From 07c44c1843fa695874e97a66692b134c3feeba5b Mon Sep 17 00:00:00 2001
From: Pravar Anu <63355747+PravarAnu@users.noreply.github.com>
Date: Thu, 6 Oct 2022 23:01:13 +0530
Subject: [PATCH] chore(CPlusPlus) : add reverse linked list  (#942)

---
 .../reverse-the-list-using-stack.cpp          | 97 +++++++++++++++++++
 algorithms/CPlusPlus/README.md                |  2 +-
 .../recursion/recursive-sum-of-n-numbers.py   |  0
 3 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 algorithms/CPlusPlus/Linked-Lists/reverse-the-list-using-stack.cpp
 rename recursive-sum-of-n-numbers.py => algorithms/Python/recursion/recursive-sum-of-n-numbers.py (100%)

diff --git a/algorithms/CPlusPlus/Linked-Lists/reverse-the-list-using-stack.cpp b/algorithms/CPlusPlus/Linked-Lists/reverse-the-list-using-stack.cpp
new file mode 100644
index 00000000..33121e63
--- /dev/null
+++ b/algorithms/CPlusPlus/Linked-Lists/reverse-the-list-using-stack.cpp
@@ -0,0 +1,97 @@
+/* 
+Algorithm: 
+    (i) Traverse the list and push all of its nodes onto a stack.
+    (ii) Traverse the list from the head node again and pop a value 
+        from the stack top and connect them in reverse order.
+    
+    
+TIME COMPLEXITY: O(n), as we are traversing over the linked list of size N using a while loop.
+SPACE COMPLEXITY: o(n), as we are using stack of size N in worst case which is extra space.
+
+ */
+
+
+#include <iostream>
+#include <stack>
+
+using namespace std;
+
+class Node {
+public:
+    int data;
+    Node *next;
+};
+Node *head;
+
+void Print(Node* n);
+void RevList();
+
+int main() {
+    head = NULL;
+
+    Node *first = new Node;
+    Node *second = new Node;
+    Node *third = new Node;
+    Node *fourth = new Node;
+    Node *fifth = new Node;
+    Node *sixth = new Node;
+    Node *seventh = new Node;
+
+    head = first;
+
+    first->data = 10;
+    first->next = second;
+    
+    second->data = 20;
+    second->next = third;
+    
+    third->data = 30;
+    third->next = fourth;
+    
+    fourth->data = 40;
+    fourth->next = fifth;
+
+    fifth->data = 50;
+    fifth->next = sixth;
+
+    sixth->data = 60;
+    sixth->next = seventh;
+
+    seventh->data = 70;
+    seventh->next = NULL;
+
+    Print(head);
+
+    RevList();
+    cout<<endl;
+    Print(head);
+
+    return 0;
+}
+
+void Print(Node* n){
+    if(n==NULL){
+        return;
+    }
+    cout<<n->data<<" ";
+    Print(n->next);
+}
+void RevList() {
+    if(head == NULL) return;
+    stack<Node *> st;
+    Node * temp = head;
+    while(temp!= NULL){
+        st.push(temp);
+        temp = temp->next;
+    }
+    temp = st.top();
+    head = temp;
+    st.pop();
+    
+    while(!st.empty()) {
+        temp->next = st.top();
+        temp = temp->next;
+        st.pop();
+    }
+    temp->next = NULL;
+}
diff --git a/algorithms/CPlusPlus/README.md b/algorithms/CPlusPlus/README.md
index b9b71156..66505d55 100644
--- a/algorithms/CPlusPlus/README.md
+++ b/algorithms/CPlusPlus/README.md
@@ -78,7 +78,7 @@
 - [Find Merge Point of two singly linked list](Linked-Lists/Find-Merge-Point.cpp)
 - [Segregate Even Odd Nodes of linked list](Linked-Lists/segregate-even-odd-nodes-of-linked-list.cpp)
 - [Remove Duplicate in Sorted linked list](Linked-Lists/remove-duplicates-in-sorted-linked-list.cpp)
-
+- [Reverse the linked list using stack](Linked-Lists/reverse-the-list-using-stack.cpp)
 ## Searching
 
 - [Linear Search](Searching/linear-search.cpp)
diff --git a/recursive-sum-of-n-numbers.py b/algorithms/Python/recursion/recursive-sum-of-n-numbers.py
similarity index 100%
rename from recursive-sum-of-n-numbers.py
rename to algorithms/Python/recursion/recursive-sum-of-n-numbers.py