From d848a9c02c2449087bd3b7a7ac83604528085e56 Mon Sep 17 00:00:00 2001
From: Rajshekar723 <82643732+Rajshekar723@users.noreply.github.com>
Date: Tue, 4 Oct 2022 19:41:14 +0530
Subject: [PATCH 1/2] Add files via upload

knapsack problem using advanced recursion
---
 advance_recursion.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 advance_recursion.cpp

diff --git a/advance_recursion.cpp b/advance_recursion.cpp
new file mode 100644
index 0000000..632e5a1
--- /dev/null
+++ b/advance_recursion.cpp
@@ -0,0 +1,25 @@
+
+
+
+#include<iostream>
+using namespace std;
+
+int knapsack(int value[],int wt[],int n,int w)
+{
+    if(n==0 || w==0){
+        return 0;
+    }
+    if(wt[n-1]>w){
+        return knapsack(value,wt,n-1,w);
+    }
+    return max(knapsack(value,wt,n-1,w-wt[n-1])+value[n-1], knapsack(value,wt,n-1,w));
+}
+
+int main()
+{
+    int value[]={100,50,150};
+    int wt[]={10,20,30};
+    int w = 50;
+    cout<<knapsack(value,wt,3,w);
+    return 0;
+}
\ No newline at end of file

From 12f8b26a1c74d957ad6dbc5db4f71cbf5a0f6c6a Mon Sep 17 00:00:00 2001
From: Rajshekar723 <82643732+Rajshekar723@users.noreply.github.com>
Date: Tue, 4 Oct 2022 19:58:38 +0530
Subject: [PATCH 2/2] Add files via upload

finding the middle element of a stack pushed by the user
---
 find m in stack.cpp | 118 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 find m in stack.cpp

diff --git a/find m in stack.cpp b/find m in stack.cpp
new file mode 100644
index 0000000..af1f6d0
--- /dev/null
+++ b/find m in stack.cpp	
@@ -0,0 +1,118 @@
+
+/* C++ Program to implement a stack
+that supports findMiddle() and
+deleteMiddle in O(1) time */
+#include <bits/stdc++.h>
+using namespace std;
+ 
+class myStack {
+    struct Node {
+        int num;
+        Node* next;
+        Node* prev;
+ 
+        Node(int num) { this->num = num; }
+    };
+ 
+    // Members of stack
+    Node* head = NULL;
+    Node* mid = NULL;
+    int size = 0;
+ 
+public:
+    void push(int data)
+    {
+        Node* temp = new Node(data);
+        if (size == 0) {
+            head = temp;
+            mid = temp;
+            size++;
+            return;
+        }
+ 
+        head->next = temp;
+        temp->prev = head;
+ 
+        // update the pointers
+        head = head->next;
+        if (size % 2 == 1) {
+            mid = mid->next;
+        }
+        size++;
+    }
+ 
+    int pop()
+    {
+      int data=-1;
+        if (size != 0) {
+          data=head->num;
+            if (size == 1) {
+                head = NULL;
+                mid = NULL;
+            }
+            else {
+                head = head->prev;
+                head->next = NULL;
+                if (size % 2 == 0) {
+                    mid = mid->prev;
+                }
+            }
+            size--;
+        }
+      return data;
+    }
+ 
+    int findMiddle()
+    {
+        if (size == 0) {
+            return -1;
+        }
+        return mid->num;
+    }
+ 
+    void deleteMiddle()
+    {
+        if (size != 0) {
+            if (size == 1) {
+                head = NULL;
+                mid = NULL;
+            }
+            else if (size == 2) {
+                head = head->prev;
+                mid = mid->prev;
+                head->next = NULL;
+            }
+            else {
+                mid->next->prev = mid->prev;
+                mid->prev->next = mid->next;
+                if (size % 2 == 0) {
+                    mid = mid->prev;
+                }
+                else {
+                    mid = mid->next;
+                }
+            }
+            size--;
+        }
+    }
+};
+ 
+int main()
+{
+    myStack st;
+    st.push(11);
+    st.push(22);
+    st.push(33);
+    st.push(44);
+    st.push(55);
+    st.push(66);
+    st.push(77);
+    st.push(88);
+    st.push(99);
+    cout <<"Popped : "<< st.pop() << endl;
+    cout <<"Popped : "<< st.pop() << endl;
+    cout <<"Middle Element : "<< st.findMiddle() << endl;
+    st.deleteMiddle();
+    cout <<"New Middle Element : "<< st.findMiddle() << endl;
+    return 0;
+}