Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number.
For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13, 17, 19″.
The Sieve of Eratosthenes is one of the most efficient ways to find all primes smaller than n when n is smaller than 10 million or so.
Following is the algorithm to find all the prime numbers less than or equal to a given integer n by Eratosthenes’ method:
- Create a list of consecutive integers from 2 to n: (2, 3, 4, …, n).
- Initially, let p equal 2, the first prime number.
- Starting from p, count up in increments of p and mark each of these numbers greater than p itself in the list. These numbers will be 2p, 3p, 4p, etc.; note that some of them may have already been marked.
- Find the first number greater than p in the list that is not marked. If there was no such number, stop. Otherwise, let p now equal this number (which is the next prime), and repeat from step 3.
When the algorithm terminates, all the numbers in the list that are not marked are prime.
public List<Integer> findPrimeNumbers(int n) { boolean[] isPrime = new boolean[n+1]; Arrays.fill(isPrime, 2, n+1, true); for(int i=2; i*i <= n; i++) { if(isPrime[i]) { for(int j = i; i*j <= n; j++) { isPrime[i*j] = false; } } } // output all prime numbers List<Integer> result = new ArrayList<>(); for(int i=0; i<=n; i++) { if(isPrime[i]) { result.add(i); } } return result; }
相关推荐
此外,标签"find_prime_numbers"提示我们这是一个关于寻找素数的特定任务,可能还包括了如何存储和处理这些数据。在实际项目中,我们可能会考虑将素数存储在一个数组或链表中,然后进行进一步的分析或操作。 总结,...
在本篇文章中,我们将详细探讨`List<T>`的`FindAll`方法,并通过四种不同的写法来演示如何使用这个功能来筛选满足特定条件的元素。`FindAll`方法用于在列表中找到符合指定条件的所有元素,返回一个新的`List<T>`实例...
c语言入门 c语言_leetcode题解448-find-all-numbers-disappeared-in-an-array.c
Using this program you can find out the prime numbers between 1 to 100, 100 to 999 etc. You just need to input the range, for e.g. if you want the prime numbers 100 to 999 then enter numbers 100 and ...
具体错误信息sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target指出Java虚拟机(JVM)无法找到一个可信的路径来验证服务器提供的SSL/TLS...
正确地配置和管理信任链可以确保系统的安全性,同时避免出现“unable to find valid certification path to requested target”的错误。在实际操作中,应始终优先考虑增强安全性,而非简单地绕过证书验证。对于...
prime_numbers = find_prime_numbers(limit) print(prime_numbers) ``` 这段代码运行后,会输出1到100之间的所有素数。 如果你没有Python运行环境,可以使用在线Python编辑器,如链接中提供的Runoob在线Python编辑...
`find-up`是一个非常实用的工具,它允许开发者从当前目录开始,向上遍历父目录,直到找到指定的文件或者达到根目录为止。这个工具由Sindre Sorhus创建,他在开源社区中贡献了大量的实用模块,极大地便利了Node.js的...
Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four ...
findDisappearedNumbers.py
在Mac操作系统中,"Find Any File"是一款非常实用的图形化文件搜索工具,它为用户提供了方便快捷的方式来查找计算机中的文件。与系统内置的Spotlight相比,Find Any File更注重于搜索性能,允许用户根据更多自定义...
《Any to Icon v3.50:批量图片转图标的专业工具》 在信息化时代,图标作为用户界面的重要组成部分,其设计与制作对于软件的用户体验至关重要。而【Any to Icon v3.50】正是这样一款专业且实用的工具,它能够帮助...
findall()函数是re模块中一个非常常用的函数,它可以找出字符串中所有与正则表达式模式相匹配的所有子串,并以列表的形式返回。本文主要解析了findall()函数返回值的不同展现方式。 首先,要理解findall()函数...
### 启动Oracle Developer时报Unable to find a Java Virtual Machine #### 环境 - 操作系统:Windows 7 x64 - 数据库版本:Oracle 11g R2 - JDK版本:JDK 6 x64 #### 问题描述 在首次启动Oracle SQL Developer时...
`find` 和 `findAll` 是Yii中的两个重要方法,用于获取数据模型的单个对象或对象集合。当我们只需要特定字段,而不是整个对象的所有字段时,可以使用 `CDbCriteria` 对象或参数化的查询方式来实现。 首先,让我们来...
- See all assets not being referenced by any other asset so you can delete them all without worrying about breaking any references. - GUID Tools Advanced tool where you can see GUID of each asset ...
本项目“Find_The_Prime.rar_The Prime_prime number vhdl”显然是一个使用VHDL编写的电路设计,其目标是实现一个素数搜寻器。下面我们将深入探讨VHDL编程、素数的概念以及如何在硬件中实现素数检测。 1. VHDL基础...
This presupposes a knowledge about how to find the prime factors of 8. But since 8x only has prime factors that are primes less than or equal to 8, we need only consider relatively small primes even ...
本篇文章将详细讲解`List<T>`的一些关键方法,包括`Find`、`Exists`、`FindAll`以及`Sort`,并结合实际范例进行深入解析。 `List<T>`是泛型类,它继承自`Collection<T>`,实现了`IList<T>`接口,用于存储固定数量的...