<?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);
 
$length     = mb_strlen($text);
$halfLength = floor($length / 2);
 
for ($i=0,$n=($length-1); $i < $halfLength; $i++,$n--) {
    $symbol  = mb_substr($text, $i, 1);
    $symbol1 = mb_substr($text, $n, 1);
    if ($symbol == $symbol1) {
        $result = $result;
    } else {
        $result = 'не палиндром';
        break;
    }
}
echo "Результат: {$result}";

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