<?php
error_reporting(-1);
mb_internal_encoding("UTF-8");
 
$text = "А роза упала на лапу азора";
$result = "палиндром";
 
$text = mb_strtolower($text);
$text = str_replace(" ", "", $text);
 
$lenght = mb_strlen($text);
$halfLenght = floor($lenght/ 2);
 
for ($i = 0, $u = -1; $i < $halfLenght; $i++, $u--) {
	$stroka1 = mb_substr($text, $i, 1);
	$stroka2 = mb_substr($text, $u, 1);
 
	if ($stroka1 != $stroka2) {
		$result = "не палиндром";
		break;
	}
}
 
echo $result;

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