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https://github.com/shivam010/daily-coding-problem
Solving one problem every day. Problem selection is based on the Daily Coding Problem newsletter
https://github.com/shivam010/daily-coding-problem
algorithms c-plus-plus coding coding-interviews competitive-programming daily daily-coding-problem data-structures golang interview interview-questions python tree
Last synced: 6 days ago
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Solving one problem every day. Problem selection is based on the Daily Coding Problem newsletter
- Host: GitHub
- URL: https://github.com/shivam010/daily-coding-problem
- Owner: Shivam010
- License: mit
- Created: 2020-09-05T22:19:29.000Z (about 4 years ago)
- Default Branch: master
- Last Pushed: 2022-05-25T19:40:44.000Z (over 2 years ago)
- Last Synced: 2024-06-20T11:14:30.046Z (5 months ago)
- Topics: algorithms, c-plus-plus, coding, coding-interviews, competitive-programming, daily, daily-coding-problem, data-structures, golang, interview, interview-questions, python, tree
- Language: Go
- Homepage: https://www.dailycodingproblem.com/
- Size: 604 KB
- Stars: 17
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Daily Coding Problem
====================
[](https://github.com/Shivam010/daily-coding-problem/actions?query=workflow%3AScript)
[](https://github.com/Shivam010/daily-coding-problem/actions?query=workflow%3ACron)
[](https://github.com/Shivam010/daily-coding-problem/actions?query=workflow%3AGreetings)
[](https://github.com/Shivam010/daily-coding-problem)
[](https://github.com/Shivam010/daily-coding-problem)
[](https://github.com/Shivam010/daily-coding-problem)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
[](https://github.com/Shivam010/daily-coding-problem/issues/new)
[](https://github.com/Shivam010/daily-coding-problem)
[](https://github.com/Shivam010/daily-coding-problem)
[](https://github.com/Shivam010/daily-coding-problem)
> _People find their paths in the strangest of ways._
On _`September 03, 2020`_, I found this website [Daily Coding Problem](https://www.dailycodingproblem.com/), where you can subscribe
to a newsletter and get one problem a day. I like the initiative: Solving one problem every day.
Also, after college, the daily job cycle began, which led to my breakup with competitive programming. But I wanted to start
solving problems again to keep it up, but could never begin.
So, I decided to subscribe the newsletter and to solve one problem every day.
Since then I have solved _**`#67 problems`**_.
You can find the problems and solutions in their directories: [here](https://github.com/Shivam010/daily-coding-problem).
Solutions are mainly in _**C++ and Golang**_, and some problems may
also have _**Python**_ solution too, depending on what is asked in question.
> _Checkout my blog post on my habit of solving a problem daily [here](https://medium.com/coderbyte/solving-a-problem-every-day-a6de133a9254)_
_Want to join me? or Just need to stay upto date?
**Start watching this repository or connect with me.**_
_And if you want to **review my solutions** or want to **add something**, I am open for accepting PRs, code reviews.
Anything you feel that needs correction._
**Next problem:
`#089`**
**Missed problems:
`#068`
• `#069`
• `#070`
• `#071`
• `#072`
• `#073`
• `#074`
• `#075`
• `#076`
• `#077`
• `#078`
• `#079`
• `#080`
• `#081`
• `#082`
• `#083`
• `#084`
• `#085`
• `#086`
• `#087`
• `#088`**
Some of the worthy problems I have solved are listed here...
Problem: `#010`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/010/c++/code.cpp)
[](001-050/010/go/code.go)
[](001-050/010/python/code.py)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: September 12, 2020_
This problem was asked by Apple.
Implement a _**job scheduler**_ which takes in a function f and an integer n, and
calls f after n milliseconds.
**Solution(s)**:
• [C++](001-050/010/c++/code.cpp)
• [Golang](001-050/010/go/code.go)
• [Python](001-050/010/python/code.py)
Problem: `#052`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](051-100/052/c++/code.cpp)
[](051-100/052/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 24, 2020_
This problem was asked by Google.
Implement an _**LRU (Least Recently Used) caching**_ system. It should be able to be
initialized with a cache size `n`, and contain the following methods:
`set(key, value)`: sets key to value. If there are already n items in the cache
and we are adding a new item, then it should also remove the least recently used
item.
`get(key)`: gets the value at key. If no such key exists, return null. Each
operation should run in `O(1)` time.
**Solution(s)**:
• [C++](051-100/052/c++/code.cpp)
• [Golang](051-100/052/go/code.go)
Problem: `#067`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](051-100/067/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: November 08, 2020_
This problem was asked by Google.
Implement an _**LFU (Least Frequently Used) caching**_ system. It should be able to be
initialized with a cache size `n`, and contain the following methods:
`set(key, value)`: sets key to value. If there are already n items in the cache
and we are adding a new item, then it should also remove the least frequently used
item. If there is a tie, then the least recently used key should be removed.
`get(key)`: gets the value at key. If no such key exists, return null. Each
operation should run in `O(1)` time.
**Solution(s)**:
• [Golang](051-100/067/go/code.go)
Problem: `#011`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/011/c++/code.cpp)
[](001-050/011/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: September 13, 2020_
This problem was asked by Twitter.
Implement an _**autocomplete system**_. That is, given a query string s and a set of
all possible query strings, return all strings in the set that have s as a
prefix.
For example, given the query string `de` and the set of strings `[dog, deer,
deal]`, return `[deer, deal]`.
Hint: Try preprocessing the dictionary into a more efficient data structure to
speed up queries.
**Solution(s)**:
• [C++](001-050/011/c++/code.cpp)
• [Golang](001-050/011/go/code.go)
Problem: `#059`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](051-100/059/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 31, 2020_
This problem was asked by Google.
Implement a file syncing algorithm for two computers over a low-bandwidth network. What if we know the files in the two
computers are mostly the same?
**Solution(s)**:
• [Golang](051-100/059/go/code.go)
Problem: `#015`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/015/c++/code.cpp)
[](001-050/015/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: September 17, 2020_
This problem was asked by Facebook.
Given a stream of elements too large to store in memory, pick a random element
from the stream with uniform probability.
i.e. _**UniformSelection**_
**Solution(s)**:
• [C++](001-050/015/c++/code.cpp)
• [Golang](001-050/015/go/code.go)
Problem: `#055`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](051-100/055/c++/code.cpp)
[](051-100/055/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 27, 2020_
This problem was asked by Microsoft.
Implement a URL shortener with the following methods:
- `shorten(url)`, which shortens the url into a six-character alphanumeric
string, such as `zLg6wl`.
- `restore(short)`, which expands the shortened string into the original url. If
no such shortened string exists, return null.
Hint: What if we enter the same URL twice?
**Solution(s)**:
• [C++](051-100/055/c++/code.cpp)
• [Golang](051-100/055/go/code.go)
Problem: `#024`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/024/c++/code.cpp)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: September 26, 2020_
This problem was asked by Google.
Implement locking in a binary tree. A binary tree node can be locked or unlocked
only if all of its descendants or ancestors are not locked.
Design a binary tree node class with the following methods:
- `is_locked`, which returns whether the node is locked.
- `lock`, which attempts to lock the node. If it cannot be locked, then it
should return false. Otherwise, it should lock it and return true.
- `unlock`, which unlocks the node. If it cannot be unlocked, then it should
return false. Otherwise, it should unlock it and return true.
You may augment the node to add parent pointers or any other property you would
like. You may assume the class is used in a single-threaded program, so there is
no need for actual locks or mutexes. Each method should run in `O(h)`, where `h`
is the height of the tree.
**Solution(s)**:
• [C++](001-050/024/c++/code.cpp)
Problem: `#045`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/045/c++/code.cpp)
[](001-050/045/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 17, 2020_
This problem was asked by Two Sigma.
Using a function `rand5()` that returns an integer from `1 to 5 (inclusive)`
with uniform probability, implement a function `rand7()` that returns an integer
from `1 to 7 (inclusive)`.
**Solution(s)**:
• [C++](001-050/045/c++/code.cpp)
• [Golang](001-050/045/go/code.go)
Problem: `#022`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/022/c++/code.cpp)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: September 24, 2020_
This problem was asked by Microsoft.
Given a dictionary of words and a string made up of those words (no spaces),
return the original sentence in a list. If there is more than one possible
reconstruction, return any of them. If there is no possible reconstruction, then
return null.
For example, given the set of words `'quick', 'brown', 'the', 'fox'`, and the
string `"thequickbrownfox"`, you should return `['the', 'quick', 'brown', 'fox']`.
Given the set of words `'bed', 'bath', 'bedbath', 'and', 'beyond'`, and the string
`"bedbathandbeyond"`, return either `['bed', 'bath', 'and', 'beyond]` or `['bedbath',
'and', 'beyond']`
**Solution(s)**:
• [C++](001-050/022/c++/code.cpp)
Problem: `#039`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](001-050/039/c++/code.cpp)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 11, 2020_
This problem was asked by Dropbox _(System Design)_.
_**Conway's Game of Life**_ takes place on an infinite two-dimensional board of square
cells. Each cell is either dead or alive, and at each tick, the following rules
apply:
Any live cell with less than two live neighbours dies.
Any live cell with two or three live neighbours remains living.
Any live cell with more than three live neighbours dies.
Any dead cell with exactly three live neighbours becomes a live cell.
A cell neighbours another cell if it is horizontally, vertically, or diagonally
adjacent.
Implement Conway's Game of Life. It should be able to be initialized with a
starting list of live cell coordinates and the number of steps it should run
for. Once initialized, it should print out the board state at each step. Since
it's an infinite board, print out only the relevant coordinates, i.e. from the
top-leftmost live cell to bottom-rightmost live cell.
You can represent a live cell with an asterisk `(*)` and a dead cell with a dot
`(.)`.
**Solution(s)**:
• [C++](001-050/039/c++/code.cpp)
Problem: `#056`
------------
[](https://github.com/Shivam010/daily-coding-problem/issues)
[](051-100/056/go/code.go)
[](https://github.com/Shivam010/daily-coding-problem/blob/master/LICENSE)
_Date: October 28, 2020_
This problem was asked by Google.
Given an undirected graph represented as an adjacency matrix and an integer `k`,
write a function to determine whether each vertex in the graph can be colored
such that no two adjacent vertices share the same color using at most k colors.
**Solution(s)**:
• [Golang](051-100/056/go/code.go)
[]()
-----
People find their paths in the strangest of ways. Let's find our own!
Let's connect here.