merge sort in go

mergeSort.go

// Merge Sort Go, Ian Taylor 2017
// A very simple mergesort implementation, emphasizing algorithmic clarity over optimization

package main

import (
	"fmt"
)

// sort an unsorted array in ascending order
func mergeSort(A []int) []int {
	if len(A) <= 1 {
		return A
	} else {
		A = merge(mergeSort(A[:len(A)/2]), mergeSort(A[len(A)/2:]))
	}
	return A
}

// merge two ordered arrays, return an ordered array
func merge(A []int, B []int) []int {

	size := len(A) + len(B)
	C := make([]int, size, size)

	for i, j, k := 0, 0 ,0; k < size; k += 1 {

		// check indices of A and B for out of bounds
		if i >= len(A) {
			copy(C[k:], B[j:])
			return C
		} else if j >= len(B) {
			copy(C[k:], A[i:])
			return C
		}

		// make the comparison and merge
		if A[i] < B[j] {
			C[k] = A[i]
			i += 1
		} else {
			C[k] = B[j]
			j += 1
		}
	}
	return C
}



func main() {

	a := []int{1, 4, 7, 9, 14}
	b := []int{2, 3, 10, 12, 18, 22, 33}

	fmt.Println("a: ", a)
	fmt.Println("b: ", b)
	fmt.Println("merge: ", merge(a, b), "\n")

	c := []int{13, 48, 1, 4, -4, -3, 20, 0, 0, 100, 99, 11, 3, 7}
	fmt.Println("unsorted: ", c)
	fmt.Println("mergeSort: ", mergeSort(c))
}