BOJ 26099 - 설탕 배달 2 [C]

문제

링크

풀이

#include <stdio.h>
 
int main(void) {
  long long n, three = 0, five = 0;
 
  scanf("%lld", &n);
  five = n / 5;
  n %= 5;
 
  switch (n) {
    case 1: five--; n += 5; three = n / 3; break;
    case 2: five -= 2; n += 10; three = n / 3; break;
    case 3: three = n / 3; break;
    case 4: five--; n += 5; three = n / 3; break;
  }
  
  if (five < 0) printf("-1");
  else printf("%lld", three + five);
  return 0;
}