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Question

Let's categorize this for PHP only.

Ok so I had an interview yesterday for a Senior Software Developer role. I can't remember the question very well but I try to write it as much as I remember.

Question;

Write a function that takes a string as the input and return true if traversed, false if not.

Requirements; (as much as I remember) - Only one input (string) type.
- String param must be passed by reference.
- No variable within the function, he means that if the param is called $str manipulation should be done on that, didn't like me to use a second variable to set reverseStr etc.
- No looping every character in the string, he specifically said not to loop thru every character in the string.
- No Built-in PHP function can be used, i think he was fine with (strlen)

My Answer; (nope he didn't like it)

$str = 'this is testing';
$length = strlen($str);
$reverseStr = '';
for($i=$length-1; $i>=0; $i--) {
 $reverseStr .= $str[$i];
}

So while this does the job somewhat, he didn't like me to go thru every character to get the reverseStr. I am guessing I needed to think about a recursive solution get the last character of the string and index etc.etc. but I am thinking about these as I am writing this, too late!

What you guys thinking?

Answer 1

the question isn't clear at all.. but if you want to check if the string is a palindrome:

function is_palindrome ($str){
    if(strlen($str)==0){return true;}
    if($str[0]==$str[strlen($str)-1]){
        return true and is_palindrome(substr($str, 1, strlen($str)-2));
    }else{
        return false;
    }
}