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难度：容易
要求：
给定一棵二叉查找树和一个新的树节点，将节点插入到树中。
你需要保证该树仍然是一棵二叉查找树。
2 2
/ \ / \
1 4 --> 1 4
/ / \
3 3 6
思路：递归
/**
* 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 the binary search tree.
* @param node: insert this node into the binary search tree
* @return: The root of the new binary search tree.
*/
public TreeNode insertNode(TreeNode root, TreeNode node) {
// write your code here
if(root == null || node == null){
return node;
}
int result = node.val - root.val;
if(result < 0){
root.left = insertNode(root.left, node);
}else if(result > 0){
root.right = insertNode(root.right, node);
}
return root;
}
}
