2022/day06.awk


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function repeats(s, i) {
	for (i = 1; i <= length(s); i++) {
		for (j = i+1; j <= length(s); j++) {
			if (substr(s, i, 1) == substr(s, j, 1)) return 1;
		}
	}
	return 0;
}
{
	for (i = 1; i <= length; i++) {
		c1 = c2;
		c2 = c3;
		c3 = c4;
		c4 = substr($1, i, 1);
		if (c1 == c2 || c1 == c3 || c1 == c4) continue;
		if (c2 == c3 || c2 == c4) continue;
		if (c3 == c4) continue;
		if (i < 4) continue;
		print i;
		break;
	}
	for (i = 1; i+14 <= length; i++) {
		s = substr($1, i, 14);
		if (repeats(s)) continue;
		print 13+i;
		break;
	}
}