<pre class="shiki github-dark shaku"><code>// This is the type for the node// type Node = null | {// value: number// left: Node// right: Node// }</code></pre>
<pre class="shiki github-dark shaku"><code>/** * Recursion * @param {Node} node * @returns {Node} */function invert(node) { // your code here if (!node) return node; [node.left, node.right] = [invert(node.right), invert(node.left)]; return node;}</code></pre>
<pre class="shiki github-dark shaku"><code>/** * Stack (Winner): we can also use Queue, but array.pop has better performance * @param {Node} node * @returns {Node} */function invert(node) { const stack = [node]; while (stack.length) { const current = stack.pop(); if (current) { [current.left, current.right] = [current.right, current.left]; stack.push(current.left, current.right); } } return node;}</code></pre>

simple and elegant (both recursion and stack)

Google

Can you invert a binary tree and get an offer from Google? > Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert …