프로그래머스 소수찾기
import java.util.HashSet; class Solution { public int solution(String numbers) { HashSet set = new HashSet(); permutation("", numbers, set); int count = 0; while(set.iterator().hasNext()){ int a = set.iterator().next(); set.remove(a); if(a==2) count++; if(a%2!=0 && isPrime(a)){ count++; } } return count; } public boolean isPrime(int n){ if(n==0 || n==1) return false; for(int i=3; i