521 Longest Uncommon Subsequence I

1. Description

Given two strings a and b, return the length of the longest uncommon subsequence between a and b. If the longest uncommon subsequnece does not exist, return -1.

 

An uncommon subsequence between two strings is a string that is subsequence of one but not the other.

 

A subsequence of a string s is a string that can be obtained after deleting any number of characters from s. For example, "abc" is a subsequence of "aebdc" because you can delete the underlined characters in "aebdc" to get "abc". Other subsequences of "aebdc" include " aebdc", "aeb", and "" (empty string).

 

constraints :

• 1 <= a.length, b.length <= 100
• a and b consist of lower-case English letters.

 

2. Algorithms

1. Start
2. Return -1 if a is same with b.
3. Return max length between a and b.
4. End

I can't understand examples of this problem how algorithm get the output.

3. Codes

class Solution:
    def findLUSlength(self, a: str, b: str) -> int:
        if a == b : return -1 
        return max(len(a), len(b))

4. Conclusion