题解 | #进制转换#

<?php
fscanf(STDIN, "%s", $str);
$map = [
    '0' => 0,
    '1' => 1,
    '2' => 2,
    '3' => 3,
    '4' => 4,
    '5' => 5,
    '6' => 6,
    '7' => 7,
    '8' => 8,
    '9' => 9,
    'A' => 10,
    'B' => 11,
    'C' => 12,
    'D' => 13,
    'E' => 14,
    'F' => 15
];

$num = 0;
$basic = 16;
for($i = 2; $i < strlen($str); $i++){
    $char = $str[$i];
    $value = $map[$char];
    $num = $num * 16 + $value;
}
echo $num;