<?php

$arr1 = [2,2,3,4,7];
$arr2 = [-1,1,2,8,10];
$merged_arr = [];
$i = 0; $j = 0;

$count_arr1 = count($arr1);
$count_arr2 = count($arr2);

$total_elements =  $count_arr1 + $count_arr2;

for($tcount = 0; $tcount < $total_elements; $tcount++){
    
    if($i >= $count_arr1){
        array_push($merged_arr, $arr2[$j]);
         $j++;
    }else if($j >= $count_arr2){
        array_push($merged_arr, $arr1[$i]);
        $i++;
    }else if($arr1[$i] >= $arr2[$j]){
        array_push($merged_arr, $arr2[$j]);
        $j++;
    }else{
        array_push($merged_arr, $arr1[$i]);
        $i++;
    }
}

print'<pre>';print_r($merged_arr);