力扣链接：
https://leetcode-cn.com/probl...
解题思路：

  1. 回溯算法
func permute(nums []int) [][]int {    res := [][]int{}    backtrack(&res, nums, []int{})    return res}func backtrack(res *[][]int, nums, path []int) {    if len(path) == len(nums) {        // 切片内存拷贝        newPath := make([]int, len(path))        copy(newPath, path)        *res = append(*res, newPath)        return    }    for i := 0; i < len(nums); i++ {        if contains(path, nums[i]) {            continue        }        path = append(path, nums[i])        backtrack(res, nums, path)        path = path[:len(path) - 1]    }}func contains(nums []int, num int) bool {    for _, v := range nums {        if v == num {            return true        }    }    return false}