以下合并排序算法有什么问题？

Question

As the question states, I'm having trouble finding where is the issue within the following algorithm. It is the aux function for mergesort, i.e. the one used for combining sorted arrays.

func Merge(toSort *[]int, p, q, r int) {
    arr := *toSort
    L := arr[p:q]
    R := arr[q:r+1]
    fmt.Println(L)
    fmt.Println(R)
    i := 0
    j := 0

    for index := p; index <= r; index++ {
        if i >= len(L) {
            arr[index] = R[j]
            j += 1
            continue
        } else if j >= len(R) {
            arr[index] = L[i]
            i += 1
            continue
        }

        if L[i] > R[j] {
            fmt.Println("right smaller")
            arr[index] = R[j]
            j += 1
            continue
        }
        if L[i] <= R[j] {
            fmt.Println("left smaller")
            arr[index] = L[i]
            i += 1
            continue
        }

    }

}

For arr := []int{1,7,14,15,44,65,79,2,3,6,55,70} it gives as output [1 2 2 2 2 2 2 2 3 6 55 70].

Golang Play link

The JavaScript equivalent for this function works as expected, but I don't know why it isn't working in Go

Thank you

Answer 1

Golang slices are passed by reference. So you don't need to pass a pointer into the function in the first place, but you do need to take explicit copies of L and R or else merge into a different slice entirely. You are currently writing into the same underlying memory from which you are getting your values.