00 | Two Sum

Question

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

Answer

 class Solution {

     /**
      * @param Integer[] $nums
      * @param Integer $target
      * @return Integer[]
      */
     public function twoSum($nums, $target) {
         $res = [];
         for($i=0; $i<count($nums); $i++) {
             for($j=$i+1; $j<count($nums); $j++) {
                 if($nums[$i]+$nums[$j] === $target) {
                     array_push($res, $i);
                     array_push($res, $j);
                 } else {
                     continue;
                 }
             }
         }
         return $res;
     }
 }

这是我想到的方案，the least efficient solution.