1. <?php
    2. /**
    3.  * @param array $nums
    4.  * @param int $target
    5.  * @return array [index1, index2]
    6.  */
    7. function twoSum(array $nums, int $target) : array {
    8.     $map = [];
    9.     for($i = 0; $i <= count($nums) - 1; $i++) {
    10.         $diff = $target - $nums[$i];
    11.         if (isset($map[$diff])) {
    12.             return [$map[$diff], $i];
    13.         }
    14.         $map[$nums[$i]] = $i;
    15.     }
    16.     return [0, 0];
    17. }
    19. $nums = [3, 2, 4, 4];
    20. $ret = twoSum($nums, 7);
    21. print_r($ret);