USACO 2.1 Sort Three Valued Sequence

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

int main() {
  ifstream fin("sort3.in");
  ofstream fout("sort3.out");

  int count[4], a[4], t[1001], x, n, k = 0;
  memset(count, 0, sizeof(count));
  memset(a, 0, sizeof(a));

  fin >> n;
  while (fin >> x) {
    count[x]++;
    t[++k] = x;
  }

  for (int i = 1; i <= count[1] + count[2]; ++i){
    if (t[i] == 3)
      a[3]++;
    else if (t[i] == 2 && i <= count[1])
      a[1]++;
    else if (t[i] == 1 && i > count[1])
      a[2]++;
  }

  fout << a[3] + (a[1] > a[2] ? a[1] : a[2]) << endl;

  return 0;
}