An Interesting Math + Data Structure Problem from Codeforces (Round #430)

Hi guys! ✋

rachit jain blog, Rachit Jain, rachit jain iit roorkee, rachit jain iitr, rachit iitr,rachit codechef, rachit hackerrank, rachit jain microsoft

This is a data structure(TRIE) + math based problem from Codeforces Round #430.
Problem Link is here.   
You are given an array $A$ of size $N$, and you have to perform $M$ operations on it.  
In each operation, you are given an integer $x$, and you perform XOR operation of every element of the array with $x$. Note that the array is updated after every operation and subsequent operations are performed on modified array. At end of every operation, you need to print the mex value of the updated array.     

NOTE: mex of a set $A$ is the least whole number ( $\ge 0$ ) which is not present in $A$.    

Check out the following video where I've described the solution:
CodeForces Round 430 - Problem D Tutorial (Number Theory, Trie)

Refer the Video Description to find the links to source code and problem link.

If you liked my efforts, please hit the like button 👍, subscribe and share the videos among your college :D  

Have a good day! 😆

An Interesting Number Theory Problem from CSAcademy(Round #43)

Hi guys! ✋

rachit jain blog, Rachit Jain, rachit jain iit roorkee, rachit jain iitr, rachit iitr,rachit codechef, rachit hackerrank, rachit jain microsoft

This is a greedy, math problem from CSAcademy Round #43.
You are given two integers $N,K$ and you are required to print an array of $N$ distinct integers $<10^6$ such that there are exactly $K$ pairs $(a[i], a[j])$ with their gcd as $1$.  

Check out the following video where I've described the solution:
CSAcademy Round 43 - Coprime Pairs Tutorial (Number Theory)

Refer the Video Description to find the links to source code and problem link.

The family 💓 has grown to 600+ subscribers and I thank you guys for the love and support :)  

If you liked my efforts, please hit the like button 👍, subscribe and share the videos among your college :D  

Have a good day! 😆

YouTube Playlist for Dynamic Programming

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rachit jain blog, Rachit Jain, rachit jain iit roorkee, rachit jain iitr, rachit iitr,rachit codechef, rachit hackerrank, rachit jain microsoft

I am happy to launch the YouTube playlist for Dynamic Programming: From Zero to Hero.    

I've put in a lot of my efforts this time, kept the video detailed so that a lot of people (beginners for sure) are able to understand:
1. How to approach problems based on Dynamic Programming?
2. How to think of DP states?
3. How to build the DP recurrence relations?
4. Can DP problem be solved faster using MATRIX EXPONENTIATION? ✌

Beginners will surely learn a lot, lot, lot from this. 

Check out the following videos:
1. Intro to DP: How to approach DP states, Recurrences 
2. Dynamic Programming + Matrix Exponentiation

Check the Video Description to find the links to source code and problem link.

Finally, the family 💓 has grown to 500+ subscribers and I thank you guys for the love and support :)  

If you liked my efforts, please hit the like button 👍, subscribe and share the videos among your college :D  

Have a good day! 😆

Video Tutorial For a SquareRoot Decomposition Problem - HILLJUMPING

rachit jain blog, Rachit Jain, rachit jain iit roorkee, rachit jain iitr, rachit iitr,rachit codechef, rachit hackerrank, rachit jain microsoft

Hi

I've put in a lot of my efforts this time, kept the video detailed so that a lot of people including beginners are able to understand how to solve this tough squareroot decomposition problem HILLJUMPING from Codechef August 17 Long Challenge.

You can learn about SquareRoot Decomposition, binary search, and how a simple and beautiful solution is built up, starting from scratch :D

Beginners will surely learn a lot, lot, lot from this. 

Check out the video editorial here.
Check the Video Description to find the links to source code and problem link.

If you do not want the problem description, skip to 3:25
Then I explain my approach till 14:50 after which code discussion begins.

Also, YouTube decreased the volume level after upload. So please use headfones, and if any of you
has a solution to this, let me know!

My YouTube Channel for Competitive Programming

rachit jain blog, Rachit Jain, rachit jain iit roorkee, rachit jain iitr, rachit iitr,rachit codechef, rachit hackerrank, rachit jain microsoft

My very own YouTube Channel

Tags: video-tutorials,YouTube,data-structures, algorithms

Hi everybody,

I've finally launched my very own YouTube Channel here.

Its a kind request to LIKE the video if it helped you. 
This is important for me as more likes builds a trust for future viewers :)

At present, I plan to upload my video screencasts of online contests and video tutorials of some interesting programming problems that I encounter during daily online contests.

The pattern each video follows is:  
1. Problem Description  
2. Explanation/Solution  
3. Code Implementation/Discussion      

As a beginner, I was a bit slow while talking and I request all of you to watch the videos at 1.25x or 1.5x speed for better experience.

To begin off, I've covered some problems from the [Codechef August Long Challenge](https://www.codechef.com/AUG17).

1. [Palindromic Game] (Analysis based, medium)  
=> Video Link 

2. [Chef and Fibonacci Array] (Medium DP)
=> Video Link 

3. [Strings and Graphs] (Interesting analysis, medium-hard)  
=> Video Link

Video for Hill Jumping will be coming soon :)  
EDIT: Here is the video editorial for Hill Jumping.

Why should you subscribe to this channel:
1. You couldn't solve problems I make videos about: majorly covers beginners and intermediate level coders.    
2. You face difficulty in understanding the text editorial.  
3. You enjoy solving difficult yet interesting problems.
4. You really wanted some YouTube channel that talks about problems based on data structures and algorithms, and discuss how they can be solved.  

I hope this will help many people. Please subscribe and like the videos if you found them helpful.
Comment if you face any difficulties or if you have any recommendations for me.

With my common sense and your feedback, I hope the future videos will be of much greater quality :)  

Have a good day!