Merge pull request #58 from tanay-nagde/main

implemented avl tree in c++ | please accept my pr for hacktoberfest2023

C++/AvlTree.cpp

@@ -0,0 +1,121 @@
+#include <iostream>
+using namespace std;
+
+class Node {
+public:
+    int key;
+    Node* left;
+    Node* right;
+    int height;
+    Node(int k) : key(k), left(nullptr), right(nullptr), height(1) {}
+};
+
+class AVLTree {
+private:
+    Node* root;
+
+    int getHeight(Node* node) {
+        if (node == nullptr)
+            return 0;
+        return node->height;
+    }
+
+    int getBalanceFactor(Node* node) {
+        if (node == nullptr)
+            return 0;
+        return getHeight(node->left) - getHeight(node->right);
+    }
+
+    void updateHeight(Node* node) {
+        if (node != nullptr)
+            node->height = 1 + max(getHeight(node->left), getHeight(node->right));
+    }
+
+    Node* rotateRight(Node* y) {
+        Node* x = y->left;
+        Node* T2 = x->right;
+        x->right = y;
+        y->left = T2;
+        updateHeight(y);
+        updateHeight(x);
+        return x;
+    }
+
+    Node* rotateLeft(Node* x) {
+        Node* y = x->right;
+        Node* T2 = y->left;
+        y->left = x;
+        x->right = T2;
+        updateHeight(x);
+        updateHeight(y);
+        return y;
+    }
+
+    Node* insert(Node* node, int key) {
+        if (node == nullptr)
+            return new Node(key);
+        if (key < node->key)
+            node->left = insert(node->left, key);
+        else if (key > node->key)
+            node->right = insert(node->right, key);
+        else
+            return node;
+
+        updateHeight(node);
+
+        int balance = getBalanceFactor(node);
+
+        // Left Heavy
+        if (balance > 1) {
+            if (key < node->left->key) // Left-Left case
+                return rotateRight(node);
+            if (key > node->left->key) { // Left-Right case
+                node->left = rotateLeft(node->left);
+                return rotateRight(node);
+            }
+        }
+        // Right Heavy
+        if (balance < -1) {
+            if (key > node->right->key) // Right-Right case
+                return rotateLeft(node);
+            if (key < node->right->key) { // Right-Left case
+                node->right = rotateRight(node->right);
+                return rotateLeft(node);
+            }
+        }
+
+        return node;
+    }
+
+public:
+    AVLTree() : root(nullptr) {}
+
+    void insert(int key) {
+        root = insert(root, key);
+    }
+
+    void display(Node* node, int indent = 0) {
+        if (node != nullptr) {
+            display(node->right, indent + 4);
+            cout << string(indent, ' ') << node->key << endl;
+            display(node->left, indent + 4);
+        }
+    }
+
+    void displayTree() {
+        display(root);
+    }
+};
+
+int main() {
+    AVLTree tree;
+    tree.insert(10);
+    tree.insert(20);
+    tree.insert(30);
+    tree.insert(40);
+    tree.insert(50);
+
+    tree.displayTree();
+
+    return 0;
+}