js数据结构之二叉树的详细实现方法

function Node (data, left, right) {
    this.data = data;
    this.left = left;
    this.right = right;
    this.show = function () {
        return this.data;
    };
}


function BST () {
    this.root = null;
    this.insert = function (data) {
        var node = new Node(data, null, null);
        if (this.root === null) {
            this.root = node;
        } else {
            var current = this.root;
            var parent;
            while (true) {
                parent = current;
                if (data < current.data) {
                    current = current.left;
                    if (current === null) {
                        parent.left = node;
                        break;
                    }
                } else {
                    current = current.right;
                    if(current === null) {
                        parent.right = node;
                        break;
                    }
                }
            }
        }
    };
    // 中序遍历
    this.inOrder = function (node) {
        if (node !== null) {
            this.inOrder(node.left);
            console.log(node.show());
            this.inOrder(node.right);
        }
    };
    // 先序遍历
    this.preOrder = function (node) {
        if (node !== null) {
            console.log(node.show());
            this.preOrder(node.left);
            this.preOrder(node.right);
        }
    };
    // 后序遍历
    this.afterOrder = function (node) {
        if (node !== null) {
            this.afterOrder(node.left);
            this.afterOrder(node.right);
            console.log(node.show());
        }
    };

    this.getMin = function () {
        var current = this.root;
        while (current.left !== null) {
            current = current.left;
        }
        return current.data;
    };


    this.getMax = function () {
        var current = this.root;
        while (current.right !== null) {
            current = current.right;
        }
        return current.data;
    };

    this.find = function (data) {
        var current = this.root;
        while (current !== null) {
            if (data < current.data) {
                current = current.left;
            } else if (data > current.data) {
                current = current.right;
            } else {
                return current;
            }
        }
        return null;
    };

    

    this.remove = function (data) {
        this.root = this._removeNode(this.root, data); //将根节点转换
    };

    this._getSmallest = function (node) {
        while(node.left!=null){
            node=node.left;
        }
        return node;
    };


    this._removeNode = function (node, data) {
        if (node === null) {
            return null;
        }
        if (data === node.data) {
            // 如果没有子节点
            if (node.right === null && node.left === null) {
                return null;
            }
            // 如果没有左子节点
            if (node.left === null) {
                return node.right;//直接指向其右节点
            }
            // 如果没有右子节点
            if (node.right === null) {
                return node.left;
            }
            // 如果有两个节点
            if (node.right !== null && node.left !== null) {
                var tempNode = this._getSmallest(node.right);   // 找到最小的右节点
                node.data = tempNode.data;
                node.right = this._removeNode(node.right, tempNode.data);    // 依次寻找
                return node;
            }
        } else if (data < node.data){
            node.left = this._removeNode(node.left, data);
            return node;
        } else {
            node.right = this._removeNode(node.right, data);
            return node;
        }
    };
}

var bst = new BST ();
bst.insert(40);
bst.insert(20);
bst.insert(70);
bst.insert(60);
bst.insert(75);
bst.insert(71);
bst.insert(73);

bst.inOrder(bst.root);
bst.remove(70);
console.log("----------------");
bst.inOrder(bst.root);
console.log("----------------");
console.log(bst.find(73))