Daily Coding Problem

Get Exceptionally Good at Coding Interviews

By solving one problem every day

Highest ROI investment for coders

Only accepting 48 / 500 more subscribers (we can only respond to so many solutions). We're also hiring technical writers.

This fee is fully refundable for 30 days.

How it works

Sample questions

1. A city planner wants to plan her city such that parks are close to peoples' homes. Given an N by N matrix representing the city, where each coordinate can either be a 'H' (home), 'W' (water), or 'E' (empty), place K parks, 'P', in the empty parts of the city such that they are close to peoples' homes. Specifically, minimize the sum of the Manhattan distances from peoples' homes to the nearest park. People can't swim across the water.
2. Given a stack of integers, sort it without using any additional data structures other than one extra stack.
3. An XOR linked list is a more memory efficient doubly linked list. Instead of each node holding a next, and prev fields, it holds a both which is an XOR of the next node and the previous node. Implement an XOR linked list; it has an add(element) which adds the element to the end, and a get(index) which returns the node at index.
4. A full binary tree is either a node with no children (a leaf) or a node with two children that are full binary trees. Given a pre-order traversal of a full binary tree's values, e.g. ['+', 3, '*', 2, 5], reconstruct the original tree.

Why not Leetcode or Cracking the Coding Interview?

We found full-time students and engineers are too busy to go through a gigantic list of questions. With our mailing list, you just have to attempt one question every day; consistent practice is the best way to learn. We also make sure the questions have kept up with the times and the difficulty of real interview questions.

How to pass the interview

There’s no substitute other than practice. We’ve ensured that the questions in the mailing list are at the same difficulty as questions you will get at top companies. Interviews will become a walk in the park once you get the hang of solving questions every day.

What subscribers say

"After being in the mailing list for just 3 months I was able to receive a Software Engineer offer at Facebook. I highly recommend it to people who want to put in just a few months of extra effort to pass hard interviews." - Josh D.

"I landed my job at Amazon after doing regular problems from the mailing list. I’ve taken algorithms courses and read through the Cracking the Coding Interview but I was never able to pass the interviews. They helped, but the questions weren't as hard. It also really helps that I can do one problem a day, it makes the whole process not as overwhelming." - Ken W.

What kinds of questions will you send?

We have the following areas we pick from. However, the questions will be chosen with a distribution that's more aligned with what you get in the actual interviews.

1. Linked Lists
2. Heaps
3. Trees
4. Graphs
5. Randomized Algorithms
6. Functional Algorithms
7. Dynamic Programming and Backtracking
8. Arrays
9. Stacks and Queues
10. Strings
11. Bit Manipulation
12. Object Oriented Design
13. Networking and Distributed Systems
14. Systems Design

Who are we?

Daily Coding Problem started with a group of college friends in 2014 and have grown to more than 300 coders. All of us are employed now but still enjoy solving interesting coding problems.

We're a group of hackers with experience working at Google, Twitter, Yelp and Amazon. We have a passion for algorithms and systems that are designed to scale to billions of users. We were frustrated at the resources available for preparing for interviews and wanted to solve this problem for others.

Highest ROI investment for coders

Only accepting 48 / 500 more subscribers.

We're hiring coders to give quality feedback emails and write interesting problems.

Ping us at founders@dailycodingproblem.com