# Advantages of BST over Hash Table

Hash Table supports following operations in Θ(1) time.

1) Search

2) Insert

3) Delete

The time complexity of above operations in a self-balancing Binary Search Tree (BST) (like Red-Black Tree, AVL Tree, Splay Tree, etc) is O(Logn).

So Hash Table seems to beating BST in all common operations. When should we prefer BST over Hash Tables, what are advantages. Following are some important points in favor of BSTs.

- We can get all keys in sorted order by just doing Inorder Traversal of BST. This is not a natural operation in Hash Tables and requires extra efforts.
- Doing order statistics, finding closest lower and greater elements, doing range queries are easy to do with BSTs. Like sorting, these operations are not a natural operation with Hash Tables.
- BSTs are easy to implement compared to hashing, we can easily implement our own customized BST. To implement Hashing, we generally rely on libraries provided by programming languages.
- With Self-Balancing BSTs, all operations are guaranteed to work in O(Logn) time. But with Hashing, Θ(1) is average time and some particular operations may be costly, especially when table resizing happens.

This article is contributed by **Himanshu Gupta**. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above

Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: **DSA Self Paced**. Become industry ready at a student-friendly price.

## Recommended Posts:

- Hash Table vs STL Map
- Implementing our Own Hash Table with Separate Chaining in Java
- Implementing own Hash Table with Open Addressing Linear Probing in C++
- What are Hash Functions and How to choose a good Hash Function?
- MD5 hash in Java
- Graph representations using set and hash
- Sorting using trivial hash function
- Hash Function for String data in C#
- Sort elements by frequency | Set 4 (Efficient approach using hash)
- Overview of Data Structures | Set 2 (Binary Tree, BST, Heap and Hash)
- Direct Address Table
- K most occurring strings
- Check if frequency of each element in given array is unique or not
- Java program to print all duplicate characters in a string