0387. First Unique Character in a String
https://leetcode.com/problems/first-unique-character-in-a-string
Description
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:** 0
Example 2:
**Input:** s = "loveleetcode"
**Output:** 2
Example 3:
**Input:** s = "aabb"
**Output:** -1
Constraints:
1 <= s.length <= 105
s
consists of only lowercase English letters.
ac
class Solution {
public int firstUniqChar(String s) {
// edge case
if (s == null || s.length() == 0) return -1;
int[] note = new int[26];
for (int i = 0; i < s.length(); i++) {
note[s.charAt(i) - 'a']++;
}
for (int i = 0; i < s.length(); i++) {
if (note[s.charAt(i) - 'a'] == 1) {
return i;
}
}
return -1;
}
}
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