팩토리얼 숫자 빈도수 더블릿

#include <stdio.h>
#define ten 10
 
int arr[1000000] = { 0 };
int cnt = 1;
int num[20] = { 0 };
 
int main() {
    int n,up=0;
    scanf("%d", &n);
 
    arr[1] = 1;
    if (n == 1)
        num[1] = 1;
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= cnt; j++) {
            arr[j] = (arr[j] * i + up);
            up = (arr[j] / ten);
            arr[j] %= ten;        
            if (i == n) {                
                num[arr[j] % ten] += 1;
            }            
        }
        while (up != 0) {
            arr[++cnt] = up % ten;
            if (i == n) {                
                num[ up % ten ] += 1;
            }            
            up /= ten;            
        }
    }
 
    printf("%d! --\n", n);
    for (int i = 0; i < 10; i++) {
        printf("   (%d)  %3d ",i,num[i]);
        if (i == 4)
            printf("\n");
    }
}