java面试题：如何求二叉树中节点的最大距离+层序遍历

问题描述：求二叉树中距离最远的两个 节点之间的距离。。

class Node{public int data;public Node left;public Node right;public int leftMaxDistance;public int rightMaxDistance;public Node(int data){this.data=data;this.left=null;this.right=null;}}public class BinaryTree{private int maxLen=0;private Node root;public BinaryTree() {root=null;}private int max(int a,int b){return a>b?a:b;}private  void FindMaxDistance(Node root){if(root==null)return ;if(root.left==null)root.leftMaxDistance=0;if(root.right==null)root.rightMaxDistance=0;if(root.left!=null)FindMaxDistance(root.left);if(root.right!=null)FindMaxDistance(root.right);if(root.left!=null){root.leftMaxDistance=max(root.left.leftMaxDistance,root.left.leftMaxDistance)+1;}if(root.right!=null){root.rightMaxDistance=max(root.right.rightMaxDistance,root.right.rightMaxDistance)+1;}if(root.leftMaxDistance+root.rightMaxDistance>maxLen){maxLen=root.leftMaxDistance+root.rightMaxDistance;}}//向二叉排序树插入节点private void insertBtree(int data){Node newNode=new Node(data);if(root==null){root=newNode;}else{Node current=root;Node parent;while(true){parent=current;if(data<current.data){current=current.left;if(current==null){parent.left=newNode;return;}}else{current=current.right;if(current==null){parent.right=newNode;return;}}}//while}}//将数值输入构建二叉树public void buildTree(int[] data){for (int i = 0; i < data.length; i++) {insertBtree(data[i]);}}

//层序遍历二叉树public void layerTranverse(){if(this.root==null){return;}Queue<Node> q=new LinkedList<Node>();q.add(this.root);while(!q.isEmpty()){Node n=q.poll();System.out.print(n.data+" ");if(n.left!=null)q.add(n.left);if(n.right!=null)q.add(n.right);}}public static void main(String[] args) {int[] data={5,3,2,4,7,6,8};BinaryTree bTree=new BinaryTree();bTree.buildTree(data);bTree.FindMaxDistance(bTree.root);System.out.println(bTree.maxLen);

bTree.layerTranverse();

}}