Easy 387题 First Unique Character in a String

Question:

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.

Examples:

s = "leetcode"
return 0.

s = "loveleetcode",
return 2.

Solution:

public class Solution {
public int firstUniqChar(String s) {
int[] freq= new int[26];
for(int i=0;i<=s.length()-1;i++){
freq[s.charAt(i)-'a']++;
}
for(int i=0;i<=s.length()-1;i++){
if(freq[s.charAt(i)-'a']==1)
return i;
}
return -1;
}
}