--- /dev/null
+#!/usr/bin/perl -w
+
+use v5.36;
+use strict;
+
+$_ = <>;
+my @moves = /(\S)/g;
+
+my @units = (
+ [ [0, 0], [1, 0], [2, 0], [3, 0] ], # horiz i
+ [ [0, 1], [1, 1], [2, 1], [1, 0], [1, 2] ], # x
+ [ [0, 0], [1, 0], [2, 0], [2, 1], [2, 2] ], # v
+ [ [0, 0], [0, 1], [0, 2], [0, 3] ], # vert i
+ [ [0, 0], [0, 1], [1, 0], [1, 1] ], # o
+);
+
+my @map;
+my $w = 7;
+my $h = 0;
+
+my $units = 0;
+my $move = 0;
+
+sub can_move($unit, $vect) {
+ # say "can_move $vect->[0] $vect->[1]";
+ for my $pt (@$unit) {
+ my @dst = ($pt->[0] + $vect->[0], $pt->[1] + $vect->[1]);
+ return 0 if $dst[0] < 0 || $dst[0] >= $w;
+ return 0 if $dst[1] < 0;
+ return 0 if $map[$dst[1]][$dst[0]];
+ }
+ return 1;
+}
+
+sub dump_map {
+ for my $y (reverse 0 .. $h) {
+ for my $x (0 .. $w-1) {
+ print $map[$y][$x] ? '#' : ' ';
+ }
+ print "\n";
+ }
+ say "---- $h ----";
+}
+
+while ($units < 2022) {
+ my $u = $units[$units % @units];
+ my ($x, $y) = (2, $h+3);
+ while (1) {
+ my $m = $moves[$move++];
+ $move = 0 if $move > $#moves;
+ if ($m eq '>') {
+ $x++ if can_move($u, [$x+1, $y]);
+ } else {
+ $x-- if can_move($u, [$x-1, $y]);
+ }
+ if (can_move($u, [$x, $y-1])) {
+ $y--;
+ next;
+ }
+ last;
+ }
+ for my $pt (@$u) {
+ $map[$y + $pt->[1]][$x + $pt->[0]] = 1;
+ $h = 1 + $y + $pt->[1] if $h < 1 + $y + $pt->[1];
+ }
+ # dump_map();
+ $units++;
+}
+
+say $h;