백준 1978번

원본 : www.acmicpc.net/problem/1978

1978번: 소수 찾기

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Main {

	public static void main(String[] args) throws Exception {

		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));

		int n = Integer.parseInt(reader.readLine());
		int num[] = new int[n];
		
		String str = reader.readLine();
		for (int i = 0; i < num.length; i++) {
			num[i] = Integer.parseInt(str.split(" ")[i]);
		}
		
		int count = 0;
		for (int i = 0; i < num.length; i++) {
			int aliquotCount = 0;
			for (int j = 1; j <= num[i]; j++) {
				if (num[i] % j == 0) {
					aliquotCount++;
				}
			}
			if (aliquotCount == 2) {
				count++;
			}
		}
		
		writer.write(String.valueOf(count));

		writer.flush();
	}
	
}