# Insert node to BST

• 难度：简单

``````给出如下一棵二叉查找树，在插入节点6之后这棵二叉查找树可以是这样的：
2             2
/ \           / \
1   4   -->   1   4
/             / \
3             3   6
``````

``````能否不使用递归？
``````

## Code

``````/**
* 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) {
if (root == null) {
root = node;
return root;
}
TreeNode tmp = root;
TreeNode last = null;
while (tmp != null) {
last = tmp;
if (tmp.val > node.val) {
tmp = tmp.left;
} else {
tmp = tmp.right;
}
}
if (last != null) {
if (last.val > node.val) {
last.left = node;
} else {
last.right = node;
}
}
return root;
}
}

``````