fix: improve code quality in searches and sorts

- binary_search.py: fix return type check in exponential_search (is None -> == -1)
- linear_search.py: use ValueError instead of generic Exception
- merge_sort.py: avoid O(n) pop(0) operations by using index-based merging

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

searches/binary_search.py

@@ -391,7 +391,7 @@ def exponential_search(sorted_collection: list[int], item: int) -> int:
     last_result = binary_search_by_recursion(
         sorted_collection=sorted_collection, item=item, left=left, right=right
     )
-    if last_result is None:
+    if last_result == -1:
         return -1
     return last_result
 

searches/linear_search.py

@@ -55,7 +55,7 @@ def rec_linear_search(sequence: list, low: int, high: int, target: int) -> int:
     -1
     """
     if not (0 <= high < len(sequence) and 0 <= low < len(sequence)):
-        raise Exception("Invalid upper or lower bound!")
+        raise ValueError("Invalid upper or lower bound!")
     if high < low:
         return -1
     if sequence[low] == target:

sorts/merge_sort.py

@@ -38,10 +38,17 @@ def merge(left: list, right: list) -> list:
         :return: Merged result
         """
         result = []
-        while left and right:
-            result.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
-        result.extend(left)
-        result.extend(right)
+        left_idx = 0
+        right_idx = 0
+        while left_idx < len(left) and right_idx < len(right):
+            if left[left_idx] <= right[right_idx]:
+                result.append(left[left_idx])
+                left_idx += 1
+            else:
+                result.append(right[right_idx])
+                right_idx += 1
+        result.extend(left[left_idx:])
+        result.extend(right[right_idx:])
         return result
 
     if len(collection) <= 1: