Add 521_longest_uncommon_subsequence_one

Author: m3xw3ll

Algorithms/521_longest_uncommon_subsequence_one.md

@@ -0,0 +1,40 @@
+# [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.
+```
+Solution
+```python
+class Solution:
+    def findLUSlength(self, a: str, b: str) -> int:
+        if a == b:
+            return -1
+        return max(len(a), len(b))
+        
+```

Algorithms/snippets/521_longest_uncommon_subsequence_one.py

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+def find_lus_length(a, b):
+    if a == b:
+        return -1
+    return max(len(a), len(b))
+
+
+print(find_lus_length(a="aba", b="cdc"))

README.md

@@ -148,6 +148,7 @@ To search for a specific problem please use ```STRG + F``` to search for.
 |506|[Relative Ranks](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/506_relative_ranks.md)|
 |509|[Fibonacci Number](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/509_fibonacci_number.md)|
 |520|[Detect Capital](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/520_detect_capital.md)|
+|521|[Longest Uncommon Subsequence I](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/521_longest_uncommon_subsequence_one.md)|
 |541|[Reverse String II](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/541_reverse_string_2.md)|
 |551|[Student Attendance Record I](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/551_student_attendance_1.md)|
 |557|[Reverse Words in a String III](https://github.com/m3xw3ll/LeetCode/blob/master/Algorithms/557_reverse_words_in_a_string_3.md)|