From c760166965dab71e12ef51ea8bdc5fa72b1d317c Mon Sep 17 00:00:00 2001
From: Alvin Philips <alvinphilips257@gmail.com>
Date: Tue, 19 Oct 2021 05:31:00 +0530
Subject: [PATCH] Create reverse_binary_tree.cpp

---
 .../reverse_binary_tree.cpp                   | 110 ++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 operations_on_datastructures/reverse_binary_tree.cpp

diff --git a/operations_on_datastructures/reverse_binary_tree.cpp b/operations_on_datastructures/reverse_binary_tree.cpp
new file mode 100644
index 000000000..f22acb371
--- /dev/null
+++ b/operations_on_datastructures/reverse_binary_tree.cpp
@@ -0,0 +1,110 @@
+/**
+ * @file
+ * @brief An implemention for Reversing a Binary Tree recursively.
+ *
+ */
+
+#include <cassert>   /// For assert
+#include <iostream>  /// For IO operations
+#include <queue>     /// For std::queue
+#include <vector>    /// For std::vector
+
+/**
+ * @namespace operations_on_datastructures
+ * @brief Operations on Data Structures
+ */
+namespace operations_on_datastructures {
+
+/**
+ * @namespace reverse_binary_tree
+ * @brief Functions for Creating and Reversing a Binary Tree
+ */
+namespace reverse_binary_tree {
+
+/**
+ * @brief A Node struct that represents a single node in a Binary Tree
+ */
+struct Node {
+    int data;     ///< The value of the Node
+    Node* left;   ///< The Node's left child
+    Node* right;  ///< The Node's right child
+    /**
+     * @brief Creates a new Node with some initial data
+     */
+    Node(int _data) {
+        data = _data;  ///< Set value of Node data
+        left = NULL;   ///< Initialize left child to NULL
+        right = NULL;  ///< Initialize right child to NULL
+    }
+};
+
+/**
+ * @brief A Binary Tree class that implements a Binary Search Tree
+ *(BST) by default.
+ */
+class BinaryTree {
+ private:
+    Node* root;  ///< Pointer to root node of Binary Tree
+    /**
+     * @brief inserts a node in the Binary Tree, with the behaviouur of
+     * a Binary Search Tree.
+     * @details Nodes with smaller values are inserted in the left
+     * subtree, and Nodes with larger values are inserted into the
+     * right subtree recursively. Time Complexity: O(log(n))
+     * @param data The data/value of the Node to be inserted
+     * @param pivot A pointer to the root node of the (sub)tree
+     * @returns Node pointer to the root
+     */
+    Node* insert(int data, Node* pivot) {
+        if (pivot == NULL) {
+            return new Node(data);
+        }
+        if (data <= pivot->data) {
+            pivot->left = insert(data, pivot->left);
+        } else {
+            pivot->right = insert(data, pivot->right);
+        }
+        return pivot;
+    }
+    Node* reverseBinaryTree(Node* pivot) {
+        if (pivot == NULL) {
+            return pivot;
+        }
+        Node* temp = pivot->left;
+        pivot->left = reverseBinaryTree(pivot->right);
+        pivot->right = reverseBinaryTree(temp);
+        return pivot;
+    }
+
+ public:
+    BinaryTree() { root = NULL; }
+    BinaryTree(Node* _root) { root = _root; }
+    BinaryTree(int data) { root = new Node(data); }
+    void add(int data) { root = insert(data, root); }
+    void reverse() { root = reverseBinaryTree(root); }
+    std::vector<int> get_level_order() {
+        std::vector<int> data;
+        if (root == NULL) {
+            return data;
+        }
+        std::queue<Node*> nodes;
+        nodes.push(root);
+        while (!nodes.empty()) {
+            Node* temp = nodes.back();
+            data.push_back(temp);
+            nodes.pop();
+            if (temp->left != NULL) {
+                nodes.push(temp->left);
+            }
+            if (temp->right != NULL) {
+                nodes.push(temp->right);
+            }
+        }
+        return data;
+    }
+};
+
+}  // namespace reverse_binary_tree
+}  // namespace operations_on_datastructures
+
+int main() {}
\ No newline at end of file