P1459 三值的排序 Sorting a Three-Valued

#include <cstdio>
#include <iostream>
using namespace std;
int num[1001], count[4], a[4], n, k = 1;
int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++, k++) {
        scanf("%d", &num[k]);
        count[num[k]]++; 
    }
    for (int i = 1; i <= count[1] + count[2]; i++) {
        if (num[i] == 3) {
            a[3]++;
        }
        else if (num[i] == 2 && i <= count[1]) {
            a[1]++;
        }
        else if (num[i] == 1 && i > count[1]) {
            a[2]++;
        }
    }
    printf("%d\n", a[3] + (a[1] > a[2] ? a[1] : a[2]));
    return 0;
}