First Unique Character in a String
Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.
Example 1
Input
s = "leetcode"Output
0The character
'l' at index 0 is the first character that does not occur at any other index.Example 2
Input
s = "loveleetcode"Output
2The character
'v' at index 2 is the first character that does not occur at any other index.Constraints
- 1 <= s.length <= 10^5
- s consists of only lowercase English letters.
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