<?php
error_reporting(-1);
mb_internal_encoding('utf-8');
 
$text        = "сказка";
$resultTrue  = 'палиндром';
$resultFalse = 'не палиндром';
 
$text = str_replace(" ", "", $text);
$text = mb_strtolower($text);
 
 
$length     = mb_strlen($text);
$halgLength = floor($length / 2);
 
for ($i = 0; $i < $halgLength; $i++) {
    $symbol1 = mb_substr($text, $i, 1);
    $symbol2 = mb_substr($text, -$halgLength + $i, 1);
}
 
 
if ($symbol1 == $symbol2) {
    echo "$resultTrue \n";
} else {
    echo "$resultFalse \n";
} 

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