Hash tables are extremely useful data structure as lookups take expected O(1) time on average, i.e. the amount of work that a hash table does to perform a lookup is at most some constant. Several data structure and algorithms problems can be very efficiently solved using hashing which otherwise have high time complexity. In this post, we will list out few problems that can be solved in elegant fashion using hashing, with significant economy of time and space.

We recommend to have basic understanding of how std::unordered_set/HashSet and std::unordered_map/HashMap works in C++/Java before moving to below Hashing Problems.

**Thank you for being with us. 🙂**

## Leave a Reply

nice collection. I love solving problem with the help of hashing..