How to Generate All Permutations of a List in Go?

Permutations in Go: An In-Depth Guide

This article discusses the different ways to generate all possible permutations of a list of elements in Go.

One common method is Heap's algorithm, which generates each permutation from the previous one by swapping a pair of elements. The following Go function implements this algorithm:

func permutations(arr []int)[][]int{
    var helper func([]int, int)
    res := [][]int{}

    helper = func(arr []int, n int){
        if n == 1{
            tmp := make([]int, len(arr))
            copy(tmp, arr)
            res = append(res, tmp)
        } else {
            for i := 0; i < n; i++{
                helper(arr, n - 1)
                if n % 2 == 1{
                    tmp := arr[i]
                    arr[i] = arr[n - 1]
                    arr[n - 1] = tmp
                } else {
                    tmp := arr[0]
                    arr[0] = arr[n - 1]
                    arr[n - 1] = tmp
                }
            }
        }
    }
    helper(arr, len(arr))
    return res
}

To use this function, simply pass in a slice of integers and it will return a slice of all the permutations of the input list. For example:

arr := []int{1, 2, 3}
fmt.Println(permutations(arr))

Another method of generating permutations is to use the factorial number system. This method allows for the quick generation of the nth lexicographical permutation. For more information on this method, refer to the "Permutation" section in the article above.

By implementing these methods, you can easily generate permutations in Go for use in a variety of applications.

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