Hash Table

The original case/problem could be found on leedcode

case 387 (classical case) JS and PHP

var firstUniqChar = function(s) {
    // make a new hash table using new Map()
    map = new Map()
    // counting....
    for (let i = 0; i < s.length; i++) {
        word = s[i]; // it can be also a number
        val = map.get(word);
        if (map.has(word)) {
            map.set(word, val + 1)
        } else {
            map.set(word, 1)
        }
    }
    // find sth. which shows uns 1 2,or 3.... times, in this sample it is one time.
    for (let i = 0; i < s.length; i++) {
        if (map.get(s[i]) === 1) {
            return i
        }
    }
    return NaN;
};

class Solution {

    /**
     * @param String $s
     * @return Integer
     */
    function firstUniqChar($s) {
        $hashmap = []; // At php, array can be used directly as a hash table
        for ($i=0;$i<strlen($s);$i++){
            $word = $s[$i];
            if (isset($hasmap[$word])){
            $hasmap[$word] +=1;
        }
        else {
           $hasmap[$word] = 1; 
        }          
        }
        for ($i=0;$i<strlen($s);$i++){
             $word = $s[$i];
            if ($hasmap[$word] == 1){
                return $i;
            }
        }
        return "NaN";
    }
}