520. Detect Capital

1. Question

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

• All letters in this word are capitals, like "USA".
• All letters in this word are not capitals, like "leetcode".
• Only the first letter in this word is capital, like "Google".

Given a string word, return true if the usage of capitals in it is right.

2. Examples

Example 1:

Input: word = "USA"
Output: true

Example 2:

Input: word = "FlaG"
Output: false

3. Constraints

• 1 <= word.length <= 100
• word consists of lowercase and uppercase English letters.

4. References

来源：力扣（LeetCode） 链接：https://leetcode-cn.com/problems/detect-capital 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

5. Solutions

class Solution {
  public boolean detectCapitalUse(String word) {
    if (word.equals(word.toUpperCase()) || word.equals(word.toLowerCase())) {
      return true;
    }

    if (word.length() > 1 && Character.isUpperCase(word.charAt(0))) {
      for(int i = 1; i < word.length(); i++) {
        if (Character.isUpperCase(word.charAt(i))) {
          return false;
        }
      }
      return true;
    }

    return false;
  }
}