;
    x.push_back(j);
  }

  sort(x.begin(), x.end());

  for (unsigned int i = 0; i < x.size() - 1; i++) {
    // cout << x.at(i) << " ";
    if (x.at(i) < x.at(i + 1)) {
      a++;
    }
  }
  cout << a;
}