golang歸併排序算法

package algorithm

func merge(a []int, p int, q int, r int) {
	L := make([]int, q-p+1)
	R := make([]int, r-q)

	for i := 0; i < len(L); i++ {
		L[i] = a[i+p]
	}

	for i := 0; i < len(R); i++ {
		R[i] = a[i+q+1]
	}

	L = append(L, 0x7FFFFFFF)
	R = append(R, 0x7FFFFFFF)

	i := 0
	j := 0

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

func MergeSort(a []int, p int, q int) {
	if p < q {
		m := (p + q) / 2
		MergeSort(a, p, m)
		MergeSort(a, m+1, q)
		merge(a, p, m, q)
	}
}