fix: return the correct index when duplicates in binary_search

Author: Andres Torres

searches/binary_search.py

@@ -202,17 +202,19 @@ def binary_search(sorted_collection: list[int], item: int) -> int:
         raise ValueError("sorted_collection must be sorted in ascending order")
     left = 0
     right = len(sorted_collection) - 1
+    result = -1
 
     while left <= right:
         midpoint = left + (right - left) // 2
         current_item = sorted_collection[midpoint]
         if current_item == item:
-            return midpoint
+            result = midpoint
+            right = midpoint - 1
         elif item < current_item:
             right = midpoint - 1
         else:
             left = midpoint + 1
-    return -1
+    return result
 
 
 def binary_search_std_lib(sorted_collection: list[int], item: int) -> int: