From f126613abd6a1781c1a1467ce231bc51b38aebc2 Mon Sep 17 00:00:00 2001
From: Saadanjum0 <160885369+Saadanjum0@users.noreply.github.com>
Date: Fri, 2 Oct 2026 13:58:17 +0500
Subject: [PATCH] Fix quick_select crashing on non-positive rank in
 median_of_medians.py

quick_select only rejected target > len(arr), so a rank of 0 or
negative fell through to median_of_medians() on a progressively
smaller list until it indexed an empty list, raising IndexError
instead of returning -1 like other invalid input.

Added doctests covering target = 0 and target = -1.
---
 searches/median_of_medians.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/searches/median_of_medians.py b/searches/median_of_medians.py
index a8011a34af76..dd46613c2bff 100644
--- a/searches/median_of_medians.py
+++ b/searches/median_of_medians.py
@@ -74,10 +74,14 @@ def quick_select(arr: list, target: int) -> int:
     3
     >>> quick_select([3, 5, 7, 10, 2, 12], 3)
     5
+    >>> quick_select([2, 4, 5, 7, 899, 54, 32], 0)
+    -1
+    >>> quick_select([2, 4, 5, 7, 899, 54, 32], -1)
+    -1
     """
 
     # Invalid Input
-    if target > len(arr):
+    if target <= 0 or target > len(arr):
         return -1
 
     # x is the estimated pivot by median of medians algorithm