From a8d2f4161f2d52bcbbf0b542f37b6f6e319d2391 Mon Sep 17 00:00:00 2001
From: Lucas Ma <7184042+pony-maggie@users.noreply.github.com>
Date: Mon, 15 Jun 2026 08:05:42 +0800
Subject: [PATCH] fix: handle missing lower bound in exponential search

---
 searches/exponential_search.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/searches/exponential_search.py b/searches/exponential_search.py
index ed09b14e101c..d38137b60415 100644
--- a/searches/exponential_search.py
+++ b/searches/exponential_search.py
@@ -81,10 +81,19 @@ def exponential_search(sorted_collection: list[int], item: int) -> int:
     1
     >>> exponential_search([0, 5, 7, 10, 15], 6)
     -1
+    >>> exponential_search([], 1)
+    -1
+    >>> exponential_search([1, 1], -1)
+    -1
     """
     if list(sorted_collection) != sorted(sorted_collection):
         raise ValueError("sorted_collection must be sorted in ascending order")
 
+    if not sorted_collection:
+        return -1
+
+    if sorted_collection[0] > item:
+        return -1
     if sorted_collection[0] == item:
         return 0