> For the complete documentation index, see [llms.txt](https://lfool.gitbook.io/leetcodenote/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lfool.gitbook.io/leetcodenote/30-day-leetcoding-challenge/2020-05/first-unique-character-in-a-string.md).

# First Unique Character in a String

## Description

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.

**Note:** You may assume the string contain only lowercase letters.

## code

```java
class Solution {
    public int firstUniqChar(String s) {
        for (int i = 0; i < s.length(); i++) {
            if (s.substring(i + 1).indexOf(s.charAt(i)) == -1 && 
                    s.substring(0, i).indexOf(s.charAt(i)) == -1) {
                return i;
            }
        }
        return -1;
    }
}
```