fun next_permutation do
		var first = p[1]
		p[1] = p[0]
		p[0] = first

		var i = 1
		count[i] += 1
		while count[i] > i do
			count[i] = 0
			i += 1

			p[0] = p[1]
			var next = p[0]

			for j in [1..i[ do p[j] = p[j+1]
			p[i] = first
			first = next

			count[i] += 1
		end
	end