問題描述：

Given a word, you need to judge whether the usage of capitals 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".

示例：

Input: "USA"
Output: True

Input: "FlaG"
Output: False

問題分析：

我們可以統計單詞中小寫字母的數目，最後根據小寫字母數目來進行判斷。

過程詳見程式碼：

class Solution {
public:
    bool detectCapitalUse(string word) {
        if(word.length() < 2) return true;
        int lower = 0;
        int len = word.length();
        for(int i = 0;i < len; i++)
        {
        	if(islower(word[i])) lower++;
		}
		
		if(islower(word[0])) return lower == len;
		else return lower == len - 1  || lower == 0 ;
    }
};