function collatz($pos)
{
print $pos . "\n";
if ($pos == 1) {
exit(0);
} else {
if ($pos % 2 == 0) {
collatz($pos / 2);
} else {
collatz(3 * $pos + 1);
}
}
}
function genChain($num)
{
global $chains, $longest, $length;
$x = $num;
$chains[$x] = $num;
$num = collatz($num);
while ($num != 1) {
if (isset($chains[$num])) {
$chains[$x] .= "." . $chains[$num];
$num = 1;
} else {
$chains[$x] .= "." . $num;
$num = collatz($num);
}
}
$len = strlen($chains[$x]);
if ($len > $length) {
$length = $len;
$longest = $x;
}
}
} else {
$next = 3 * $current + 1;
}
return $next;
}
function collatz($seed)
{
$length = 1;
$next = nextCollatz($seed);
while ($next > 1) {
$next = nextCollatz($next);
$length += 1;
}
return $length + 1;
}
echo "<a href='https://projecteuler.net/problem=14'>Project Euler - Problem 14</a>";
echo "<br>";
echo "<br>";
$lengths = array();
$start = 77031;
for ($i = $start; $i < 1000000; $i++) {
$seed = $i;
$lengths[] = collatz($seed);
}
$max = max($lengths);
echo "integer with longest sequence: " . ($start + array_search($max, $lengths));
echo "<br>";
echo "length of longest sequence: " . $max;
?>
echo "{$number} ";
}
echo "<hr>";
function collatz($val)
{
(yield $val);
while ($val != 1) {
if ($val % 2 == 0) {
$val /= 2;
} else {
$val = 3 * $val + 1;
}
(yield $val);
}
}
foreach (collatz(11) as $c) {
echo $c, " ";
}
//11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
echo "Note how the output values are calculated on the fly and not stored in any array<hr>";
function to_html_list($input)
{
foreach ($input as $val) {
(yield "<li>" . $val . "</li>");
}
}
$arr = array("lorem", "ipsum", "dolor");
foreach (to_html_list($arr) as $val) {
echo $val, "\n";
}
//This will write out