387. First Unique Character in a String
Queue, Hash Table, String, Counting ·Problem Statement
link: LeetCode.cn LeetCode
Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.
Example:
Input: s = "leetcode"
Output: 0
Input: s = "loveleetcode"
Output: 2
Input: s = "aabb"
Output: -1
Solution Approach
Algorithm
Implement
class Solution:
def firstUniqChar(self, s: str) -> int:
count = collections.Counter(s)
for i, c in enumerate(s):
if count[c] ==1:
return i
return -1