/**
* Problem: The decimal number, 585 = 10010010012 (binary), is palindromic in both bases.
*
* Find the sum of all numbers, less than one million, which are palindromic in base 10 and base 2.
*
* (Please note that the palindromic number, in either base, may not include leading zeros.)
*
* Solution:
*/
include "helper.php";
function isPalindromic($num)
{
$digits = str_split($num);
$len = count($digits);
for ($i = 0; $i < floor($len / 2); $i++) {
if ($digits[$i] != $digits[$len - $i - 1]) {
return false;
}
}
return true;
}
$total = 0;
for ($i = 1; $i < 1000000; $i++) {
if (isPalindromic($i)) {
if (isPalindromic(decbin($i))) {
$total += $i;
}
}
}
result(872187, $total);
throw new \InvalidArgumentException('$integer must be a number');
}
$integer = (int) $integer;
if ($integer < 0) {
return false;
}
if ($integer === 0) {
return true;
}
$numberOfDigits = floor(log10($integer)) + 1;
$integerRemaining = $integer;
$msdShift = pow(10, $numberOfDigits - 1);
for ($i = 0; $i < $numberOfDigits / 2; $i++) {
if ((int) ($integer / $msdShift) != (int) ($integerRemaining % 10)) {
return false;
}
$integer %= $msdShift;
$msdShift /= 10;
$integerRemaining /= 10;
}
return true;
}
$inputHelper = new InputHelper();
$integer = $inputHelper->readInputFromStdIn('Enter the integer to test: ');
$result = isPalindromic($integer);
if ($result === true) {
printf('The integer %d is palindromic', $integer);
} else {
printf('The integer %d is not palindromic', $integer);
}
print PHP_EOL;
