- max: documentation ( source)
- strtolower: documentation ( source)
- ord: documentation ( source)
<?php
function consecutiveCharCount($string)
{
$lcString = strtolower($string);
$prevChar = $lcString[0];
$currentLen = 0;
$maxLen = 0;
$ascending = null;
for ($i = 1; $i < strlen($lcString); $i++) {
$diff = ord($lcString[$i]) - ord($prevChar);
if ($diff == 1) {
if ($ascending !== true) {
$ascending = true;
$currentLen = 0;
}
$currentLen += 1;
} elseif ($diff == -1) {
if ($ascending !== false) {
$ascending = false;
$currentLen = 0;
}
$currentLen += 1;
} else {
$currentLen = 0;
}
$maxLen = max($maxLen, $currentLen);
$prevChar = $lcString[$i];
}
return $maxLen;
}
echo consecutiveCharCount("abcdegionoas");
echo consecutiveCharCount("EDCb00808asabc");
echo consecutiveCharCount("asg7898");
echo consecutiveCharCount("asgab876567asfon");