๋ณธ๋ฌธ ๋ฐ”๋กœ๊ฐ€๊ธฐ
Algorithm

[Codeforces] 935A: Fafa and his Company(brute force)

by ์ฃผ๋ฐœ2 2020. 2. 21.
๋ฐ˜์‘ํ˜•

https://codeforces.com/problemset/problem/935/A

 

Problem - 935A - Codeforces

 

codeforces.com

๋ฌธ์ œ

ํŒŒํŒŒ๋Š” ๊ฑฐ๋Œ€ํ•œ ํ”„๋กœ์ ํŠธ์—์„œ ์ผํ•˜๋Š” ํšŒ์‚ฌ๋ฅผ ์†Œ์œ ํ•˜๊ณ  ์žˆ๋‹ค. ํŒŒํŒŒ์˜ ํšŒ์‚ฌ์—๋Š” n๋ช…์˜ ์ง์›์ด ์žˆ๋‹ค. ํšŒ์‚ฌ๊ฐ€ ์ƒˆ๋กœ์šด ํ”„๋กœ์ ํŠธ๋ฅผ ์‹œ์ž‘ํ•  ๋•Œ๋งˆ๋‹ค, ํŒŒํŒŒ๋Š” ์ด ํ”„๋กœ์ ํŠธ์˜ ์ž„๋ฌด๋ฅผ ๋ชจ๋“  ์ง์›๋“ค ์‚ฌ์ด์—์„œ ๋‚˜๋ˆ„์–ด์•ผ ํ•œ๋‹ค.

ํŒŒํŒŒ๋Š” ๋งค๋ฒˆ ์ด๋ ‡๊ฒŒ ํ•˜๋Š” ๊ฒƒ์ด ๊ทธ์—๊ฒŒ ๋งค์šฐ ํ”ผ๊ณคํ•˜๋‹ค๋Š” ๊ฒƒ์„ ์•Œ๊ฒŒ ๋œ๋‹ค. ๊ทธ๋ž˜์„œ ๊ทธ๋Š” ํŒ€์žฅ์œผ๋กœ์„œ ์ž์‹ ์˜ ํšŒ์‚ฌ์—์„œ ์ตœ๊ณ ์˜ l์‚ฌ์›์„ ๋ฝ‘๊ธฐ๋กœ ๊ฒฐ์‹ฌํ–ˆ๋‹ค. ํŒŒํŒŒ๋Š” ์ƒˆ๋กœ์šด ํ”„๋กœ์ ํŠธ๊ฐ€ ์žˆ์„ ๋•Œ๋งˆ๋‹ค ํŒ€์žฅ๋“ค ์‚ฌ์ด์—์„œ๋งŒ ์—…๋ฌด๋ฅผ ๋ถ„๋‹ดํ•˜๊ฒŒ ๋˜๋ฉฐ ๊ฐ ํŒ€์žฅ์€ ์ผ๋ถ€ ๊ธ์ •์ ์ธ ์ˆ˜์˜ ์ง์›์„ ๋‹ด๋‹นํ•˜๊ฒŒ ๋œ๋‹ค. ์ด ๊ณผ์ •์„ ํŒ€์žฅ๋“ค์—๊ฒŒ ๊ณตํ‰ํ•˜๊ฒŒ ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ๊ฐ์ž๊ฐ€ ๋™์ผํ•œ ์ˆ˜์˜ ์ง์›์„ ์ฑ…์ž„์ ธ์•ผ ํ•œ๋‹ค. ๋”๊ตฌ๋‚˜ ํŒ€์žฅ์ด ์•„๋‹Œ ๋ชจ๋“  ์ง์›์€ ์ •ํ™•ํžˆ ํ•œ ํŒ€์žฅ์˜ ์ฑ…์ž„ ํ•˜์— ์žˆ์–ด์•ผ ํ•˜๊ณ , ๋‹ค๋ฅธ ํŒ€์žฅ์„ ์ฑ…์ž„์ง€๋Š” ํŒ€์žฅ์€ ์—†๋‹ค.

์ง์› ์ˆ˜ n๋ช…์„ ๊ณ ๋ คํ•  ๋•Œ, ํŒŒํŒŒ๊ฐ€ ์–ผ๋งˆ๋‚˜ ๋งŽ์€ ๋ฐฉ๋ฒ•์œผ๋กœ ํŒ€์žฅ ์ˆ˜๋ฅผ ์„ ํƒํ•  ์ˆ˜ ์žˆ๋Š”์ง€ ์•Œ์•„๋ณด์„ธ์š” l์‚ฌ์›์„ ๊ท ๋“ฑํ•˜๊ฒŒ ๋‚˜๋ˆŒ ์ˆ˜ ์žˆ๋„๋ก.

Note

๋‘ ๋ฒˆ์งธ ์ƒ˜ํ”Œ์—์„œ Fafa๋Š” ์„ธ ๊ฐ€์ง€ ๋ฐฉ๋ฒ•์„ ๊ฐ€์ง€๊ณ  ์žˆ๋‹ค.

9๋ช…์˜ ์ง์›์„ ์ฑ…์ž„์ง€๊ณ  ํŒ€์žฅ์œผ๋กœ 1๋ช…๋งŒ ๋ฝ‘๋Š”๋‹ค.
๊ฐ์ž๊ฐ€ ์ฑ…์ž„์ง€๊ณ  4๋ช…์˜ ์ง์›์„ ๋‘๊ณ  2๋ช…์˜ ์ง์›์„ ํŒ€์žฅ์œผ๋กœ ์„ ์ •ํ•œ๋‹ค.
๊ฐ์ž๊ฐ€ ์ฑ…์ž„์ง€๊ณ  1์ธ 1์กฐ๋กœ 5๋ช…์˜ ์ง์›์„ ํŒ€์žฅ์œผ๋กœ ์„ ์ •ํ•œ๋‹ค.


์ฝ”๋“œ

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(bf.readLine());
		int count = 0;
		for(int i=1; i<=n/2; i++) {
			if((n-i) % i == 0) {
				count ++;
			}
		}
		System.out.println(count);
		bf.close();
	}

}

ํ’€์ด

์ž…๋ ฅ๋ฐ›์€ n๊นŒ์ง€๊ฐ€ ์•„๋‹Œ n/2๊นŒ์ง€๋งŒ ๋ฐ˜๋ณต๋ฌธ์„ ๋Œ๋ ค๋„ ์ƒ๊ด€์ด ์—†๋‹ค.

n์ด 10์ผ๋•Œ n/2 = 5 ์ด๊ณ , 6 ~ 9๊นŒ์ง€๋Š” ํŒ€์žฅ์„ ๋ฝ‘์•„๋„ ๋ฐฉ๋ฒ•์ด ์—†๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค.

๋”ฐ๋ผ์„œ ํ•˜๋‚˜ํ•˜๋‚˜ ์™„์ „ํƒ์ƒ‰์œผ๋กœ ๋ฝ‘์„ ์ˆ˜ ์žˆ๋Š” ๊ฒฝ์šฐ์˜์ˆ˜๋ฅผ ์ฐพ์•„์ค€๋‹ค.

์ง์›์ด n ๋ช…์ผ๋•Œ, ํŒ€์žฅ์„ 1๋ถ€ํ„ฐ n/2๊นŒ์ง€ ๋ฝ‘์œผ๋ฉด์„œ ๋‚˜๋ˆ„์–ด ๋–จ์–ด์งˆ๋•Œ -> ํŒ€์žฅ์„ ๋ฝ‘์„ ์ˆ˜ ์žˆ์œผ๋ฏ€๋กœ ++ํ•ด์ค€๋‹ค.

 

10๋ช… -> ํŒ€์žฅ์€ 1๋ช…, 2๋ช…, 5๋ช… ๋ฝ‘์„ ์ˆ˜ ์žˆ๋‹ค.

(10-1) % 1 == 0

(10-1) % 2 == 0

(10-1) % 5 == 0

 

 

๋ฐ˜์‘ํ˜•

๋Œ“๊ธ€