go安装包中test目录235.go中的代码。知道查找这些数字的算法,但还是不知道这些数字具体的规律。有研究过的朋友吗?
```go
// run
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Solve the 2,3,5 problem (print all numbers with 2, 3, or 5 as factor) using channels.
// Test the solution, silently.
package main
import (
"fmt"
)
type T chan uint64
func M(f uint64) (in, out T) {
in = make(T, 100)
out = make(T, 100)
go func(in, out T, f uint64) {
for {
out <- f * <-in
}
}(in, out, f)
return in, out
}
func min(xs []uint64) uint64 {
m := xs[0]
for i := 1; i < len(xs); i++ {
if xs[i] < m {
m = xs[i]
}
}
return m
}
func main() {
F := []uint64{2, 3, 5}
var n = len(F)
OUT := []uint64{
2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 25, 27, 30, 32, 36,
40, 45, 48, 50, 54, 60, 64, 72, 75, 80, 81, 90, 96, 100, 108, 120, 125,
128, 135, 144, 150, 160, 162, 180, 192, 200, 216, 225, 240, 243, 250,
256, 270, 288, 300, 320, 324, 360, 375, 384, 400, 405, 432, 450, 480,
486, 500, 512, 540, 576, 600, 625, 640, 648, 675, 720, 729, 750, 768,
800, 810, 864, 900, 960, 972, 1000, 1024, 1080, 1125, 1152, 1200, 1215,
1250, 1280, 1296, 1350, 1440, 1458, 1500, 1536, 1600}
x := uint64(1)
ins := make([]T, n)
outs := make([]T, n)
xs := make([]uint64, n)
for i := 0; i < n; i++ {
ins[i], outs[i] = M(F[i])
xs[i] = x
}
for i := 0; i < len(OUT); i++ {
for i := 0; i < n; i++ {
ins[i] <- x
}
for i := 0; i < n; i++ {
if xs[i] == x {
xs[i] = <-outs[i]
}
}
fmt.Println(x, xs, ins, outs)
x = min(xs)
fmt.Println(x)
if x != OUT[i] {
println("bad: ", x, " should be ", OUT[i])
panic("235")
}
}
}
```
[Google查的](https://math.stackexchange.com/questions/197746/get-numbers-that-have-only-2-3-and-5-as-prime-factors)
看起来是计算以2,3,5为因子的数之类的吧。Google上有很多人问这个问题,而且有其他语言的实现等等。
#1