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033 search in rotated sorted array

33. Search in Rotated Sorted Array

题目: https://leetcode.com/problems/search-in-rotated-sorted-array/

难度: Medium

思路:

下面是rotated-array图解,

rotated-array图解

所以直接用二分,O(lg(n)) - 如果是mid,return mid - 如果mid在绿色线上,就对绿色线进行二分 - 如果mid在红色线上,就对红色线进行二分 - 都没找到,return -1

class Solution(object):
    def search(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        l, r = 0, len(nums) - 1
        while l <= r:
            mid = l + ((r - l) >> 2)
            if nums[mid] == target:
                return mid
            if nums[mid] < nums[r]:
                if nums[mid] < target <= nums[r]:
                    l = mid + 1
                else:
                    r = mid - 1
            else:
                if nums[l] <= target < nums[mid]:
                    r = mid - 1
                else:
                    l = mid + 1
        return -1


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