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[ํ”„๋กœ๊ทธ๋ž˜๋จธ์Šค LV.0] ํ•ฉ์„ฑ์ˆ˜ ์ฐพ๊ธฐ

by hyebin (Helia) 2022. 12. 29.
๋ฐ˜์‘ํ˜•

ํ•ฉ์„ฑ์ˆ˜ ์ฐพ๊ธฐ

๋ฌธ์ œ ์„ค๋ช…

์•ฝ์ˆ˜์˜ ๊ฐœ์ˆ˜๊ฐ€ ์„ธ ๊ฐœ ์ด์ƒ์ธ ์ˆ˜๋ฅผ ํ•ฉ์„ฑ์ˆ˜๋ผ๊ณ  ํ•ฉ๋‹ˆ๋‹ค. ์ž์—ฐ์ˆ˜ n์ด ๋งค๊ฐœ๋ณ€์ˆ˜๋กœ ์ฃผ์–ด์งˆ ๋•Œ n์ดํ•˜์˜ ํ•ฉ์„ฑ์ˆ˜์˜ ๊ฐœ์ˆ˜๋ฅผ return ํ•˜๋„๋ก solution ํ•จ์ˆ˜๋ฅผ ์™„์„ฑํ•ด ์ฃผ์„ธ์š”.

์ œํ•œ ์‚ฌํ•ญ

  • 1 ≤ n ≤ 100

์ž…์ถœ๋ ฅ ์˜ˆ

n result
10 5
15 8

์ž…์ถœ๋ ฅ ์˜ˆ ์„ค๋ช…

์ž…์ถœ๋ ฅ ์˜ˆ #1

  • 10 ์ดํ•˜ ํ•ฉ์„ฑ์ˆ˜๋Š” 4, 6, 8, 9, 10๋กœ 5๊ฐœ์ž…๋‹ˆ๋‹ค. ๋”ฐ๋ผ์„œ 5๋ฅผ return ํ•ฉ๋‹ˆ๋‹ค.

์ž…์ถœ๋ ฅ ์˜ˆ #2

  • 15 ์ดํ•˜ ํ•ฉ์„ฑ์ˆ˜๋Š” 4, 6, 8, 9, 10, 12, 14, 15๋กœ 8๊ฐœ์ž…๋‹ˆ๋‹ค. ๋”ฐ๋ผ์„œ 8์„ return ํ•ฉ๋‹ˆ๋‹ค.

์ œ์ถœ

import Foundation

func solution(_ n:Int) -> Int {
    if n < 4 {return 0}
    
    var answer = 0
    for i in 4...n{
        for j in 2..<i{
            if i%j == 0 {
                answer += 1
                break
            }
        }
    }
    
    return answer
}
n์ด 4๋ณด๋‹ค ์ž‘๋‹ค๋ฉด 0์„ ๋ฐ˜ํ™˜ (1์€ ์•ฝ์ˆ˜์˜ ๊ฐœ์ˆ˜๊ฐ€ 1๊ฐœ, 2,3์€ ์†Œ์ˆ˜์ด๊ธฐ ๋•Œ๋ฌธ์— ์•ฝ์ˆ˜์˜ ๊ฐœ์ˆ˜๊ฐ€ 2๊ฐœ)
4๋ถ€ํ„ฐ n๊นŒ์ง€ ๋‚˜๋ˆ„์–ด ๋–จ์–ด์ง€๋Š” ์ˆ˜๊ฐ€ ์žˆ๋‹ค๋ฉด answer๋ฅผ 1 ์ฆ๊ฐ€

๋‹ค๋ฅธ ํ’€์ด

import Foundation

func solution(_ n:Int) -> Int {
  return (1...n).filter { i in (1...i).filter { i % $0 == 0 }.count > 2 }.count
}
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