LeetCode
LeetCode 33 Search In Rotated Sorted Array - Medium
33. Search in Rotated Sorted Array
33. Search In Rotated Sorted Array — Medium
Problem
- Search in Rotated Sorted Array
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).
Example 1:
Input: nums = [4,5,6,7,0,1,2], target = 0 Output: 4 Example 2:
Input: nums = [4,5,6,7,0,1,2], target = 3 Output: -1
Solution
### One Pass Binary Search Solution:
class Solution:
def search(self, A, target):
if not A:
return -1
start, end = 0, len(A) - 1
while start + 1 < end:
mid = (start + end) // 2
if A[mid] >= A[start]:
if A[start] <= target <= A[mid]:
end = mid
else:
start = mid
else:
if A[mid] <= target <= A[end]:
start = mid
else:
end = mid
if A[start] == target:
return start
if A[end] == target:
return end
return -1