Clone Binary Tree.java

很简单的一道题目。
使用 分治 的方法即可解决。

/*
Description
For the given binary tree, return a deep copy of it.

Example
Given a binary tree:
     1
   /  \
  2    3
 / \
4   5
return the new binary tree with same structure and same value:
     1
   /  \
  2    3
 / \
4   5

Tags 
Binary Tree
*/

/**
 * Definition of TreeNode:
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left, right;
 *     public TreeNode(int val) {
 *         this.val = val;
 *         this.left = this.right = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param root: The root of binary tree
     * @return root of new tree
     */
    public TreeNode cloneTree(TreeNode root) {
        if (root == null) {
            return null;
        }
        
        TreeNode cloneRoot = new TreeNode(root.val);
        cloneRoot.left = cloneTree(root.left);
        cloneRoot.right = cloneTree(root.right);
        return cloneRoot;
    }
}