LeetCode 520. Detect Capital



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.

Example 1:

Input: word = "USA"
Output: true

Example 2:

Input: word = "FlaG"
Output: false


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


Base on the problem description and evaluate the capital usage.

Python Solution

class Solution:
    def detectCapitalUse(self, word: str) -> bool:
        upper_count = 0
        for c in word:
            if ord(c) >= ord('A') and ord(c) <= ord('Z'):
                upper_count += 1

        if upper_count == 0:
            return True
        if upper_count == len(word):
            return True
        if upper_count == 1 and ord(word[0]) >= ord('A') and ord(word[0]) <= ord('Z'):
            return True
        return False
  • Time Complexity: O(N).
  • Space Complexity: O(1).

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