From 0b78c71d1cc7b1dcb8356256f13b141589f50bf8 Mon Sep 17 00:00:00 2001
From: Muhammad Sameer Farooq <me.sameer.farooq@gmail.com>
Date: Sat, 17 Oct 2020 21:10:34 +0500
Subject: [PATCH] Added AVL Tree implementation in C++

---
 trees/AVL Tree/CPP/AVL Tree.cpp | 191 ++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 trees/AVL Tree/CPP/AVL Tree.cpp

diff --git a/trees/AVL Tree/CPP/AVL Tree.cpp b/trees/AVL Tree/CPP/AVL Tree.cpp
new file mode 100644
index 00000000..3bd32d55
--- /dev/null
+++ b/trees/AVL Tree/CPP/AVL Tree.cpp	
@@ -0,0 +1,191 @@
+#include<iostream>
+#include<cstdio>
+#include<sstream>
+#include<algorithm>
+
+#define pow2(n) (1 << (n))
+
+using namespace std;
+
+
+class avl_tree 
+{
+   public:
+      int height(avl *);
+      int difference(avl *);
+      avl *rr_rotat(avl *);
+      avl *ll_rotat(avl *);
+      avl *lr_rotat(avl*);
+      avl *rl_rotat(avl *);
+      avl * balance(avl *);
+      avl * insert(avl*, int);
+      void show(avl*, int);
+      void inorder(avl *);
+      void preorder(avl *);
+      void postorder(avl*);
+      avl_tree() 
+	  {
+         rightNode = NULL;
+      }
+};
+int avl_tree::height(avl *t) {
+   int h = 0;
+   if (t != NULL) {
+      int l_height = height(t->leftNode);
+      int r_height = height(t->rightNode);
+      int max_height = max(l_height, r_height);
+      h = max_height + 1;
+   }
+   return h;
+}
+int avl_tree::difference(avl *t) {
+   int l_height = height(t->leftNode);
+   int r_height = height(t->rightNode);
+   int b_factor = l_height - r_height;
+   return b_factor;
+}
+avl *avl_tree::rr_rotat(avl *parent) {
+   avl *t;
+   t = parent->rightNode;
+   parent->rightNode = t->leftNode;
+   t->leftNode = parent;
+   cout<<"Right-Right Rotation";
+   return t;
+}
+avl *avl_tree::ll_rotat(avl *parent) {
+   avl *t;
+   t = parent->leftNode;
+   parent->leftNode = t->rightNode;
+   t->rightNode = parent;
+   cout<<"Left-Left Rotation";
+   return t;
+}
+avl *avl_tree::lr_rotat(avl *parent) {
+   avl *t;
+   t = parent->leftNode;
+   parent->leftNode = rr_rotat(t);
+   cout<<"Left-Right Rotation";
+   return ll_rotat(parent);
+}
+avl *avl_tree::rl_rotat(avl *parent) {
+   avl *t;
+   t = parent->rightNode;
+   parent->rightNode = ll_rotat(t);
+   cout<<"Right-Left Rotation";
+   return rr_rotat(parent);
+}
+avl *avl_tree::balance(avl *t) {
+   int bal_factor = difference(t);
+   if (bal_factor > 1) {
+      if (difference(t->leftNode) > 0)
+         t = ll_rotat(t);
+      else
+         t = lr_rotat(t);
+   } else if (bal_factor < -1) {
+      if (difference(t->rightNode) > 0)
+         t = rl_rotat(t);
+      else
+         t = rr_rotat(t);
+   }
+   return t;
+}
+avl *avl_tree::insert(avl *rightNode, int v) {
+   if (rightNode == NULL) {
+      rightNode = new avl;
+      rightNode->data = v;
+      rightNode->leftNode = NULL;
+      rightNode->rightNode = NULL;
+      return rightNode;
+   } else if (v< rightNode->data) {
+      rightNode->leftNode = insert(rightNode->leftNode, v);
+      rightNode = balance(rightNode);
+   } else if (v >= rightNode->data) {
+      rightNode->rightNode = insert(rightNode->rightNode, v);
+      rightNode = balance(rightNode);
+   } return rightNode;
+}
+void avl_tree::show(avl *p, int leftNode) {
+   int i;
+   if (p != NULL) {
+      show(p->rightNode, leftNode+ 1);
+      cout<<" ";
+      if (p == rightNode)
+         cout << "Root -> ";
+      for (i = 0; i < leftNode&& p != rightNode; i++)
+         cout << " ";
+         cout << p->data;
+         show(p->leftNode, leftNode + 1);
+   }
+}
+void avl_tree::inorder(avl *t) {
+   if (t == NULL)
+      return;
+      inorder(t->leftNode);
+      cout << t->data << " ";
+      inorder(t->rightNode);
+}
+void avl_tree::preorder(avl *t) {
+   if (t == NULL)
+      return;
+      cout << t->data << " ";
+      preorder(t->leftNode);
+      preorder(t->rightNode);
+}
+void avl_tree::postorder(avl *t) {
+   if (t == NULL)
+      return;
+      postorder(t ->leftNode);
+      postorder(t ->rightNode);
+      cout << t->data << " ";
+}
+int main() {
+   int c, i;
+   avl_tree avl;
+   while (1) {
+      cout << "1.Insert Element into the tree" << endl;
+      cout << "2.show Balanced AVL Tree" << endl;
+      cout << "3.InOrder traversal" << endl;
+      cout << "4.PreOrder traversal" << endl;
+      cout << "5.PostOrder traversal" << endl;
+      cout << "6.Exit" << endl;
+      cout << "Enter your Choice: ";
+      cin >> c;
+      switch (c) {
+         case 1:
+            cout << "Enter value to be inserted: ";
+            cin >> i;
+            rightNode = avl.insert(rightNode, i);
+         break;
+         case 2:
+            if (rightNode == NULL) {
+               cout << "Tree is Empty" << endl;
+               continue;
+            }
+            cout << "Balanced AVL Tree:" << endl;
+            avl.show(rightNode, 1);
+            cout<<endl;
+         break;
+         case 3:
+            cout << "Inorder Traversal:" << endl;
+            avl.inorder(rightNode);
+            cout << endl;
+         break;
+         case 4:
+            cout << "Preorder Traversal:" << endl;
+            avl.preorder(rightNode);
+            cout << endl;
+         break;
+         case 5:
+            cout << "Postorder Traversal:" << endl;
+            avl.postorder(rightNode);
+            cout << endl;
+         break;
+         case 6:
+            exit(1);
+         break;
+         default:
+            cout << "Wrong Choice" << endl;
+      }
+   }
+   return 0;
+}
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