2025/11/puzzle-1.awk


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#!/usr/bin/gawk -f

function npaths(src, dst,    n, i)
{
	if (src == dst)
		return 1;
	n = 0
	for (i in paths[src])
		n += npaths(paths[src][i], dst)
	return n
}

BEGIN { FS = ":? " }

{
	for (i = 2; i <= NF; i++)
		paths[$1][i - 1] = $i
}

END { print npaths("you", "out") }