<pre class="shiki github-dark shaku"><code>function traverse(root) { const verticales = new Map(); fillverticales(root, verticales, 0, 0, 0); const keys = Array.from(verticales.keys()).sort((a, b) =&gt; a - b); const result = []; for (const key of keys) { const nodes = verticales.get(key) .sort((a, b) =&gt; { if (a.depth !== b.depth) { return a.depth - b.depth; } return a.parentPosition - b.parentPosition; }) .map(item =&gt; item.value); result.push(...nodes); } return result;}const fillverticales = (node, verticales, position, parentPosition, depth) =&gt; { if (!node) { return; } if (!verticales.has(position)) { verticales.set(position, []); } verticales.get(position).push({ value: node.value, depth, parentPosition }); fillverticales(node.left, verticales, position - 1, position, depth + 1); fillverticales(node.right, verticales, position + 1, position, depth + 1);}</code></pre>

Easy to understand solution

Traverse a binary tree vertically from left to right, from top to bottom, the binary tree contains positive integers as node values. [https://cdn.bfe.…