hello-algo/codes/javascript/chapter_backtracking/preorder_traversal_i_compact.js

/**
 * File: preorder_traversal_i_compact.js
 * Created Time: 2023-05-09
 * Author: Justin (xiefahit@gmail.com)
 */

const { arrToTree } = require('../modules/TreeNode');
const { printTree } = require('../modules/PrintUtil');

/* 前序遍历：例题一 */
function preOrder(root, res) {
  if (root === null) {
    return;
  }
  if (root.val === 7) {
    // 记录解
    res.push(root);
  }
  preOrder(root.left, res);
  preOrder(root.right, res);
}

// Driver Code
const root = arrToTree([1, 7, 3, 4, 5, 6, 7]);
console.log("\n初始化二叉树");
printTree(root);

// 前序遍历
const res = [];
preOrder(root, res);

console.log("\n输出所有值为 7 的节点");
console.log(res.map(node => node.val));