Detect Capital.md

Algorithm

Use a "regular expression" (regex) by using .matches().

• [] around a 'set' of characters is a match if any of the characters match.
  • [A-Z] matches any character from A to Z.
• * means 0 or more of whatever precedes it
• | means "or"
• . matches any character

Solution

class Solution {
    public boolean detectCapitalUse(String word) {
        if (word == null) {
            return false;
        }
        return word.matches("[A-Z]*|.[a-z]*");
    }
}

Time/Space Complexity

• Time Complexity: O(n)
• Space Complexity: O(1)

Links

• github.com/RodneyShag