LC.二叉树的中序遍历

二叉树

代码

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number[]}
 */
const inOrder = (root, res) => {
  if (root === null) {
    return null;
  }
  inOrder(root.left, res);
  res.push(root.val);
  inOrder(root.right, res);
}
var inorderTraversal = function (root) {
  const res = []
  inOrder(root, res);
  return res;
};