백준 11653번

원본 : www.acmicpc.net/problem/11653

11653번: 소인수분해

 

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());
        
        if(n != 1) {
            if (isPrimeNum(n)) {
            writer.write(n + "\n");
            } else {
                int mod = 2;
                while(true) {
                    if (n % mod == 0) {
                        while(true) {
                            writer.write(mod + "\n");
                            n /= mod;
                            if (n % mod != 0) {
                                break;
                            }
                        }
                    }
                    mod++;
                    if (n == 1) {
                        break;
                    }
                }
            }
        }
        
		writer.flush();
	}
    
    public static boolean isPrimeNum(int num) {
        int count = 0;
        for (int i = 1; i <= num; i++) {
            if (num % i == 0) {
                count++;
            }
            if (count > 2) {
                return false;
            }
        }
        
        return true;
    }
	
}