https://www.acmicpc.net/problem/2839

๐Ÿ“ ํ’€์ด : 5kg ๋ด‰์ง€ ์ตœ๋Œ€ ์‚ฌ์šฉ ํ›„, ๋‚จ์€ ๋ฌด๊ฒŒ์— ๋”ฐ๋ผ ์กฐ์ •

import java.io.*;
public class Main {
// ์„คํƒ• Nkg ๋ฐฐ๋‹ฌ ์‹œ ๋ด‰์ง€(3/5kg)์˜ ์ตœ์†Œ ๊ฐœ์ˆ˜ ์ถœ๋ ฅ(๋ถˆ๊ฐ€๋Šฅ ์‹œ -1)
public static void main(String[] args) throws IOException {
/* [1] ์ž…๋ ฅ */
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int N = Integer.parseInt(br.readLine()); // ์„คํƒ• Nkg (3 โ‰ค N โ‰ค 5000)
/* [2] ๊ณ„์‚ฐ */
int cnt = 0; // ๋ด‰์ง€ ๊ฐœ์ˆ˜
cnt += N / 5; // 5kg ๋ด‰์ง€ ์ตœ๋Œ€ํ•œ ๋งŽ์ด ์‚ฌ์šฉ
N %= 5;
while (cnt > 0 && N % 3 != 0) { // ๋‚จ์€ ์„คํƒ•์ด 3kg ๋ด‰์ง€๋กœ ๋‚˜๋ˆ„์–ด๋–จ์–ด์งˆ ๋•Œ๊นŒ์ง€ ๋ฐ˜๋ณตโœจ
cnt--;
N += 5;
}
cnt += N / 3; // 3kg ๋ด‰์ง€ ์‚ฌ์šฉ
N %= 3;
/* [3] ์ถœ๋ ฅ */
System.out.println(N == 0 ? cnt : -1); // ๋‚˜๋ˆ„์–ด๋–จ์–ด์ง€๋ฉด ๋ด‰์ง€์˜ ์ด ๊ฐœ์ˆ˜ ์ถœ๋ ฅ
}
}
yewon31