数组乱序
方法1.sliceOutOfOrder 选定随机数r 将下标r和下边i交换，i– ，就是和当前最后一位交换
方法2.rand.Perm(数组长度) 将原数组下标按照随机出来的数据赋值给另一数组

package main

import "fmt"
import "math/rand"
import "time"

var (
    rr = rand.New(rand.NewSource(time.Now().UnixNano()))
    a1 = [2]int{}
    a2 = [10]int{}
)

func main() {
    a := []int{0,1}
    for i := 0; i < 10000; i++ {
        randslice()
        //fmt.Println(rr.Intn(10))
        sliceOutOfOrder(a)
    }
    fmt.Println(a1)
    fmt.Println(a2)
}
func sliceOutOfOrder(in []int) []int {
    l := len(in)
    for i := l - 1; i > 0; i-- {
        r := rr.Intn(i)
        in[r],in[i] = in[i],in[r]
    }
    a1[in[0]] += 1
    return in
}

func randslice() {
    in := rr.Perm(10)
    a2[in[0]] += 1
}