gistfile1.php

<?php

#Solution for calculating xy=total, x-y->0.
#y is always equal or greater than x
#Reference: http://www.wolframalpha.com/input/?i=xy%3D200,+x%3E0
function min_xy($total){
    $all_xy = array();
    
    $min = $total;//minimum number
    $min_idx = -1;//minium number position in $all_xy
    
    for($x = 1; $x <= $total; $x++){
        if(($total % $x == 0) && ($x <= ($total / $x))){
            $all_xy[] = array($x, ($total / $x));
        }
    }
    
    foreach($all_xy as $i => $xy){
        if(($xy[1] - $xy[0]) < $min){ 
            $min = $xy[1] - $xy[0];
            $min_idx = $i;
        }
    }
    
    return $all_xy[$min_idx];
}

?>