LeetCode Detect Capital

原题链接在这里：https://leetcode.com/problems/detect-capital/#/description

题目：

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".

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

Example 1:

Input: "USA"
Output: True

Example 2:

Input: "FlaG"
Output: False

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

题解：

数大写的个数，对应三种cases: 1.count为0, 2. count 等于word.length(), 3. count 是1, 首字符大写.  

Time Complexity: O(word.length()). Space: O(1).

AC Java:

public class Solution {
    public boolean detectCapitalUse(String word) {
        int count = 0;
        for(int i = 0; i<word.length(); i++){
            if('Z'-word.charAt(i) >= 0){
                count++;
            }
        }
        return count == 0 || count == word.length() || (count==1 && 'Z'-word.charAt(0)>=0);
    }
}