Merge sort

package main

import (
	"fmt"
	"math"
    "sync"
)

func merger(list []int, p uint, q uint, r uint) {

	var L []int
	var R []int

	L = append(L, list[p:q+1]...)
	L = append(L, math.MaxInt)

	R = append(R, list[q+1:r+1]...)
	R = append(R, math.MaxInt)

	i := 0
	j := 0
	for k := p; k <= r; k++ {
		if L[i] < R[j] {
			list[k] = L[i]
			i++
		} else {
			list[k] = R[j]
			j++
		}
	}

}

func merge(list []int, p uint, r uint) {

	var wg sync.WaitGroup
	wg.Add(2)

	if p < r {

		q := (p + r) / 2

		go func() {
			merge(list, p, q)
			wg.Done()
		}()

		go func() {
			merge(list, q+1, r)
			wg.Done()
		}()

		wg.Wait()
		merger(list, p, q, r)

	}

}

func mergeSort(list []int) {
	merge(list, 0, uint(len(list)-1))
}

func main() {

	a := []int{2, 1, 3, 5, -4, -4, 6, -8, 7, 0}

    // O(nlogn)
	mergeSort(a)

	fmt.Println(a)

}