/*

实现一颗树

  结点类:Tree

     包含左子树left,右子树right,根节点root,缺省为null

     构造设置value

  树类:Trees

    构造:默认根节点为null

    insert:

        如果当前根节点不存在,则将传进来的节点存为根节点

        如果当前根节点存在,执行InsertTree

    insertTree(rootNode,newTree):

        1 如果新树value小于根节点value,放到根节点的左边,如果根节点左子树已经存在,以根节点左子树为根节点继续递归

        2 如果新树value大于等于根节点value,放到根节点右边,如果根节点右子树已经存在,以根节点右子树为根节点继续递归

*/

class Tree {

    left = null;

    right = null;

    root = null;

    constructor(_value) { this.value = _value;}

}

class Trees {

    constructor() { this.root = null; }

    insert(value) {this.root ? this.insertTree(this.root, new Tree(value)) : this.root = new Tree(value);}

    insertTree(rootNode, newTree) {

        newTree.value < rootNode.value ?

        (rootNode.left ? this.insertTree(rootNode.left, newTree) : rootNode.left = newTree)

        :

        (rootNode.right ? this.insertTree(rootNode.right, newTree) : rootNode.right = newTree);

    }

}

let tree = new Trees();

for (let i = 20; i > 0; i -= 2) {

    tree.insert(i - 1);

    tree.insert(i);

}

console.log(tree);