归并排序python实现代码，归并排序python,def mergesor

归并排序python实现代码，归并排序python,def mergesor

def mergesort(arr):      if len(arr) == 1:          return arr      m = len(arr) / 2      l = mergesort(arr[:m])      r = mergesort(arr[m:])      if not len(l) or not len(r):          return l or r      result = []      i = j = 0      while (len(result) < len(r)+len(l)):                  if l[i] < r[j]:              result.append(l[i])              i += 1          else:              result.append(r[j])              j += 1                      if i == len(l) or j == len(r):                          result.extend(l[i:] or r[j:])              break      return result