js数据结构与算法——二叉树

Posted 2021-02-11 面包_girl

function BinaryTree(){
            var Node = function(key){
                this.key = key; //值
                this.left = null; //左箭头
                this.right = null; //右箭头
            }
            //根节点
            var root = null;

            var insertNode = function(oldNode,newNode){
                if(newNode.key < oldNode.key){
                    if(oldNode.left === null){
                        oldNode.left = newNode
                    }else{
                        insertNode(oldNode.left,newNode)//递归查找
                    }
                }else{
                    if(oldNode.right === null){
                        oldNode.right = newNode
                    }else{
                        insertNode(oldNode.right,newNode);
                    }
                }
            }

            //插入节点
            this.insert = function(key) {
                var newNode = new Node(key);
                if(root === null){
                    root = newNode;
                }else{
                    insertNode(root,newNode)
                }
            }

            //中序排列
            this.inOrderTraverse = function(callback){
                inOrderTraverseNode(root,callback)
            }

            //中序排序辅助函数

            var inOrderTraverseNode = function(node,callback){
                if(node !== null){
                    inOrderTraverseNode(node.left,callback);//遍历左节点
                    callback(node.key);//遍历根节点，中节点
                    inOrderTraverseNode(node.right,callback);//遍历右节点
                }
            }

            //先序遍历,先访问节点本身在遍历左节点，最后遍历右节点

            this.preOrderTraverse = function(callback){
                preOrderTraverseNode(root,callback);
            }

            var preOrderTraverseNode = (node,callback)=>{
                if(node !== null){
                    callback(node.key);
                    preOrderTraverseNode(node.left,callback);
                    preOrderTraverseNode(node.right,callback);
                }
            }

            //后序遍历，先访问节点的后代节点，再访问节点本身

            this.postOrderTraverse = function(callback){
                postOrderTraverseNode(root,callback);
            }

            var postOrderTraverseNode = (node,callback) =>{
                if(node !== null){
                    postOrderTraverseNode(node.left,callback);
                    postOrderTraverseNode(node.right,callback);
                    callback(node.key);
                }
            }
            
            //搜索最大值，最小值
            this.min = function(){
                return minNode(root);
            }

            var minNode = (node)=>{
                if(node){
                    while(node && node.left !== null){
                        node = node.left;
                    }
                    return node.key
                }
                return null;
            }

            this.max = function(){
                return maxNode(root);
            }

            var maxNode = (node) => {
                if(node){
                    while(node && node.right !== null){
                        node = node.right;
                    }
                    return node.key
                }
                return null;
            }
            //搜索一个特定的值

            this.search = function(key){
                return searchNode(root,key);
            }

            var searchNode = (node,key) =>{
                if(node === null){
                    return false;
                }
                if(key < node.key){
                    return searchNode(node.left,key)
                } else if( key > node.key){
                    return searchNode(node.right,key);
                }else{
                    return true;
                }
            }

            //移除一个节点

            this.remove = function(key){
                return removeNode(root,key);
            }

            var removeNode = (node,key) =>{
                if(node === null){
                    return false
                }
                if(key < node.key){
                    node.left = removeNode(node.left,key);
                    return node
                }else if(key > node.key){
                    node.right = removeNode(node.right,key);
                    return node;
                }else{
                    //第一种情况  一个叶子节点
                    if(node.left === null && node.right === null){
                        node = null;
                        return node;
                    }
                    //第二种情况  一个只有一个子节点的节点

                    if(node.left === null){
                        node = node.right;
                        return node;
                    }else if(node.right === null){
                        node = node.left;
                        return node;
                    }

                    //第三种情况  一个有两个子节点的节点
                    var aux = findMinNode(node.right);
                    node.key = aux.key;
                    node.right = removeNode(node.right,aux.key);
                    return node;
                }
            }

            var findMinNode = (node)=>{
                if(node){
                    while(node && node.left !== null){
                        node = node.left;
                    }
                    return node
                }
                return null;
            }

        }    

        let node = [8,3,10,1,6,14,4,7,13];
        var binaryTree = new BinaryTree();
        node.forEach((key)=>{
            binaryTree.insert(key);
        })

       var printNode = (val) => {
           console.log(val)
       }
        binaryTree.inOrderTraverse(printNode) //中序遍历
        binaryTree.preOrderTraverse(printNode) //先序遍历
        binaryTree.postOrderTraverse(printNode) //后序遍历
        
        console.log(binaryTree.min() + ‘: min‘)
        console.log(binaryTree.max() + ‘: max‘)
        console.log(binaryTree.search(8) + ‘: search‘)
        console.log(binaryTree.remove(8) )