func mergeSort(r []int) []int { length := len(r) if length <= 1 { return r } num := length / 2 left := mergeSort(r[:num]) right := mergeSort(r[num:]) return merge(left, right)}func merge(left, right []int) (result []int) { l, r := 0, 0 for l < len(left) && r < len(right) { if left[l] < right[r] { result = append(result, left[l]) l++ } else { result = append(result, right[r]) r++ } } result = append(result, left[l:]) result = append(result, right[r:]) return}