Cattle off network reconstruction java binary tree

topic:

And enter the result in a preorder traversal of a binary tree in preorder traversal of the binary tree a rebuild. Suppose Results preorder traversal order and input of duplicate numbers are free. Before entering e.g. preorder traversal sequence {1,2,4,7,3,5,6,8} and {4,7,2,1,5,3,8,6} order traversal sequence, and the reconstructed binary tree return.

Problem solving:

链接：https://www.nowcoder.com/questionTerminal/8a19cbe657394eeaac2f6ea9b0f6fcf6?answerType=1&f=discussion
来源：牛客网

/**
 * 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 [] in) {
        if (pre.length == 0 || in.length == 0) {
            return null;
        }
        The root the TreeNode ; = new new the TreeNode (pre [0 ]);
         // find the roots in the preamble in order 
        for ( int I = 0; I <in.length; I ++ ) {
             IF (in [I] == pre [0 ]) {
                 // left subtree, attention copyOfRange functions, left and right to open and close 
                root.left = reConstructBinaryTree (Arrays.copyOfRange (pre,. 1, I +. 1), Arrays.copyOfRange (in, 0 , I));
                 // right subtree, attention copyOfRange functions, left and right to open and close 
                root.right = reConstructBinaryTree (Arrays.copyOfRange (pre, I +. 1, pre.length), Arrays.copyOfRange (in, I +. 1 , in.length));
                 BREAK 
            }
        }
        return root;
    }
}