Fix: Return first index for binary search with duplicate elements (#1…

searches/binary_search.py

@@ -198,20 +198,12 @@ def binary_search(sorted_collection: list[int], item: int) -> int:
     >>> binary_search([0, 5, 7, 10, 15], 6)
     -1
     """
-    if list(sorted_collection) != sorted(sorted_collection):
-        raise ValueError("sorted_collection must be sorted in ascending order")
-    left = 0
-    right = len(sorted_collection) - 1
-
-    while left <= right:
-        midpoint = left + (right - left) // 2
-        current_item = sorted_collection[midpoint]
-        if current_item == item:
-            return midpoint
-        elif item < current_item:
-            right = midpoint - 1
-        else:
-            left = midpoint + 1
+    # Use bisect_left to find the leftmost position
+    index = bisect_left(sorted_collection, item)
+
+    # Check if the item exists at that position
+    if index != len(sorted_collection) and sorted_collection[index] == item:
+        return index
     return -1