用JS实现二叉树

Posted 2020-12-03 SofiaTJU

用JS实现二叉树数据结构, 完成遍历、查找最大/小值、查找特定值以及删除节点的操作。

参考博文

//定义节点
class Node {
    constructor(data){
        this.root = this;
        this.data = data;
        this.left = null;
        this.right = null
    }
}
//创建二叉搜索树(BST)）
class BinarySearchTree {
    constructor(){
    this.root = null
    }
    //插入节点
    insert(data){
        const newNode = new Node(data);
        const insertNode = (node,newNode) => {
            if (newNode.data < node.data){
                if(node.left === null){
                    node.left = newNode
                }else {
                    insertNode(node.left,newNode)
                }
            }else {
                if(node.right === null){
                    node.right = newNode
                }else{
                    insertNode(node.right,newNode)
                }

            }
        };
        if(!this.root){
            this.root = newNode
        }else {
            insertNode(this.root,newNode)

        }
    }
    //中序遍历
    inOrder(){
        let backs = [];
        const inOrderNode = (node,callback) => {
            if(node !== null){
                inOrderNode(node.left,callback);
                backs.push(callback(node.data));
                inOrderNode(node.right,callback)
            }
        };
        inOrderNode(this.root,callback);
        function callback(v){
            return v
        }
        return backs
    }
    //前序遍历
    preOrder(){
        let backs = [];
        const preOrderNode = (node,callback) => {
            if(node !== null){
                backs.push(callback(node.data));
                preOrderNode(node.left,callback);
                preOrderNode(node.right,callback)
            }
        };
        preOrderNode(this.root,callback);
        function callback(v){
            return v
        }
        return backs
    }
    //后序遍历
    postOrder(){
        let backs = [];
        const postOrderNode = (node,callback) => {
            if(node !== null){
                postOrderNode(node.left,callback);
                postOrderNode(node.right,callback);
                backs.push(callback(node.data))
            }
        };
        postOrderNode(this.root,callback);
        function callback(v){
            return v
        }
        return backs
    }
    //查找最小值
    getMin(node){
        const minNode = node => {
            return node? (node.left? minNode(node.left):node):null
        };
        return minNode( node || this.root)
    }
    //查找最大值
    getMax(node){
        const minNode = node => {
            return node? (node.right? minNode(node.right):node):null
        };
        return minNode(node || this.root)
    }
    //查找特定值
    find(data){
        const findNode = (node,data) => {
            if(node===null) return false;
            if(node.data===data) return node;
            return findNode((data < node.data)? node.left: node.right,data)
        };
        return findNode(this.root,data)

    }
    //删除节点
    remove(data){
        const removeNode = (node,data) => {
            if(node === null) return null;
            if(node.data === data){
                if(node.left === null && node.right === null) return null;
                if(node.left === null) return node.right;
                if(node.right === null) return node.left;
                if(node.left !==null && node.right !==null){
                let _node = this.getMin(node.right);
                node.data = _node.data;
                node.right = removeNode(node.right,data);
                return node
                }
            } else if(data < node.data){
                node.left=removeNode(node.left,data);
                return node
            } else {
                node.right=removeNode(node.right,data);
                return node
            }
        };
        return removeNode(this.root,data)
    }
}
 //创建BST
const tree = new BinarySearchTree();
tree.insert(11);
tree.insert(7);
tree.insert(5);
tree.insert(3);
tree.insert(9);
tree.insert(8);
tree.insert(10);
tree.insert(13);
tree.insert(12);
tree.insert(14);
tree.insert(20);
tree.insert(18);
tree.insert(25);
console.log(tree);
console.log(tree.root);
//中序遍历BST
console.log(tree.inOrder());
//前序遍历BST
console.log(tree.preOrder());
//后序遍历BST
console.log(tree.postOrder());
//搜索最小值
console.log(tree.getMin());
//搜索最大值
console.log(tree.getMax());
//查找特定值
console.log(tree.find(2));
console.log(tree.find(3));
console.log(tree.find(20));
//删除节点，返回新的二叉树，不改变原来的二叉树
console.log(tree.remove(11));
a=tree.remove(11);
console.log(a.root);
console.log(tree);