题解 | #重建二叉树#

递归，参考：
/**

• Definition for binary tree

• public class TreeNode {

• int val;

• TreeNode left;

• TreeNode right;

• TreeNode(int x) { val = x; }

• }

• /
  import java.util.Arrays;
  public class Solution {
  public TreeNode reConstructBinaryTree(int [] pre,int [] vin) {

    if(pre.length==0||vin.length==0) return null;
    TreeNode root = new TreeNode(pre[0]);
    for(int i=0 ;i<pre.length;i++){
        if(vin[i] == pre[0]){
        root.left = reConstructBinaryTree(Arrays.copyOfRange(pre,1,i+1),
                              Arrays.copyOfRange(vin,0,i));
        root.right = reConstructBinaryTree(Arrays.copyOfRange(pre,i+1,pre.length),
                                          Arrays.copyOfRange(vin,i+1,vin.length));
       break;
    }
  }
    return root;

  }
  }