本文是在学习中的总结,欢迎转载但请注明出处:http://blog.csdn.net/pistolove/article/details/41486885 通过本文你可能学到的知识如下: (1)理解本题的解题思路,在以后类似的场景中,如果没有想到比较好的方法,可以考虑使用本文的方法,虽然效率不是特别高. (2)能够对字符串的截取和HashMap相关操作有所学习. Roman to Integer Given a roman numeral, convert it to an integer. I…

Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 Have you thought about this? Here are some good questions to ask before coding. Bonus points for you if you have already thought through this! If the integer'…

Integer.parseInt 处理一个空字符串, 结果出错了, 程序没有注意到,搞了很久, 引发了血案啊!! 最后,终于 观察到了, 最后的部分: Caused by: java.lang.NoClassDefFoundError: Could not initialize class com.lk.common.util.LKUtil 还以为是class 不存在呢!! 于是,反复的复制啊, 黏贴啊, 我擦, 明明LKUtil就在那里的啊!!! 怎么回事! 实际原因就是这个啊: Caused…

最近看到一个多线程面试题,有三个线程分别打印A.B.C,请用多线程编程实现,在屏幕上循环打印10次ABCABC- 看到这个题目,首先想到的是解决方法是定义一个Integer类对象,初始化为0,由3个线程共享,如果Integer对象取余3之后等于0,则打印A,同时进行加1操作:如果Integer对象取3之后等于1,则打印B,同时进行加1操作:如果Integer对象取3之后等于1,则打印C,如果循环打印了10次的话,就退出线程. /** * ThreeThread * 3个线程测试 */ publi…

Given a positive integer n and you can do operations as follow: If n is even, replace n with n/2. If n is odd, you can replace n with either n + 1 or n - 1. What is the minimum number of replacements needed for n to become 1? Example 1: Input: 8 Outp…

Given a positive integer n, break it into the sum of at least two positive integers and maximize the product of those integers. Return the maximum product you can get. For example, given n = 2, return 1 (2 = 1 + 1); given n = 10, return 36 (10 = 3 +…

Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1. For example, 123 -> "One Hundred Twenty Three" 12345 -> "Twelve Thousand Three Hundred Forty Five" 1234567 -&g…

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 罗马数转化成数字问题,我们需要对于罗马数字很熟悉才能完成转换.以下截自百度百科: 罗马数字是最早的数字表示方式,比阿拉伯数字早2000多年,起源于罗马. 如今我们最常见的罗马数字就是钟表的表盘符号:Ⅰ,Ⅱ,Ⅲ,Ⅳ(IIII),Ⅴ,Ⅵ,Ⅶ,Ⅷ,Ⅸ,Ⅹ,Ⅺ,Ⅻ…… 对应阿拉伯数字(就是现…

Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 之前那篇文章写的是罗马数字转化成整数(http://www.cnblogs.com/grandyang/p/4120857.html), 这次变成了整数转化成罗马数字,基本算法还是一样.由于题目中限定了输入数字的范围(1 - 3999), 使得题目变得简单了不少. 基本字符 I V…

Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases. Notes: It is intended for this problem to be spe…