c_cpp 插入节点在bst，BST中

Posted 2021-05-14

TreeNode* insert(TreeNode *root, TreeNode *node) {
    if(!node) return root;
    if(!root) return node;
    if(root->val == node->val) return root; // already in tree, no need to insert
    if(node->val < root->val) {
        if(root->left == NULL) root->left = node;   // gist, insert into a vacant position here
        else root->left = insert(root->left, node);
    }
    else {
        if(root->right == NULL) root->right = node; // gist, insert into a vacant position here
        else root->right = insert(root->right, node);
    }
    return root;
}