lintcode-在二叉查找树中插入节点-85

2             2
/ \           / \
1   4   -->   1   4
/             / \
3             3   6

/**
* Definition of TreeNode:
* class TreeNode {
* public:
*     int val;
*     TreeNode *left, *right;
*     TreeNode(int val) {
*         this->val = val;
*         this->left = this->right = NULL;
*     }
* }
*/
class Solution {
public:

TreeNode* insertNode(TreeNode* root, TreeNode* node) {
if(!node)
return root;
if(!root)
return root=node;

TreeNode *cur=root;

while(cur){
if(node->val==cur->val)
return root;
else if(node->val<cur->val){
if(!cur->left){
cur->left=node;
return root;
}
cur=cur->left;
}else{
if(!cur->right){
cur->right=node;
return root;
}
cur=cur->right;
}
}
}
};