Leetcode-33-Search in Rotated Sorted Array (Hard)
二分查找算法以及旋转之后的数组二分查找算法:
#!/usr/local/bin/python3
# -*- coding: utf-8 -*-
__author__ = 'author' class Solution(object):
def search(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: int
"""
return self.sorted_binary_search(nums, 0, len(nums) - 1, target) #二分查找算法
def binary_search(self, nums, start, end, targrt):
if start > end:
return -1
mid = start + (end - start)//2
if nums[mid] > targrt:
return self.binary_search(nums, start, mid - 1, targrt)
elif nums[mid] < targrt:
return self.binary_search(nums, mid + 1, end, targrt)
else:
return mid #旋转数组的折半查找算法
'''
要解决这道题,需要明确rotated sorted array的特性,
那么就是至少有一侧是排好序的(无论pivot在哪,自己画看看)。
接下来就只需要按照这个特性继续写下去就好。 如果target比A[mid]值要小
如果A[mid]右边有序(A[mid]<A[high])
那么target肯定不在右边(target比右边的都得小),在左边找
如果A[mid]左边有序
那么比较target和A[low],如果target比A[low]还要小,
证明target不在这一区,去右边找;反之,左边找。 如果target比A[mid]值要大
如果A[mid]左边有序(A[mid]>A[low])
那么target肯定不在左边(target比左边的都得大),在右边找
如果A[mid]右边有序
那么比较target和A[high],如果target比A[high]还要大,
证明target不在这一区,去左边找;反之,右边找。
'''
def sorted_binary_search(self, nums, start, end, targrt):
if start > end:
return -1
mid = start + (end - start)//2
if targrt == nums[mid]:
return mid
if nums[start] <= nums[mid]:
#如果左侧有序
if nums[start] <= targrt and targrt <= nums[mid]:
#如果target在左侧中
return self.sorted_binary_search(nums, start, mid - 1, targrt)
else:
return self.sorted_binary_search(nums, mid + 1, end, targrt)
else:
#如果右侧有序
if nums[mid] <= targrt and targrt <= nums[end]:
#如果target在右侧中
return self.sorted_binary_search(nums, mid + 1, end, targrt)
else:
return self.sorted_binary_search(nums, start, mid - 1, targrt) if __name__ == '__main__':
s = Solution()
print(s.binary_search([1,2,3,4,5,6,7,8,9], 0, 8, 9))
代码中注释参考了:http://www.cnblogs.com/springfor/p/3858140.html , 该博客中的算法描述比较易懂
Leetcode-33-Search in Rotated Sorted Array (Hard)的更多相关文章
- [array] leetcode - 33. Search in Rotated Sorted Array - Medium
leetcode - 33. Search in Rotated Sorted Array - Medium descrition Suppose an array sorted in ascendi ...
- LeetCode 33 Search in Rotated Sorted Array [binary search] <c++>
LeetCode 33 Search in Rotated Sorted Array [binary search] <c++> 给出排序好的一维无重复元素的数组,随机取一个位置断开,把前 ...
- [LeetCode] 33. Search in Rotated Sorted Array 在旋转有序数组中搜索
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e. ...
- LeetCode 33. Search in Rotated Sorted Array(在旋转有序序列中搜索)
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e. ...
- leetCode 33.Search in Rotated Sorted Array(排序旋转数组的查找) 解题思路和方法
Search in Rotated Sorted Array Suppose a sorted array is rotated at some pivot unknown to you before ...
- LeetCode 33.Search in Rotated Sorted Array(M)
题目: Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. ( ...
- leetcode 33. Search in Rotated Sorted Array
Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 migh ...
- Java [leetcode 33]Search in Rotated Sorted Array
题目描述: Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 ...
- [leetcode]33. Search in Rotated Sorted Array旋转过有序数组里找目标值
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e. ...
- LeetCode 33 Search in Rotated Sorted Array(循环有序数组中进行查找操作)
题目链接 :https://leetcode.com/problems/search-in-rotated-sorted-array/?tab=Description Problem :当前的数组 ...
随机推荐
- sqlclr创建表值函数案例
----------------------------------------------:定义表值类型:(1.一定返回的是IEnumerable2.一定带参数3.一定有FillRowMethodN ...
- 代码阅读软件kscope源码安装指导
安装 kscope-1.6.2 1. ./configure --without-arts --prefix=/soft/kscope-1.6.2 (I customize the installi ...
- Lex Yacc手册
Python Lex Yacc手册 本文是PLY (Python Lex-Yacc)的中文翻译版.转载请注明出处.这里有更好的阅读体验. 如果你从事编译器或解析器的开发工作,你可能对lex和yacc不 ...
- iOS基础 - 多媒体
一.播放视频 iOS提供了叫做MPMoviePlayerController.MPMoviePlayerViewController的两个类,可以用来轻松播放视频 YouTobe就是用MPMovieP ...
- c# in deep 之委托
通俗来讲,委托就是吩咐别人去做某件事,但不知道他具体会怎么做.使用委托必须注意的一个问题是内存泄露问题:假如委托实例本身不能被回收,委托实例会阻止他的目标被作为垃圾回收.尤其是假如某“短命”的对象调用 ...
- 最短路模板[spfa][dijkstra+堆优化][floyd]
借bzoj1624练了一下模板(虽然正解只是floyd) spfa: #include <cstdio> #include <cstring> #include <alg ...
- golang 之 bson 与 struct 转换
bson的介绍不说了golang下的解析包找到2个 一个是mongo的http://labix.org/gobson,另外一个比较小众https://github.com/sbunce/bson这里用 ...
- office文件的预览
使用FlexPaper实现office文件的预览(C#版) 需求很简单,用户上传office文件(word.excel.ppt)后,可以预览上传的这些文件.搜索的相关的资料后.整理如下: Step1. ...
- IOS学习之路十七(通过delegate进行页面传值)
加入有A B两个页面,要实现从A跳到B的时候把值传过去,现在用delegate协议来实现 在A中定义一个协议,定义一个实现该协议的属性变量 在B中定义一个值(要获得的值类型)和set方法. 要传值B ...
- SSH整合之_架构的历史序列图
只用jsp最原始的架构 jsp+DB的2层架构 jsp+DB+_Entity的2层架构 jsp+DB+_Entity3_+Service的三层架构 jsp+DB+_Entity3_+Service_H ...