JavaScript Data Structure: Binary Tree & tree generator All In One

JavaScript Data Structure: Binary Tree & tree generator All In One

js binary tree generator

Binary Tree Generator / 二叉树生成器

treeGenerator

binary-tree-generator.ts

class TreeNode {
  public val: TreeNode;
  public left: TreeNode | null;
  public right: TreeNode | null;
  constructor(value?) {
    this.val = value ?? null;
    this.left = null;
    this.right = null;
  }
}

// 二叉搜索树 / 排序二叉树
class BinaryTreeGenerator {
  public root;
  constructor() {
    this.root = null;
  }
  insert (key) {
    if(this.root === null) {
      this.root = new TreeNode(key);
    } else {
      this.insertNode(this.root, key)
    }
  }
  insertNode (node, key) {
    if(key < node.val) {
      // left
      if(node.left === null) {
        node.left = new TreeNode(key);
      } else {
        this.insertNode(node.left, key)
      }
    } else {
      // right
      if(node.right === null) {
        node.right = new TreeNode(key);
      } else {
        this.insertNode(node.right, key)
      }
    }
  }
  // root
  // insert
  // search
  // traversal ...
  // preTraversal ...
  // InorderTraversal ...
  // postTraversal ...
  // min
  // max
}

binary-tree-generator.js

class TreeNode {
  constructor(value) {
    this.val = value;
    this.left = null;
    this.right = null;
  }
}

// 二叉搜索树 / 排序二叉树
class BinaryTreeGenerator {
  constructor() {
    this.root = null;
  }
  insert (key) {
    if(this.root === null) {
      this.root = new TreeNode(key);
    } else {
      this.insertNode(this.root, key)
    }
  }
  insertNode (node, key) {
    if(key < node.val) {
      // left
      if(node.left === null) {
        node.left = new TreeNode(key);
      } else {
        this.insertNode(node.left, key)
      }
    } else {
      // right
      if(node.right === null) {
        node.right = new TreeNode(key);
      } else {
        this.insertNode(node.right, key)
      }
    }
  }
}

// test
const tree = new BinaryTreeGenerator();
const keys = [1,null,2,3];
for (const key of keys) {
  tree.insert(key);
}
console.log(`tree = `, tree);
console.log(`tree.root = `, tree.root);

树的遍历

https://leetcode.cn/leetbook/read/data-structure-binary-tree/xe17x7/

// Definition for a binary tree node.
class TreeNode {
  val: number;
  left: TreeNode | null;
  right: TreeNode | null;
  constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
    this.val = (val === undefined ? 0 : val);
    this.left = (left === undefined ? null : left);
    this.right = (right === undefined ? null : right);
  }
}

"use strict";

/**
 *
 * @author xgqfrms
 * @license MIT
 * @copyright xgqfrms
 * @created 2022-10-10
 * @modified
 *
 * @description树 & 遍历
 * @difficulty Easy
 * @ime_complexity O(n)
 * @space_complexity O(n)
 * @augments
 * @example
 * @link https://leetcode.cn/leetbook/read/data-structure-binary-tree/xe17x7/
 * @solutions
 *
 * @best_solutions
 *
 */

// export {};

const log = console.log;

// Definition for a binary tree node.
class TreeNode {
  constructor(val , left, right) {
    this.val = (val === undefined ? 0 : val);
    this.left = (left === undefined ? null : left);
    this.right = (right === undefined ? null : right);
  }
}


// bug ❌
const treeGenerator = (list) => {
  if(!list.length) return [];
  // let tree = new TreeNode(list[0]);
  let tree = new TreeNode();
  let temp = tree;
  console.log(`tree =`, tree);
  for (const [i, item] of list.entries()) {
    // console.log(`item =`, item);
    // if(i === 0) {
    //   continue;
    // }
    temp.val = item;
    console.log(`temp 1 =`, temp);
    if(item !== null) {
      temp.right = new TreeNode(null);
      temp.left = new TreeNode(list[i + 1]);
      if(i < list.length - 1) {
          temp = temp.left;
      }
    } else {
      temp.left = new TreeNode(null);
      temp.right = new TreeNode(list[i + 1]);
      if(i < list.length - 1) {
        temp = temp.right;
      }
    }
    console.log(`temp 2 =`, temp);
  }
  console.log(`tree ?=`, tree);
  return tree;
}

// test
treeGenerator([1,null,2,3]);

$ npx ts-node ./tree-generator.ts

https://leetcode.cn/leetbook/read/data-structure-binary-tree/xecaj6/

LeetCode

function preOrderTraversal(root: TreeNode | null): number[] {
  if(!root) return [];
  // 144. 二叉树的前序遍历: root, left, right
  // DFS 深度优先搜索
  function dfs(head: TreeNode | null, result: number[]) {
    if(!head) {
      return;
    }
    result.push(head.val);
    dfs(head.left, result)
    dfs(head.right, result);
  }
  let result: number[] = [];
  dfs(root, result);
  return result;
};

https://leetcode.com/problems/binary-tree-preorder-traversal/

https://leetcode.cn/problems/binary-tree-preorder-traversal/

LeetCode 二叉树生成器 / Binary Tree Generator

ChatGPT ✅

https://chat.openai.com/chat

class TreeNode {
  constructor(val) {
    this.val = val;
    this.left = this.right = null;
  }
}

function createBinaryTree(arr, i = 0) {
  if (i >= arr.length || arr[i] === null) return null;
  let node = new TreeNode(arr[i]);
  node.left = createBinaryTree(arr, 2 * i + 1);
  node.right = createBinaryTree(arr, 2 * i + 2);
  return node;
}

const arr = [3, 9, 20, null, null, 15, 7];
const root = createBinaryTree(arr);
console.log(root);

https://leetcode.com/problems/maximum-depth-of-binary-tree/

https://stackoverflow.com/questions/75295344/its-possible-to-create-a-function-auto-generator-this-special-test-case-binary

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refs

js binary tree generator / js 二叉树生成器

https://www.cnblogs.com/xgqfrms/p/17052456.html

https://github.com/xgqfrms/leetcode/blob/f9d93e0f0151b3c2eb652e09e78c2ccf6de23d19/js-solutions/144 binary-tree-preorder-traversal.ts

/Users/xgqfrms-mm/Documents/github/leetcode/js-solutions/144 binary-tree-preorder-traversal.ts

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