1676-lowest-common-ancestor-of-a-binary-tree-iv.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @param {TreeNode[]} nodes
 * @return {TreeNode}
 */
const lowestCommonAncestor = function(root, nodes) {
  if (root == null) return root
  for(let e of nodes) {
    if(root === e) return root
  }
  const left = lowestCommonAncestor(root.left, nodes)
  const right = lowestCommonAncestor(root.right, nodes)
  if(left && right) return root
  return left ? left : right
};

// another

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @param {TreeNode[]} nodes
 * @return {TreeNode}
 */
 const lowestCommonAncestor = function(root, nodes) {
  const set = new Set(nodes)
  return dfs(root)
  
  function dfs(node) {
    if(node == null) return node
    const left = dfs(node.left)
    const right = dfs(node.right)

    if(set.has(node)) return node
    if(left && right) return node
    return left || right
  }
};