添加二叉搜索树

Author: wangjieCode

.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "pwa-chrome",
+            "request": "launch",
+            "name": "Launch Chrome against localhost",
+            "url": "http://localhost:8080",
+            "webRoot": "${workspaceFolder}"
+        }
+    ]
+}

main.js

@@ -0,0 +1,2 @@
+import './树/Bst'
+

string/test.js renamed to string/string.js

@@ -0,0 +1,27 @@
+import { Bst } from "../树/Bst"
+
+
+describe("二叉搜索树", () => {
+    const bts = new Bst()
+    bts.add(7)
+    bts.add(4)
+    bts.add(9)
+    bts.add(2)
+    bts.add(5)
+    bts.add(8)
+    bts.add(11)
+    bts.add(3)
+    bts.add(12)
+    test("是否包含某个元素", () => {
+        expect( bts.contains(1) ).toBe(false)
+        expect( bts.contains(1) ).toBe(false)
+        expect( bts.contains(5) ).toBe(true)
+        expect( bts.contains(3) ).toBe(true)
+    })
+    test("清空搜索树", () => {
+        bts.clear()
+        expect( bts.contains(7) ).toBe(false)
+        expect( bts.contains(5) ).toBe(false)
+        expect( bts.contains(3) ).toBe(false)
+    })
+})

test/bst.test.js

@@ -0,0 +1,80 @@
+class Node {
+    target = null
+    leftNode = null
+    rightNode = null
+    parent = null
+    constructor(target, parent) {
+        this.target = target
+        this.parent = parent
+    }
+}
+
+export class Bst {
+    #root = null
+    size = 0
+
+    isEmpty() {
+        return this.size === 0;
+    }
+    clear() {
+        this.#root = null
+    }
+    add(target) {
+        // 添加根节点
+        if (this.#root == null) {
+            this.#root = new Node(target, null)
+            this.size++
+            return
+        }
+        let node = this.#root;
+        let parent = node
+        let ins = 0;
+        while(node != null){
+            ins = this.compare(target, node.target)
+            parent = node
+            if(ins > 0){    
+                node = node.rightNode
+            } else if(ins < 0){
+                node = node.leftNode
+            } else {
+                return
+            }
+        }
+        const newNode = new Node(target,parent)
+        if(ins > 0){
+            parent.rightNode = newNode
+        } else {
+            parent.leftNode = newNode
+        }
+        this.size++
+    }
+    compare(e1, e2) {
+        return e1 - e2
+    }
+    contains(target) {
+        let root = this.#root
+        while(root != null){
+            if(root.target === target) return true;
+            if(root.target > target){
+                root = root.leftNode
+            }else {
+                root = root.rightNode
+            }
+        }
+        return false
+    }
+}
+
+const bts = new Bst()
+bts.add(7)
+bts.add(4)
+bts.add(9)
+bts.add(2)
+bts.add(5)
+bts.add(8)
+bts.add(11)
+bts.add(3)
+bts.add(12)
+
+// console.log( bts.contains(29) )
+// console.log(bts)

树/Bst.js

@@ -0,0 +1,9 @@
+# 树
+> 应用: 文件夹结构，组织架构，搜索引擎，Dom节点 等等
+
+![](images/2021-06-02-09-15-43.png)
+![](images/2021-06-02-09-18-49.png)
+![](images/2021-06-02-09-20-16.png)
+
+## 二叉树(Binary tree)
+> 每个节点的度最多为2 即最多有两个子树