33.搜索旋转排序数组.py

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# @lc app=leetcode.cn id=33 lang=python3
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# [33] 搜索旋转排序数组
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# https://leetcode-cn.com/problems/search-in-rotated-sorted-array/description/
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# algorithms
# Medium (35.95%)
# Total Accepted:    17.7K
# Total Submissions: 49.2K
# Testcase Example:  '[4,5,6,7,0,1,2]\n0'
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# 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。
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# ( 例如，数组 [0,1,2,4,5,6,7] 可能变为 [4,5,6,7,0,1,2] )。
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# 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 。
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# 你可以假设数组中不存在重复的元素。
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# 你的算法时间复杂度必须是 O(log n) 级别。
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# 示例 1:
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# 输入: nums = [4,5,6,7,0,1,2], target = 0
# 输出: 4
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# 示例 2:
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# 输入: nums = [4,5,6,7,0,1,2], target = 3
# 输出: -1
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class Solution:
    def search(self, nums: List[int], target: int) -> int:
        last_index_nums=len(nums)-1
        first_indeex_nums=0  
        mid_index=int((last_index_nums+first_indeex_nums)/2)
        while True:
            if nums[mid_index]>=nums[mid_index-1]:
                first_indeex_nums=mid_index
                mid_index=int((last_index_nums+first_indeex_nums)/2)
            else:
                last_index_nums=mid_index
                mid_index=int((last_index_nums+first_indeex_nums)/2)