k진수에서 소수 개수 구하기

Link

https://school.programmers.co.kr/learn/courses/30/lessons/92335

Deadline

Mar 7, 2023

Status

Archived

Type

string

문제

풀이

은찬


const solution = (n, k) => {
    let answer = 0;
    const transformed = [];
    
    const isPrime = (n) => {
        if(n <= 1){
            return false;
        }
        
        for(let i = 2; i <= Math.sqrt(n); i++){
            if(n % i === 0){
                return false;
            }
        }
        
        return true;
    }
    
    while(n){
        transformed.push(n % k);
        n = Math.floor(n / k);
    }
    
    transformed.reverse().join("").split("0").forEach((curr) => {
        if(curr && isPrime(curr)){
            answer++;
        }
    });
    
    return answer;
}

재영


const solution = (n, k) => n.toString(k).split('0').filter(isPrime).length;

const isPrime = (n) => {
  if (n < 2) return false;

  for (let i = 2; i <= Math.sqrt(n); i += 1) {
    if (n % i === 0) return false;
  }

  return true;
};

효성


function solution(n, k) {
    let answer = 0;
    const converted = n.toString(k);
    const splited = converted.split('0');
    
    splited.forEach(s => {
        if(isPrime(+s)) {
            answer += 1;
        }
    })

    return answer;
}

function isPrime(num) {
    if(num <= 1) {
        return false;
    }

    const squrt = Math.floor(Math.sqrt(num));
    for(let i = 2; i <= squrt; i++){
        if(num % i === 0){
            return false; 
        }
    }

    return true; 
}