{"id":8792,"date":"2025-07-31T19:40:18","date_gmt":"2025-07-31T14:10:18","guid":{"rendered":"https:\/\/namastedev.com\/blog\/?p=8792"},"modified":"2025-07-31T22:34:44","modified_gmt":"2025-07-31T17:04:44","slug":"invert-a-binary-tree","status":"publish","type":"post","link":"https:\/\/namastedev.com\/blog\/invert-a-binary-tree\/","title":{"rendered":"Invert a Binary Tree"},"content":{"rendered":"\n<!--Symmtery: Iterative Approach -->\n<link\n    href=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/themes\/prism-tomorrow.min.css\"\n    rel=\"stylesheet\"\n\/>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/prism.min.js\"><\/script>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/prismjs@1.29.0\/plugins\/autoloader\/prism-autoloader.min.js\"><\/script>\n\n<style> \n.wp_blog_theme {\n  --primary: #E58C32;\n  --secondary: #f8c291;\n  --light-bg: #fef9f4;\n  --text-dark: #2d2d2d;\n  --tab-radius: 12px;\n  --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);\n  --code-bg: #001f3f;\n  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4px;\n  font-family: 'Courier New', monospace;\n}\n.wp_blog_explanation img {\n  max-width: 100%;\n  border-radius: var(--tab-radius);\n  margin-top: 1rem;\n  box-shadow: 0 2px 12px rgba(0,0,0,0.06);\n}\n\n\/* Tab Buttons *\/\n.wp_blog_code-tabs-header {\n  display: flex;\n  flex-wrap: wrap;\n  gap: 0.5rem;\n  margin-bottom: 1rem;\n}\n.wp_blog_code-tab-button {\n  padding: 0.6rem 1.2rem;\n  border: 1px solid var(--primary);\n  background: white;\n  color: var(--primary);\n  border-radius: 50px;\n  font-weight: 600;\n  cursor: pointer;\n  transition: all 0.3s ease;\n}\n.wp_blog_code-tab-button:hover {\n  background: var(--secondary);\n}\n.wp_blog_code-tab-button.active {\n  background: var(--primary);\n  color: white;\n}\n\n\/* Code Content *\/\n.wp_blog_code-tab-content {\n  display: none;\n  background: var(--code-bg);\n  border-radius: var(--tab-radius);\n}\n.wp_blog_code-tab-content.active {\n  display: block;\n}\n.wp_blog_code-tab-content pre {\n  margin: 0;\n  padding: 1.5rem;\n  font-size: 1rem;\n  overflow-x: auto;\n  background: var(--code-bg);\n  border-radius: var(--tab-radius);\n  color: var(--code-text);\n}\n<\/style>\n\n<div class=\"wp_blog_container wp_blog_theme\"> \n    <h1 class=\"wp_blog_main-heading\"><\/h1>\n    <div class=\"wp_blog_explanation\">\n        <h2>Problem Statement:<\/h2>\n        <p>\n            Given the <code>root<\/code> of a binary tree, invert the tree, and return <i>its root<\/i>.\n        <\/p>\n                <h2>Examples:<\/h2>\n                <h3>Example 1:<\/h3>\n               <img decoding=\"async\" src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-31-at-7.04.24\u202fPM.png\" alt=\"\">\n                <p><strong>Input:<\/strong> root = [4,2,7,1,3,6,9]<\/p>\n                <p><strong>Output:<\/strong> [4,7,2,9,6,3,1]<\/p>\n\n                <h3>Example 2:<\/h3>\n               <img decoding=\"async\" src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-31-at-4.57.54\u202fPM.png\" alt=\"\">\n                <p><strong>Input:<\/strong> root = [2,1,3]]<\/p>\n                <p><strong>Output:<\/strong> [2,3,1]<\/p>\n\n                <h3>Example 3:<\/h3>\n                <p><strong>Input: <\/strong>root = []<\/p>\n                <p><strong>Output: <\/strong>[]<\/p>\n\n                    <h2>Constraints:<\/h2>\n                    <ul>\n                      <li>The number of nodes in the tree is in the range <code>[0, 100]<\/code>.<\/li>\n                      <li><code>-100 <= Node.val <= 100<\/code><\/li>\n                    <\/ul>\n\n                <h2>Approach<\/h2>\n            <ul>\n                <li><strong>Base Case:<\/strong> If the current node is <code>null<\/code>, return <code>null<\/code>.<\/li>\n                <li><strong>Swap<\/strong> the left and right child of the current node.<\/li>\n                <li><strong>Recurse<\/strong> on the left and right subtrees.<\/li>\n                <li>Finally, return the root node (which now has inverted subtrees).<\/li>\n            <\/ul>\n\n                <h2>Time Complexity:<\/h2>\n                <li>\n                  <p><strong>Time Complexity = O(n)<\/strong>\n                  <\/li>\n                <h2>Space Complexity:<\/h2>\n                <li>\n                  <p><strong>Space Complexity = O(n)<\/strong><\/p>\n                <\/li>\n\n<h2>Dry Run<\/h2>\n<div style=\"background: #f9f9f9; padding: 10px; border: 1px solid #ccc; font-family: monospace;\">\n\n<b>Initial Queue:<\/b> [2, 3]<br><br>\n\n<b>Step 1:<\/b><br>\n\u2192 p1 = 2, p2 = 3<br>\n\u2192 p1 and p2 are not null \u2192 OK<br>\n\u2192 Compare p1.val (2) != p2.val (3)<br>\n\u2192 Values are not equal \u2192 <b>Return false<\/b><br><br>\n\n<b>Function exits early.<\/b><br>\n<b>Final Result:<\/b> false\n\n<\/div>\n\n    \n    <!-- <h2>Visualisation:<\/h2>\n        <img decoding=\"async\" src=\"https:\/\/namastedev.com\/blog\/wp-content\/uploads\/2025\/07\/Screenshot-2025-07-19-at-5.23.43\u202fPM.png\" alt=\"longest\" \/> -->\n    <\/div>\n    \n\n    <div class=\"wp_blog_code-tabs-container\">\n        <div class=\"wp_blog_code-tabs-header\">\n            <button class=\"wp_blog_code-tab-button active\" data-lang=\"js\">JavaScript<\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"py\">Python<\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"java\">Java<\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"cpp\">C++<\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"c\">C<\/button>\n            <button class=\"wp_blog_code-tab-button\" data-lang=\"cs\">C#<\/button>\n        <\/div>\n\n        <!-- JavaScript -->\n        <div class=\"wp_blog_code-tab-content active\" data-lang=\"js\">\n            <pre><code class=\"language-javascript\">\nvar isSymmetric = function(root) {\n    let q = [root.left, root.right];\n    while(q.length) {\n        let p1 = q.shift();\n        let p2 = q.shift();\n        if(!p1 && !p2) continue;\n        if(!p1 || !p2) return false;\n        if(p1.val != p2.val) return false;\n        q.push(p1.left, p2.right);\n        q.push(p1.right, p2.left);\n    }\n    return true;\n};\n     <\/code><\/pre>\n        <\/div>\n\n        <!-- Python -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"py\">\n            <pre><code class=\"language-python\">\nclass TreeNode:\n    def __init__(self, val=0, left=None, right=None):\n        self.val = val\n        self.left = left\n        self.right = right\ndef invertTree(root):\n    if not root:\n        return root\n    root.left, root.right = root.right, root.left\n    invertTree(root.left)\n    invertTree(root.right)\n    return root\n            <\/code><\/pre>\n        <\/div>\n\n        <!-- Java -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"java\">\n            <pre><code class=\"language-java\">\nclass TreeNode {\n    int val;\n    TreeNode left;\n    TreeNode right;\n}\nclass Solution {\n    public TreeNode invertTree(TreeNode root) {\n        if (root == null) return root;\n        TreeNode temp = root.left;\n        root.left = root.right;\n        root.right = temp;\n        invertTree(root.left);\n        invertTree(root.right);\n        return root;\n    }\n}\n     <\/code><\/pre>\n        <\/div>\n\n        <!-- C++ -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"cpp\">\n            <pre><code class=\"language-cpp\">\nstruct TreeNode {\n    int val;\n    TreeNode *left;\n    TreeNode *right;\n};\nTreeNode* invertTree(TreeNode* root) {\n    if (!root) return root;\n    TreeNode* temp = root->left;\n    root->left = root->right;\n    root->right = temp;\n    invertTree(root->left);\n    invertTree(root->right);\n    return root;\n}\n    <\/code><\/pre>\n        <\/div>\n\n        <!-- C -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"c\">\n            <pre><code class=\"language-c\">\nstruct TreeNode {\n    int val;\n    struct TreeNode* left;\n    struct TreeNode* right;\n};\nstruct TreeNode* invertTree(struct TreeNode* root) {\n    if (!root) return root;\n    struct TreeNode* temp = root->left;\n    root->left = root->right;\n    root->right = temp;\n    invertTree(root->left);\n    invertTree(root->right);\n    return root;\n}\n            <\/code><\/pre>\n        <\/div>\n\n        <!-- C# -->\n        <div class=\"wp_blog_code-tab-content\" data-lang=\"cs\">\n            <pre><code class=\"language-csharp\">\npublic class TreeNode {\n    public int val;\n    public TreeNode left;\n    public TreeNode right;\n}\npublic class Solution {\n    public TreeNode InvertTree(TreeNode root) {\n        if (root == null) return root;\n        TreeNode temp = root.left;\n        root.left = root.right;\n        root.right = temp;\n        InvertTree(root.left);\n        InvertTree(root.right);\n        return root;\n    }\n}\n            <\/code><\/pre>\n        <\/div>\n    <\/div>\n<\/div>\n\n<script>\n    document.addEventListener(\"DOMContentLoaded\", () => {\n        const buttons = document.querySelectorAll(\".wp_blog_code-tab-button\");\n        const contents = document.querySelectorAll(\".wp_blog_code-tab-content\");\n\n        buttons.forEach((button) => {\n            button.addEventListener(\"click\", () => {\n                const lang = button.getAttribute(\"data-lang\");\n\n                buttons.forEach((btn) => btn.classList.remove(\"active\"));\n                contents.forEach((content) =>\n                    content.classList.remove(\"active\")\n                );\n\n                button.classList.add(\"active\");\n                document\n                    .querySelector(`.wp_blog_code-tab-content[data-lang=\"${lang}\"]`)\n                    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Examples: Example 1: Input: root = [4,2,7,1,3,6,9] Output: [4,7,2,9,6,3,1] Example 2: Input: root = [2,1,3]] Output: [2,3,1] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 100].<\/p>\n","protected":false},"author":108,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[322,176,175,211,174,172,173],"tags":[],"class_list":["post-8792","post","type-post","status-publish","format-standard","category-algorithms-and-data-structures","category-csharp","category-cplusplus","category-data-structures","category-java","category-javascript","category-python"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/8792","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/users\/108"}],"replies":[{"embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/comments?post=8792"}],"version-history":[{"count":2,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/8792\/revisions"}],"predecessor-version":[{"id":8798,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/posts\/8792\/revisions\/8798"}],"wp:attachment":[{"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/media?parent=8792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/categories?post=8792"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/namastedev.com\/blog\/wp-json\/wp\/v2\/tags?post=8792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}