Leetcode之Detect Capital 问题

问题描述：

Given a word, you need to judge whether the usage of capitals(大写字母) in it is right or not.

We define the usage of capitals in a word to be right when one of the following cases holds:

1. All letters in this word are capitals, like "USA".
2. All letters in this word are not capitals, like "leetcode".
3. Only the first letter in this word is capital if it has more than one letter, like "Google".

Otherwise, we define that this word doesn't use capitals in a right way.

Note: The input will be a non-empty word consisting of uppercase and lowercase latin letters.

示例：

Input: "USA"   Output: True

Input: "FlaG"  Output: False

问题来源：Detect Capital(详细地址：https://leetcode.com/problems/detect-capital/description/)

思路分析：在这我们就不调用库函数了，直接和'Z'比较就行了。我们在这将字符串先转化成数组好了，要是觉得浪费空间的话，其实也是可以不用的，直接调用charAt()方法进行比较，接着记录下每个字符串中出现大写字母的次数。情况一：所有的字符都是大写；情景二：没有一个是大写的；情景三：只有第一个是大写的，其他的都是小写的。以上三种情况下，返回的都是true，其他都是false。

代码：