AoC 2022, day 6

sub run-tests() {
    use Test;

    is sig-start('bvwbjplbgvbhsrlpgdmjqwftvncz', 4),       5, "'bvwbjplbgvbhsrlpgdmjqwftvncz', length 4, start at 5";
    is sig-start('nppdvjthqldpwncqszvftbrmjlhg', 4),       6, "'nppdvjthqldpwncqszvftbrmjlhg', length 4, start at 6";
    is sig-start('nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg', 4), 10, "'nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg', length 4, start at 10";
    is sig-start('zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw', 4),  11, "'zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw', length 4, start at 11";

    is sig-start('mjqjpqmgbljsphdztnvjfqwrcgsmlb', 14),    19, "'zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw', length 14, start at 19";
    is sig-start('bvwbjplbgvbhsrlpgdmjqwftvncz', 14),      23, "'bvwbjplbgvbhsrlpgdmjqwftvncz', length 14, start at 23";
    is sig-start('nppdvjthqldpwncqszvftbrmjlhg', 14),      23, "'nppdvjthqldpwncqszvftbrmjlhg', length 14, start at 23";
    is sig-start('nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg', 14), 29, "'nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg', length 14, start at 29";
    is sig-start('zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw', 14),  26, "'zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw', length 14, start at 26";

    done-testing;
}

sub sig-start(Str:D \str, UInt:D \len --> UInt:D) {
    my @S = str.comb;
    (^@S).first({ +@S[$_ .. $_+len-1].Set == len }) + len
}

run-tests;
put '';

my \str = $*IN.slurp;
put 'part 1: ', sig-start(str, 4);
put 'part 2: ', sig-start(str, 14);