leetcode FirstUniqueCharacterinaString

import java.util.HashMap;

public class FirstUniqueCharacterinaString {
  /**
   * 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.
   *
   * @param s
   * @return
   */
  public int firstUniqChar(String s){
    int[] l = new int[26];
    for (char c: s.toCharArray()){
      l[c-'a'] ++;
    }

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