Fetch the repository succeeded.
This action will force synchronization from 陌溪/LearningNotes, which will overwrite any changes that you have made since you forked the repository, and can not be recovered!!!
Synchronous operation will process in the background and will refresh the page when finishing processing. Please be patient.
归并排序是用到了分治的思想,分治的思想是将一个大问题拆分成很多歌小问题,然后再将已经处理完成的小问题合并成整个大问题,在这个过程中。在这个过程中,大问题就得到了解决,在Hadoop中MapReduce就是利用了这个思想。
代码分为两部分,一个是分治,一个合并
# 归并排序
class Solution:
def MergeSort(self, arrayList):
arrayLen = len(arrayList)
# 判断输入参数的正确性
if arrayLen < 1:
return []
# 归并的出口是当分解到长度为1的时候
if arrayLen == 1:
return arrayList
# 获取中间索引值
middleIndex = arrayLen >> 1
# 递归左边部分
sortedLeft = self.MergeSort(arrayList[:middleIndex])
# 递归右边部分
sortedRight = self.MergeSort(arrayList[middleIndex:])
# 合并代码
return self.MergeCore(sortedLeft, sortedRight)
def MergeCore(self, leftList, rightList):
# leftIndex = 0
# rightIndex = 0
# # 由于多次用,length 我们自己保存
# leftLen = len(leftList)
# rightLen = len(rightList)
retList = []
while leftList != [] and rightList != []:
leftValue = leftList[0]
rightValue = rightList[0]
if leftValue >= rightValue:
retList.append(rightValue)
del rightList[0]
else:
retList.append(leftValue)
del leftList[0]
# 归并排序后,然后
if leftList != []:
for i in leftList:
retList.append(i)
if rightList != []:
for i in rightList:
retList.append(i)
return retList
if __name__ == '__main__':
print(Solution().MergeSort([1,8,7,5,4,2]))
此处可能存在不合适展示的内容,页面不予展示。您可通过相关编辑功能自查并修改。
如您确认内容无涉及 不当用语 / 纯广告导流 / 暴力 / 低俗色情 / 侵权 / 盗版 / 虚假 / 无价值内容或违法国家有关法律法规的内容,可点击提交进行申诉,我们将尽快为您处理。