520. Detect Capital

Easy

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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

Constraints:

• 1 <= word.length <= 100

• word consists of lowercase and uppercase English letters.

class Solution:
    def detectCapitalUse(self, word: str) -> bool:
        one_small = False
        one_caps = False
        first_capital = True
        for index, char in enumerate(word):
            if index == 0 and char.isupper():
                first_capital = True
            elif char.isupper() and one_small:
                return False
            elif char.islower() and one_caps:
                return False
            elif char.islower():
                one_small = True
            elif char.isupper():
                one_caps = True
        return True