solve: searchInRotatedSortedArray

Author: GaggleHelena

search-in-rotated-sorted-array/yolophg.py

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+# Time Complexity: O(log n) - using a modified binary search, 
+# Space Complexity: O(1) - no extra space used, just a few variables.
+
+class Solution:
+    def search(self, nums: List[int], target: int) -> int:
+        # default result, in case the target isn't found
+        res = -1  
+         # set up the binary search range
+        left, right = 0, len(nums) - 1 
+
+        while left <= right:
+            # calculate the middle index
+            mid = left + (right - left) // 2 
+            
+            # found the target, store the index
+            if nums[mid] == target:  
+                res = mid
+            
+            # check if the left half is sorted
+            if nums[left] <= nums[mid]:  
+                if nums[left] <= target < nums[mid]:  
+                    # target in the left half, move right pointer
+                    right = mid - 1  
+                else: 
+                    # otherwise, search in the right half
+                    left = mid + 1 
+            
+            # otherwise, the right half must be sorted
+            else:  
+                if nums[mid] < target <= nums[right]:  
+                    # target in the right half, move left pointer
+                    left = mid + 1 
+                else: 
+                    # otherwise, search in the left half
+                    right = mid - 1 
+
+        return res