题解 | #字符个数统计#

<?php
$str = str_replace(array("\n", "\r", "\n\r"), '', trim(fgets(STDIN)));
$len = strlen($str);
$arr = array();
$b = 0;
for($i = 0; $i < $len; $i++) {
    if (!in_array($str[$i], $arr)) {
        $arr[] = $str[$i];
        //$b++;
    }
}
//echo $b;
echo count($arr);