1// run
2
3// Copyright 2009 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Solve the 2,3,5 problem (print all numbers with 2, 3, or 5 as factor) using channels.
8// Test the solution, silently.
9
10package main
11
12type T chan uint64
13
14func M(f uint64) (in, out T) {
15	in = make(T, 100)
16	out = make(T, 100)
17	go func(in, out T, f uint64) {
18		for {
19			out <- f*<-in
20		}
21	}(in, out, f)
22	return in, out
23}
24
25
26func min(xs []uint64) uint64 {
27	m := xs[0]
28	for i := 1; i < len(xs); i++ {
29		if xs[i] < m {
30			m = xs[i]
31		}
32	}
33	return m
34}
35
36
37func main() {
38	F := []uint64{2, 3, 5}
39	var n = len(F)
40	OUT := []uint64{
41		2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 25, 27, 30, 32, 36,
42		40, 45, 48, 50, 54, 60, 64, 72, 75, 80, 81, 90, 96, 100, 108, 120, 125,
43		128, 135, 144, 150, 160, 162, 180, 192, 200, 216, 225, 240, 243, 250,
44		256, 270, 288, 300, 320, 324, 360, 375, 384, 400, 405, 432, 450, 480,
45		486, 500, 512, 540, 576, 600, 625, 640, 648, 675, 720, 729, 750, 768,
46		800, 810, 864, 900, 960, 972, 1000, 1024, 1080, 1125, 1152, 1200, 1215,
47		1250, 1280, 1296, 1350, 1440, 1458, 1500, 1536, 1600}
48
49	x := uint64(1)
50	ins := make([]T, n)
51	outs := make([]T, n)
52	xs := make([]uint64, n)
53	for i := 0; i < n; i++ {
54		ins[i], outs[i] = M(F[i])
55		xs[i] = x
56	}
57
58	for i := 0; i < len(OUT); i++ {
59		for i := 0; i < n; i++ {
60			ins[i] <- x
61		}
62
63		for i := 0; i < n; i++ {
64			if xs[i] == x {
65				xs[i] = <-outs[i]
66			}
67		}
68
69		x = min(xs)
70		if x != OUT[i] {
71			println("bad: ", x, " should be ", OUT[i])
72			panic("235")
73		}
74	}
75}
76