<?php
ini_set('max_execution_time', 30);
$time_start = microtime(true);
//////////////////////////////////////////////////////
#Largest product in a grid - Problem 11
function factorial_sum($n)
{
$sum = 1;
for ($i = $n; $i >= 1; $i--) {
$sum = bcmul($sum, $i);
}
$sum = array_sum(str_split($sum));
return $sum;
}
echo $sum = factorial_sum(100);
//////////////////////////////////////////////////////////////////////
// End of execution time calculation
$time_end = microtime(true);
$execution_time = $time_end - $time_start;
//total execution time
/////////////////////////////////////////////////////////////////////
//Below Outputs the execution time in seconds
echo '<br /><br /><b>Total Execution Time:</b> ' . $execution_time . ' seconds';
function factorial_sum($n, &$total)
{
$sum = 0;
$factorials = str_split($n);
$count = count($factorials);
for ($i = 0; $i < $count; $i++) {
$p = 1;
$j = $factorials[$i];
for ($j = $j; $j > 0; $j--) {
$p *= $j;
}
$sum += $p;
}
if ($sum == $n) {
$total += $sum;
}
return $total;
}
$total = 0;
for ($i = 3; $i < 100000; $i++) {
$total = factorial_sum($i, $total);
}
echo $total;
//////////////////////////////////////////////////////////////////////
// End of execution time calculation
$time_end = microtime(true);
$execution_time = $time_end - $time_start;
//total execution time
/////////////////////////////////////////////////////////////////////
//Below Outputs the execution time in seconds
echo '<br /><br /><b>Total Execution Time:</b> ' . $execution_time . ' seconds';