387-First-Unique-Character-in-a-String.js

/**
 * https://leetcode.com/problems/first-unique-character-in-a-string/description/
 * Difficulty:Easy
 *
 * 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 {string} s
 * @return {number}
 */
var firstUniqChar = function (s) {

    for (var i = 0; i < s.length; i++) {
        var ch = s[i];
        if (s.lastIndexOf(ch) === s.indexOf(ch)) return i;
    }
    return -1;
};

console.log(firstUniqChar('leetcode'));
console.log(firstUniqChar('loveleetcode'));