From 36d5eb111a4ffcebcdf9d95e56c09df056914f64 Mon Sep 17 00:00:00 2001
From: Aryadev Chavali <aryadev@aryadevchavali.com>
Date: Sun, 21 Nov 2021 00:28:23 +0000
Subject: (list)+recursive reverse algorithm for singly linked lists

Pretty simple, returns the last node as that's the new root node.
Uses default parameters to make sure the first node has next set to null.
---
 list.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/list.cpp b/list.cpp
index 593a87e..5dc6d18 100644
--- a/list.cpp
+++ b/list.cpp
@@ -42,6 +42,18 @@ List<T> *append(List<T> *lst, T value)
   return lst;
 }
 
+/** Reverse a list
+ */
+template <typename T>
+List<T> *reverse(List<T> *lst, List<T> *prev = NULL)
+{
+  auto next = lst->next;
+  lst->next = prev;
+  if (next == NULL)
+    return lst;
+  return reverse(next, lst);
+}
+
 template <typename T>
 std::ostream& operator<<(std::ostream& ostream, const List<T> *lst)
 {
@@ -57,5 +69,8 @@ int main(void)
   for (int i = 2; i < 10; ++i)
     lst = append(lst, i);
   std::cout << lst << std::endl;
+  lst = reverse(lst);
+  std::cout << lst << std::endl;
+  delete lst;
   return 0;
 }
-- 
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