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  • LeetCode(力扣)——Search in Rotated Sorted Array 搜索旋转排序数组 python实现

    题目描述:

    python实现 Search in Rotated Sorted Array 搜索旋转排序数组  

      中文:假设按照升序排序的数组在预先未知的某个点上进行了旋转。

      ( 例如,数组 [0,1,2,4,5,6,7] 可能变为 [4,5,6,7,0,1,2] )。

      搜索一个给定的目标值,如果数组中存在这个目标值,则返回它的索引,否则返回 -1 。

      你可以假设数组中不存在重复的元素。

      你的算法时间复杂度必须是 O(log n) 级别。

      英文:Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.

    (i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]).

    You are given a target value to search. If found in the array return its index, otherwise return -1.

    You may assume no duplicate exists in the array.

    Your algorithm's runtime complexity must be in the order of O(log n).

     1 class Solution(object):
     2     def search(self, nums, target):
     3         """
     4         :type nums: List[int]
     5         :type target: int
     6         :rtype: int
     7         """
     8         start = 0
     9         end = len(nums)-1
    10         while start<=end:
    11             mid = (start + end)/2   #对于整数会自动省去小数部分
    12             if nums[mid] == target:
    13                 return mid
    14             if nums[mid]>=nums[start]:
    15                 if target >= nums[start] and target<=nums[mid]:
    16                     end = mid-1
    17                 else:
    18                     start = mid + 1
    19                     
    20             if nums[mid]<nums[end]:
    21                 if target > nums[mid] and target<=nums[end]:
    22                     start = mid+1
    23                     
    24                 else:
    25                     end = mid -1
    26         return -1

    题目来源:力扣题库

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  • 原文地址:https://www.cnblogs.com/spp666/p/11536041.html
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