LeetCode题解之Insert into a Binary Search Tree

 1 TreeNode* insertIntoBST(TreeNode* root, int val) {
 2         insert(root, val);
 3         return root;
 4     }
 5     
 6     void insert(TreeNode * & t , int val)
 7     {
 8         if (t == NULL)
 9             t = new TreeNode(val);
10         else if (val < t->val) {
11             insert(t->left, val);
12         } else if (val > t->val){
13             insert(t->right, val);
14         }else {
15             
16         }
17     }