LeetCode 387. First Unique Character in a String

题目

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

题意

在字串中，找出第一个不重复的字元。

Example :

s = "leetcode"
return 0.

s = "loveleetcode"
return 2.

解题想法

如果是唯一值的话，从头搜寻的索引值会等於从尾搜寻的索引值。

Solution

var firstUniqChar = function(s) {
  for (let i = 0; i < s.length; i++) {
    if (s.indexOf(s.charAt(i)) === s.lastIndexOf(s.charAt(i))) {
      return i;
    }
  }
  return -1;
};