[33. Search in Rotated Sorted Array] #leetcode

33_1017.py

class Solution(object):
    def search(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        # corner case: input is None or empty list
        if not nums:
            return -1
        
        # binary search
        left = 0
        right = len(nums) - 1
        while left <= right:
            mid = left + (right - left) // 2
            
            if nums[mid] == target:
                return mid
            
            # sorted from left to mid
            if nums[left] <= nums[mid]:
                 # target in left and mid
                 if target < nums[mid] and target >= nums[left]:
                    right = mid - 1
                 else:
                    left = mid + 1
            
            # sorted from mid to right 
            if nums[mid] <= nums[right]:
                if target > nums[mid] and target <= nums[right]:
                    left = mid + 1
                else:
                    right = mid - 1
    
        return -1