33. 搜索旋转排序数组
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。
示例 1:
输入: nums = [4,5,6,7,0,1,2], target = 0
输出: 4
示例 2:
输入: nums = [4,5,6,7,0,1,2], target = 3
输出: -1
代码
class Solution(object):
def search(self
, nums
, target
):
"""
:type nums: List[int]
:type target: int
:rtype: int
"""
low
= 0
high
= len(nums
)-1
while low
<= high
:
mid
= low
+ (high
-low
)/2
if nums
[mid
] == target
:
return mid
if nums
[low
] <= nums
[mid
]:
if nums
[low
] <= target
and nums
[mid
] > target
:
high
= mid
-1
else:
low
= mid
+1
else:
if nums
[mid
] < target
and nums
[high
] >= target
:
low
= mid
+ 1
else:
high
= mid
-1
return -1
