Elance PHP5 code test (with answers)

February 17, 2011PHP As Is

Here is the list of problems with correct answers for Elance PHP5 Code Test:

1. recursive xml traversal:

 
function ReadXml($xmlstr)
{
    static $res = '';
    $xml = new SimpleXMLElement($xmlstr);
 
    if(count($xml->children()))
    {
        $res .= $xml->getName().PHP_EOL;
        foreach($xml->children() as $child)
        {
            ReadXml($child->asXML());
        }
    }
    else
    {
        $res .= $xml->getName().': '.(string)$xml.PHP_EOL;
    }
 
    return $res;
}

2. (sql) select the second highest id from user table:

SELECT id FROM user ORDER BY id DESC LIMIT 1,1

3. get checkbox values from POST:

    $res = array();
    while(list($checkbox,) = each($_POST))
    {
        $res[] = intval(substr($checkbox,strpos($checkbox,'_') + 1));
    }
    sort($res);
    echo implode(' ',$res);

4. get unique array elements:

 
function GetUniqueOnes($arr)
{
    $res = implode(',',array_unique($arr));
 
    return $res;
}

5. generate random password:

 
function GeneratePassword ($length,$chars)
{
    $res = '';
    $char_length = strlen($chars);
    for($i = 0; $i < $length; $i++)
    {
        $res .= $chars[rand(0,$char_length)];
    }
 
    return $res;
}

6. split email addresses:

function SplitEmailAddress($address)
{
    list($user, $domain) = explode('@',$address);
    return array('user' => $user, 'domain' => $domain);
}

7. the most challenging task (for me). Phone regexps:

function ReformatPhoneNumber($number)
{
    if (preg_match('/^(\d[ -]?){7,12}$/', $number, $matches))
    {
        return preg_replace('/[ -]/', '', $number);
    }
 
    throw new Exception('Invalid phone number');
}

8. get longest string in arguments:

function GetLongestString()
{
    $length = 0;
    foreach(func_get_args() as $arg)
    {
 
        $var = strlen($arg);
        if($var > $length)
        {
            $length = $var;
        }
    }
    return $length;
}

9. find maximum in nested array:

function MaxArray($arr)
{
    $GLOBALS['max'] = 0;
    array_walk_recursive($arr,create_function('$item,$key','if($item > $GLOBALS["max"]) $GLOBALS["max"] = $item;'));
    return $GLOBALS['max'];
}

10. output all numbers divisable by 8 from 200 to 600 inclusive:

for($i = 200; $i <= 592; $i+=8)
{
    echo $i.',';
}
echo $i;

Note, that all answers are correct, but some of them are not optimized, so you may be in top 20% with this, but not higher. If someone would like to post any improvements to the code snippets above – they are welcome:)

Ryan August 25, 2011 at 7:45 pm

function MaxArray($arr) {
$max = 0;
foreach($arr as $a) {
$tmp = (is_array($a) ? MaxArray($a) : $a;
$max = ($tmp > $max) ? $tmp : $max;
}
return $max;
}

Reply
Dorothy September 4, 2011 at 5:06 am

Very nice, i suggest webmaster can set up a forum, so that we can talk and communicate.

Reply
Andrew September 4, 2011 at 4:31 pm

function GeneratePassword($length, $chars)
{
return substr(str_shuffle($chars), 0, $length);
}

function GetLongestString()
{
return max(array_map(strlen, func_get_args()));
}

Reply
mohit September 14, 2011 at 8:41 pm

$i=200;
while($i%8!=0)
{
$i++;
}
while($i<=600)
{
echo $i;
if($i<600)
{
echo ",";
}
$i+=8;
}

Reply
neo(nickname) December 21, 2011 at 2:58 pm

hey thank you very much …….
appreciate all of your efforts 🙂

Reply
pride December 28, 2011 at 5:06 pm

function GeneratePassword($length, $chars)
{
return substr(str_shuffle($chars), 0, $length);
}

pretty good idea,but what if $length’s value is greater than strlen($chars) ？
you won’t get a 10 chars password while $chars=’abc’

Reply
admin December 28, 2011 at 5:29 pm

nice catch, pride. But then I think Andrew’s solution may be improved by

return substr(str_shuffle(str_repeat($chars,$length)), 0, $length);

right?

Reply
kievan January 4, 2012 at 11:09 pm

Not sure about the GeneratePassword() problem, but I do have a version of the ReadXml(), that I tested to be way more efficient that one in this post. Obviously it is much uglier, and much more rigid, but it runs at least 5 times as fast. Here is the screenshot from KCacheGrind analyzing xDebug profiling output: http://tinypic.com/r/b8k704/5

Here is the code:

function ReadXml($xmlstr)
{
$p = xml_parser_create();
xml_parser_set_option ($p, XML_OPTION_CASE_FOLDING, 0);
xml_parse_into_struct($p, $xmlstr, $vals);
xml_parser_free($p);
return
($vals[0][‘tag’].PHP_EOL.
$vals[1][‘tag’].’: ‘.$vals[1][‘value’].PHP_EOL.
$vals[2][‘tag’].’: ‘.$vals[2][‘value’].PHP_EOL.
$vals[3][‘tag’].’: ‘.$vals[3][‘value’].PHP_EOL.
$vals[4][‘tag’].’: ‘.$vals[4][‘value’].PHP_EOL);
}

Reply
admin January 5, 2012 at 8:35 am

Hi kievan,
thanks for your solution, hope it helps others!

Reply
kievan January 5, 2012 at 9:59 pm

I hope so too.

And thanx for this great post 🙂
I was able to score 85 for this same test on vWorker.

Used your examples while preparing for the test, saved me a good deal of time for sure 🙂

Reply
dali January 22, 2012 at 11:18 am

Hi mate, you may loose your account for posting this to public 🙂

Reply
Tester1 April 23, 2012 at 7:07 am

Sorry for that ugly name, also results worked fine, bud kievan reply about XML DONT works. Thanks dudes 🙂

Reply
enrique barchiesi July 4, 2012 at 3:50 pm

The second response is wrong you need to do a double query there.
SELECT MAX(id) FROM user WHERE id NOT IN (SELECT MAX(id) FROM user )
Something similar i din´t tested it but it must work.

Reply
Shehan July 20, 2012 at 6:24 pm

I passed this test on elance and I was top 10%

Reply
Faisal August 21, 2012 at 8:31 pm

for($i=200;$i<=600;$i++){
if(($i % 8) === 0){
echo $i;
if($i != 600){echo ",";}
}

}

Reply
Faisal August 22, 2012 at 3:42 am

function GetLongestString(){
global $maxlength;
$numofargs = func_num_args();
for($i=0;$i<$numofargs;$i++){
$string = func_get_arg($i);
$length = strlen($string);
if($maxlength < $length){
$maxlength = $length;
}
}
return $maxlength;
}

What is the wrong with this code??

Reply
Faisal August 22, 2012 at 3:45 am

function MaxArray($arr){
$length = count($arr);
global $maxValue;
for($i=0;$i<$length;$i++){
if(is_int($arr[$i])){
//count maximum value
if($maxValue < $arr[$i]){
$maxValue = $arr[$i];
}
//end counting
}
elseif(is_array($arr[$i])){
MaxArray($arr[$i]);
}
}
return $maxValue;
}

Additionally I don’t find any wrong but Elance won’t except my code. Do you tell me why?

Reply
Harsh August 27, 2012 at 10:07 am

Thanks friend really I appreciate your efforts ..

Reply
Sirajus Salayhin September 17, 2012 at 7:34 pm

SELECT id, name
FROM user
WHERE id = (SELECT MAX(id) FROM user WHERE id < (SELECT MAX(id) FROM user));

Reply
Marc Donaldson September 26, 2012 at 3:59 pm

Here is my result to convert the POST values ending with underscore to a sortable array.

Based upon 10000 fields it performs 35% faster

$res = array(); foreach($_POST as $key => $value) { $res[] = intval(substr($key,strrpos($key,'_') + 1)); } sort($res); $result1 = implode(' ',$res);

Reply
Marc Donaldson September 26, 2012 at 4:28 pm

Sorry!! Please replace $result1 = with echo

Reply
admin September 26, 2012 at 4:56 pm

thanks Marc

Reply
Sirajus Salayhin October 3, 2012 at 6:47 pm

SELECT DISTINCT(id) FROM `user` WHERE `id`=(SELECT MAX(id) FROM user);

Reply
anonymous November 5, 2012 at 2:49 pm

Thanks bro you rock 🙂

Reply
Lokesh Tulsani November 29, 2012 at 8:48 am

Write a program that outputs the numbers that are divisible by 8 and are between 200 and 600 (inclusive), separated by commas (without spaces or line breaks).

<?php
$Result = array();
for($i = 200; $i

Reply
jewel December 1, 2012 at 2:53 pm

super , duper, bumper.

Reply
Faisal December 20, 2012 at 5:53 am

Your SQL is not perfect:

Right one is like this:
table name: basic_information
roll name total_marks
45 Faisal 90
46 Rasel 89
47 Adit 91
48 Sajib 91

SELECT * FROM `basic_information` WHERE `total_marks` = (SELECT DISTINCT `total_marks` FROM `basic_information` ORDER BY `total_marks` DESC LIMIT 1,1);

Reply
Ramesh March 9, 2013 at 5:52 am

Really aewsome tutorial…..

Reply
GHanta June 12, 2013 at 10:01 am

you are awesome bro

Reply
iliyas pathan September 29, 2013 at 12:28 pm

Awesome man….. 🙂

Reply
Custom Icon Design February 28, 2014 at 9:23 am

for GeneratePassword ($length,$chars) function

$char_length = strlen($chars); should be char_length =strlen($chars) -1;

Because rand(0, max) including max. but max element of array is chars[char_length -1], right?

Reply

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