From 8b710eff1c06c329f662835a809833391b6772bf Mon Sep 17 00:00:00 2001
From: POLKAM ARAVIND <2400030648@kluniversity.in>
Date: Mon, 24 Nov 2025 18:12:39 +0530
Subject: [PATCH 1/2] Fix: Return first index for binary search with duplicate
 elements (#13840)

Refactored binary_search function to use bisect_left for improved efficiency.
---
 searches/binary_search.py | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/searches/binary_search.py b/searches/binary_search.py
index 2e66b672d5b4..b309dbee50d5 100644
--- a/searches/binary_search.py
+++ b/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
 
 

From 46f2e3d560e43c5342ba33304380c162ae5d005e Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Mon, 24 Nov 2025 12:45:49 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 searches/binary_search.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/searches/binary_search.py b/searches/binary_search.py
index b309dbee50d5..e0ffd3e31216 100644
--- a/searches/binary_search.py
+++ b/searches/binary_search.py
@@ -200,7 +200,7 @@ def binary_search(sorted_collection: list[int], item: int) -> int:
     """
     # 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