## Algorithm

Problem Name: 521. Longest Uncommon Subsequence I

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.

## Code Examples

### #1 Code Example with C Programming

```Code - C Programming```

``````
const findLUSlength = function(a, b) {
return a === b ? -1 : Math.max(a.length, b.length);
};
``````
Copy The Code &

Input

cmd
a = "aba", b = "cdc"

Output

cmd
3

### #2 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def findLUSlength(self, a, b):
"""
:type a: str
:type b: str
:rtype: int
"""
return -1 if a == b else max(len(a), len(b))
``````
Copy The Code &

Input

cmd
a = "aba", b = "cdc"

Output

cmd
3

### #3 Code Example with C# Programming

```Code - C# Programming```

``````
using System;

namespace LeetCode
{
public class _0521_LongestUncommonSubsequenceI
{
public int FindLUSlength(string a, string b)
{
if (a == b) return -1;
return Math.Max(a.Length, b.Length);
}
}
}
``````
Copy The Code &

Input

cmd
a = "aaa", b = "bbb"

Output

cmd
3