编辑代码

def merge_sort(arr):
    if len(arr) <= 1:
        return arr

    # 分解
    mid = len(arr) // 2
    left = arr[:mid]
    right = arr[mid:]

    # 递归排序
    left = merge_sort(left)
    right = merge_sort(right)

    # 合并
    return merge(left, right)

def merge(left, right):
    result = []
    i = j = 0

    while i < len(left) and j < len(right):
        if left[i] < right[j]:
            result.append(left[i])
            i += 1
        else:
            result.append(right[j])
            j += 1

    result.extend(left[i:])
    result.extend(right[j:])
    return result