原題鏈接-Easy

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

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

時間復(fù)雜度: O(N)- 空間復(fù)雜度: O(N)

<?php
print_r(test([11,2,7,15], 9));

function test($nums, $target) {
    $lookup[$nums[0]] = 1;
    foreach ($nums as $key=>$num) {
        // code...
        if (in_array($target - $num, $nums)) {
            // code...
            return [array_search($target-$num,$nums),$key];
        }else {
            $lookup[$num] = $key;
        }
    }
}