code.cpp

/* **************************************************************************
 * Copyright 2024 The OpenGenus.org Authors. All Rights Reserved.
 *
 * Code for the book "DAILY 43: Algorithmic Problems for Coding Interviews: Easy level, C++ edition"
 *
 * Licensed under the GNU General Public License, Version 3.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.gnu.org/licenses/gpl-3.0.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For details about the book, please visit: https://www.amazon.com/dp/B0CZJNBLQS
 * *************************************************************************/

#include <iostream>

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int val) : val(val), left(nullptr), right(nullptr) {}
};

TreeNode* invertTree(TreeNode* root) {
    if (root) {
        TreeNode* temp = root->left;
        root->left = root->right;
        root->right = temp;
        invertTree(root->left);
        invertTree(root->right);
    }
    return root;
}

// Utility function to print the tree in inorder traversal
void printInorder(TreeNode* root) {
    if (root) {
        printInorder(root->left);
        std::cout << root->val << " ";
        printInorder(root->right);
    }
}

int main() {
    // Create a binary tree
    TreeNode* root = new TreeNode(4);
    root->left = new TreeNode(2);
    root->right = new TreeNode(7);
    root->left->left = new TreeNode(1);
    root->left->right = new TreeNode(3);
    root->right->left = new TreeNode(6);
    root->right->right = new TreeNode(9);

    std::cout << "Original Tree (inorder): ";
    printInorder(root);
    std::cout << std::endl;

    // Invert the tree
    TreeNode* invertedTree = invertTree(root);

    std::cout << "Inverted Tree (inorder): ";
    printInorder(invertedTree);
    std::cout << std::endl;

    return 0;
}