leetcode: 33. Search in Rotated Sorted Array

# Suppose a sorted array 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.

# Time:  O(logn)
# Space: O(1)
class Solution():
    def search(self, x, target):
        left, right = 0, len(x) - 1
        while left <= right:
            mid = (left + right) // 2
            if x[mid] == target:
                return mid
            elif (x[left] <= target < x[mid]) or (x[left] > x[mid] and not x[mid] < target <= x[right]):
                right = mid - 1
            else:
                left = mid + 1
        return -1


if __name__ == "__main__":
    assert Solution().search([3, 5, 1], 3) == 0
    assert Solution().search([1], 1) == 0
    assert Solution().search([4, 5, 6, 7, 0, 1, 2], 5) == 1