Leetcode 520

Solution 1:

This solution is pretty simple, we can make three strings then compare them to word, and see if any of them match, if they do we can return true.

The three strings that we can make are:

allCap, this is for the whole word to be upper case (ie. "LEETCODE")
allLower, this is for the whole word to be lower case (ie. "leetcode")
firstCap, this is for the whole word to be lower case except for the first letter which is uppercase (ie. "Leetcode")

func detectCapitalUse(word string) bool {
    allCap := strings.ToUpper(word)
    allLower := strings.ToLower(word)
    firstCap := strings.ToUpper(string(word[0])) + strings.ToLower(word)[1:]
    
    return word == allCap || word == allLower || word == firstCap
}

Solution 2:

The second solution uses the fact that in "leetcode" and "Leetcode" there is a common "eetcode". This means that whatever the first letter is, if the remaining part of the word is lowercase we know that all the letters in word are lowercase, or the first letter is the only letter that is upper case.

func detectCapitalUse(word string) bool {
    allCap := strings.ToUpper(word)
    remainingPart := strings.ToLower(word)[1:]
    
    return word == allCap || word[1:] == remainingPart
}