From e8f5ddd33e44dae4e0121f87a7bf92d754807e49 Mon Sep 17 00:00:00 2001
From: Dennis Sweeney <36520290+sweeneyde@users.noreply.github.com>
Date: Sun, 28 Feb 2021 16:32:04 -0500
Subject: [PATCH] Add whatsnew note for GH-22904 (#24672)

---
 Doc/whatsnew/3.10.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index 310554eabe6..12db4630081 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -615,6 +615,11 @@ Optimizations
   bytecode level.  It is now around 100% faster to create a function with parameter
   annotations.  (Contributed by Yurii Karabas and Inada Naoki in :issue:`42202`)
 
+* Substring search functions such as ``str1 in str2`` and ``str2.find(str1)``
+  now sometimes use Crochemore & Perrin's "Two-Way" string searching
+  algorithm to avoid quadratic behavior on long strings.  (Contributed
+  by Dennis Sweeney in :issue:`41972`)
+
 Deprecated
 ==========