217. Contains Duplicate

class Solution {

    /**
     * @param Integer[] $nums
     * @return Boolean
     */
    function containsDuplicate($nums) {
        $targets = [];
        foreach($nums as $num){
            $targets[$num] ??= 0;
            ++$targets[$num];
            if ($targets[$num] > 1){
                return true;
            }
        }

        return false;
    }
}