Foj 1649 Prime number or not

最新推荐文章于 2025-08-15 23:10:13 发布

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最新推荐文章于 2025-08-15 23:10:13 发布

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文章标签： java

本文介绍了一种使用Java实现的大数质数判断方法。通过利用BigInteger类及其isProbablePrime方法，可以高效地判断一个非常大的数是否为质数。这种方法适用于需要处理超长整数的情况。

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Accept: 238Submit: 1098
Time Limit: 2000 mSecMemory Limit : 32768 KB

Problem Description

Your task is simple. Give you a number N, you should judge whether N is a prime number or not.

Input

There are multiple test cases. For each test case, there is an integer N(2<=N<=10^18).

Output

For each test case, you should output whether N is a prime number or not. If N is a prime number , you should output "It is a prime number."; otherwise you should output "It is not a prime number.";

Sample Input

Sample Output

It is a prime number.

It is not a prime number.

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我发现java越来越暴力了

import java.math.BigInteger; import java.util.Scanner; public class Main { static BigInteger b; public static void main(String[] args) { Scanner in = new Scanner(System.in); while(in.hasNext()) { b=in.nextBigInteger(); if(b.isProbablePrime(1)) System.out.println("It is a prime number."); else System.out.println("It is not a prime number."); } } }