0521. Longest Uncommon Subsequence I

https://leetcode.com/problems/longest-uncommon-subsequence-i

Description

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

An uncommon subsequence between two strings is a string that is a 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).

Example 1:

**Input:** a = "aba", b = "cdc"
**Output:** 3
**Explanation:** One longest uncommon subsequence is "aba" because "aba" is a subsequence of "aba" but not "cdc".
Note that "cdc" is also a longest uncommon subsequence.

Example 2:

**Input:** a = "aaa", b = "bbb"
**Output:** 3
**Explanation:** The longest uncommon subsequences are "aaa" and "bbb".

Example 3:

**Input:** a = "aaa", b = "aaa"
**Output:** -1
**Explanation:** Every subsequence of string a is also a subsequence of string b. Similarly, every subsequence of string b is also a subsequence of string a.

Constraints:

• 1 <= a.length, b.length <= 100

• a and b consist of lower-case English letters.

ac