Here is the code:

package main

import "fmt"

func anon(n []int, sl []int, result [][]int) {
    if len(n) == 0 {
        result = append(result, sl)
        fmt.Printf("result %v\n", result)
        return
    }
    for i , _ := range n {
        fmt.Printf(" n %v\n", n)
        sl = append(sl, n[i])
        ab := append(n[:i], n[i 1:]...)
        fmt.Printf("i %v ---ab %v, sl %v, result %v ---\n",i, ab,sl,result )

        anon(ab, sl , result)
    }
}

func permute(nums []int) [][]int {
    var sl1 = []int{}
    var result = [][]int{}
    anon(nums, sl1, result)
 return result
}

func main() {
  sl2 := []int{1,2}
  permute(sl2)
  
}

I am expecting 'result' as [[1,2], [2,1]]. However, when I look at the below output from the code run:

 n [1 2]
i 0 ---ab [2], sl [1], result [] ---
 n [2]
i 0 ---ab [], sl [1 2], result [] ---
result [[1 2]]

n [2 2]

i 1 ---ab [2], sl [1 2], result [] ---

 n [2]
i 0 ---ab [], sl [1 2 2], result [] ---
result [[1 2 2]]

I see for (in bold) i=1, I have ab[2], sl[1 2], result[] and n[2,2]. I am not able to get it working for Golang. Something similar works well with Python.

Thanks for answering.

CodePudding user response：

Check this complete sample, which can help you to understand better how to make a permutation with golang: https://go.dev/play/p/JKG_FtilQCz.

In Golang slices are pointers to arrays, and when you make append(n[:i], n[i 1:]...) you are adding a new value in variable n, so you are changing the initial sl2 value, that should be {1,2} but is transformed in {2,2} as you noted. Try not to append in n, instead append in ab or something else.