Added search in a rotated sorted array in searches

Author: Tarannum9623

searches/search_in_a_rotated_sorted_array.py

@@ -0,0 +1,78 @@
+def search_in_rotated_sorted_array(nums: list[int], target: int) -> int:
+    """
+    Search for a target value in a rotated sorted array.
+
+    This function implements a modified binary search to find the index of a target
+    value in an array that was originally sorted in ascending order but then rotated
+    at some pivot point unknown to you beforehand.
+
+    Args:
+        nums: A list of integers that is sorted in ascending order and then rotated
+              at some pivot point. Example: [4, 5, 6, 7, 0, 1, 2]
+        target: The integer value to search for in the array.
+
+    Returns:
+        int: The index of target in nums if found, otherwise -1.
+
+    Raises:
+        ValueError: If nums is empty.
+
+    Examples:
+        >>> search_in_rotated_sorted_array([4, 5, 6, 7, 0, 1, 2], 0)
+        4
+        >>> search_in_rotated_sorted_array([4, 5, 6, 7, 0, 1, 2], 3)
+        -1
+        >>> search_in_rotated_sorted_array([1], 0)
+        -1
+        >>> search_in_rotated_sorted_array([1], 1)
+        0
+        >>> search_in_rotated_sorted_array([], 1)
+        Traceback (most recent call last):
+            ...
+        ValueError: nums cannot be empty
+    """
+    if not nums:
+        raise ValueError("nums cannot be empty")
+
+    left_index, right_index = 0, len(nums) - 1
+
+    while left_index <= right_index:
+        middle_index = (left_index + right_index) // 2
+
+        if nums[middle_index] == target:
+            return middle_index
+
+        # Check if left half is sorted
+        if nums[left_index] <= nums[middle_index]:
+            # Target is in the sorted left half
+            if nums[left_index] <= target < nums[middle_index]:
+                right_index = middle_index - 1
+            else:
+                left_index = middle_index + 1
+        # Right half is sorted
+        elif nums[middle_index] < target <= nums[right_index]:
+            left_index = middle_index + 1
+        else:
+            right_index = middle_index - 1
+
+    return -1
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
+
+    # Additional test cases
+    test_cases = [
+        ([4, 5, 6, 7, 0, 1, 2], 0),
+        ([4, 5, 6, 7, 0, 1, 2], 3),
+        ([1], 0),
+        ([1], 1),
+        ([3, 1], 1),
+        ([3, 1], 3),
+    ]
+
+    for nums, target in test_cases:
+        result = search_in_rotated_sorted_array(nums, target)
+        print(f"search_in_rotated_sorted_array({nums}, {target}) = {result}")