代码:
package com.qhong; import java.util.*; public class Main { public static void main(String[] args) { int[] array=new int[] {0,1,2,3,4,5,6,7,8,9,10,11,12,13}; TreeNode root=Tool.createTree(array); Print.PrintTreeNode(root); } } class TreeNode { int val; TreeNode left; TreeNode right; TreeNode(int x) { val = x; } } class Tool{ /* * 构建完全二叉树 */ public static TreeNode createTree(int[] array){ List<TreeNode> nodeList=new LinkedList<TreeNode>(); for(int nodeIndex=0;nodeIndex<array.length;nodeIndex++){ nodeList.add(new TreeNode(array[nodeIndex])); } for(int parentIndex=0;parentIndex<=array.length/2-1;parentIndex++){ nodeList.get(parentIndex).left =nodeList.get(parentIndex*2+1); //防止是非完全二叉树 if((parentIndex*2+2)<array.length) { nodeList.get(parentIndex).right = nodeList.get(parentIndex * 2 + 2); } } // // int lastParentIndex=array.length/2-1; // nodeList.get(lastParentIndex).left =nodeList.get(lastParentIndex*2+1); // // if(array.length%2==1){ // nodeList.get(lastParentIndex).right =nodeList.get(lastParentIndex*2+2); // } return nodeList.get(0); } } class Print{ //打印TreeNode public static void PrintTreeNode(TreeNode root){ ArrayList arrayList=PrintFromTopToBottom(root); printTree(arrayList,arrayList.size()); } //转换TreeNode为ArrayList private static ArrayList<Integer> PrintFromTopToBottom(TreeNode root) { ArrayList<Integer> list = new ArrayList(); if(root == null) return list; Queue<TreeNode> queue = new LinkedList(); queue.offer(root); while(!queue.isEmpty()){ TreeNode treeNode = queue.poll(); list.add(treeNode.val); if(treeNode.left != null) queue.offer(treeNode.left); if(treeNode.right != null) queue.offer(treeNode.right); } return list; } //以树形打印ArrayList private static void printTree(ArrayList array,int len){ int layers = (int)Math.floor(Math.log((double)len)/Math.log((double)2))+1; //树的层数 int maxWidth = (int)Math.pow(2,layers)-1; //树的最大宽度 int endSpacing = maxWidth; int spacing; int numberOfThisLayer; for(int i=1;i<=layers;i++){ //从第一层开始,逐层打印 endSpacing = endSpacing/2; //每层打印之前需要打印的空格数 spacing = 2*endSpacing+1; //元素之间应该打印的空格数 numberOfThisLayer = (int)Math.pow(2, i-1); //该层要打印的元素总数 int j; for(j=0;j<endSpacing;j++){ System.out.print(" "); } int beginIndex = (int)Math.pow(2,i-1)-1; //该层第一个元素对应的数组下标 for(j=1;j<=numberOfThisLayer;j++){ System.out.print(array.get(beginIndex++)+""); for(int k=0;k<spacing;k++){ //打印元素之间的空格 System.out.print(" "); } if(beginIndex == len){ //已打印到最后一个元素 break; } } System.out.println(); } System.out.println(); } }
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以后再弄二叉树就可以简单的造例子了。