387. First Unique Character in a String

JIAKAOBO

LeetCode

感谢赞助!

• ㊗️
• 大家
• offer
• 多多！

Problem

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

Examples:

s = "leetcode"
return 0.

s = "loveleetcode"
return 2.

Code

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

        for(int i = 0; i < s.length(); i ++){
            if(freq [s.charAt(i) - 'a'] == 1){
                return i;
            }
        }

        return -1;
    }
}