重建二叉树

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输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。假设输入的前序遍历和中序遍历的结果中都不含重复的数字。例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回

import java.lang.reflect.Array;import java.util.ArrayList;public class NiuKe4 {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub    int pre[]=new int[]{1,2,3,4};    int in[]=new int[]{4,3,2,1};    NiuKe4 test=new NiuKe4();    TreeNode treeNode=test.reConstructBinaryTree(pre, in);    System.out.println(treeNode.right.val);} public TreeNode reConstructBinaryTree(int [] pre,int [] in) {        return ConBTree(pre,0,pre.length-1,in,0,in.length-1);    }    public TreeNode ConBTree(int [] pre,int preleft,int preright,int [] in,int inleft,int inright){        if(preleft > preright || inleft> inright)//当到达边界条件时候返回null            return null;        //新建一个TreeNode        TreeNode root = new TreeNode(pre[preleft]);        //对中序数组进行输入边界的遍历        for(int i = inleft; i<= inright; i++){            if(pre[preleft] == in[i]){                //重构左子树，注意边界条件                root.left = ConBTree(pre,preleft+1,preleft+i-inleft,in,inleft,i-1);                //重构右子树，注意边界条件                root.right = ConBTree(pre,preleft+i+1-inleft,preright,in,i+1,inright);            }        }        return root;         }}

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