CTCI Challange, DAY 16

Day 16:-

Problem Statement:-Time Complexity: Primality

Simple problem,If its even no then its definately not prime,if its odd no,then loop n/2 times and try to find the divisor if not found any then its prime.


Solution:-

import java.util.Scanner;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int p = in.nextInt();
        for (int a0 = 0; a0 < p; a0++) {
            int n = in.nextInt();

            System.out.println(isPrime(n));
        }
    }

    private static String isPrime(int n) {
        if (n==1){
            return "Not prime";
        }
        if (n==2) return "Prime";
        if (n % 2 == 0) {
            return "Not prime";
        }
        for (int i = 3; i <= Math.sqrt(n); i++) {
            if (n % i == 0) {
                return "Not prime";
            }
        }
        return "Prime";
    }
}