算法：两个有序数组合并为一个有序数组

https://github.com/Alexchent/interview/blob/master/array_merge_sort.php

function array_merge_sort($a, $b)
{
    $an = count($a);
    $bn = count($b);
    $i = 0;
    $j =0 ;
    $result = [];
    while (1) {
        if (!isset($a[$i])) {
                for ($j; $j < $bn; $j++) {
                    $result[] = $b[$j];
                }
                break;
        }

        if (!isset($b[$j])) {
            for ($i; $i < $an; $i++) {
                $result[] = $a[$i];
            }
            break;

        }

        if ($a[$i] < $b[$j]) {
                $result[] = $a[$i];
                echo 'i——',$i."\n";
                $i++;
        } else {
                $result[] = $b[$j];
                echo 'j——',$j."\n";
                $j++;
        }
    }
    return $result;
}