【剑指offer】通过先序中序构造二叉树

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
//从根节点出发确定左右子树的节点，递归下去
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<vin.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;
    }
}