DER BIMMLER
1) {
$tailn += ($distance <=> 0);
}
}
/* ---------- */
/* ---H---1H- */
/* -1----2--- */
/* -2-------- */
function move_tail(&$head, &$tail, $tailnr, $i) {
print(strval($i)."-".strval($tailnr)."Head: ");
print_pos($head);
print(": ");
print_pos($tail);
$dx = $head[0] - $tail[0];
$dy = $head[1] - $tail[1];
if (abs($dx) > 2 || abs($dy) > 2) {
exit(1);
}
if (abs($dx) == 2) { // move both
if (abs($dy) >= 1) {
$tail[1] += ($dy <=> 0);
}
$tail[0] += ($dx <=> 0);
}
else if (abs($dy) == 2) {
if (abs($dx) >= 1) {
$tail[0] += ($dx <=> 0);
}
$tail[1] += ($dy <=> 0);
}
/* move_number_closer($head[0], $tail[0]); */
/* move_number_closer($head[1], $tail[1]); */
print("->");
print_pos($tail);
print("
");
}
function print_pos($pos) {
print("[".strval($pos[0]).",".strval($pos[1])."]");
}
$display_lines = array();
function display($head, $tail) {
ob_clean();
$req_size_x = max($head[0], $tail[0]);
$req_size_y = max($head[1], $tail[1]);
for ($y = 0; $y < $req_size_y; $y++) {
$display_lines[$y] = str_repeat('.', $req_size_x);
}
$display_lines[$head[1]][$head[0]] = "H";
$display_lines[$tail[1]][$tail[0]] = "T";
for ($y = 0; $y < count($display_lines); $y++) {
print($display_lines[$y]."
");
}
}
$filename = "ropes.txt";
/* $filename = "test2.txt"; */
$ropefile = fopen($filename, "r");
$input = fread($ropefile, filesize($filename));
$head_movements = explode("\n", $input);
fclose($ropefile);
$visited_positions = array("0_0" => 0);
$current_positions = array_fill(0, 10, [0, 0]);
for ($i = 0; $i < count($head_movements); $i++) {
/* print($head_movements[$i]); */
$direction = $head_movements[$i][0];
$amount = (int) substr($head_movements[$i], 2);
for ($a = 0; $a < $amount; $a++) {
// move head
switch ($direction) {
case "L":
$current_positions[0][0] -= 1;
break;
case "R":
$current_positions[0][0] += 1;
break;
case "U":
$current_positions[0][1] += 1;
break;
case "D":
$current_positions[0][1] -= 1;
break;
}
// move tails
for ($t = 1; $t < count($current_positions); $t++) {
move_tail($current_positions[$t-1], $current_positions[$t], $t, $i);
}
$last_tail = count($current_positions) - 1;
$visited_positions[strval($current_positions[$last_tail][0])."_".strval($current_positions[$last_tail][1])] += 1;
/* display($current_positions[0], $current_positions[$last_tail]); */
}
}
print_r($visited_positions);
print("Total number of positions=".array_sum($visited_positions));
print("Number of unique visited positions=".count($visited_positions));