Add solutions to Codechef, HackerRank, Codeforces, ProjectEuler, HackerEarth

[satyajitghana]

Add solutions to Codechef, HackerRank, Codeforces, ProjectEuler, HackerEarth with proper Question Names in the respective folders.

NOTE : * Refrain from adding solutions to ongoing contests *

[ndkerby]

Added project euler folder with first problem: #35

[AparnaJuhi]

@satyajitghana Added Project_Euler_6 #Sum Square Review. Kindly review my PR

[zahinekbal]

Can I work on this issues ?
I want to contribute on this issues

[zahinekbal]

@satyajitghana Can I work on this issues ?
I want to contribute on this issues...
Please tell me I want to solve Hackerearth problems.

[satyajitghana]

yeah sure go ahead @zahinekbal

[AparnaJuhi]

@satyajitghana I have added Project Euler_5 cpp code #Smallest Multiple, Please review my PR.

[zahinekbal]

@satyajitghana I have added FindingMissingNumbers .C & FindingMissingNumbers.C++ and assign it in C , C++ folder respectively inside Hackerearth Folder .....
please check my Code and review my PR.....
and merge it....

[zahinekbal]

@satyajitghana I added Kadane's Algorithm for maximum-subarray-sum in c++ in Hackerrank folder...
kindly go through the code and review my PR

[legitbeep]

Added May challenge problems into a single folder since I wanted to add october challenge solutions too!

[zahinekbal]

@satyajitghana I fixed my code & added hackerearth/C/FindingMissingNumber.c ....
Please check my code and review my PR...

[uabua]

Hello. I added sql folder in hackerrank and advanced join solutions within. ⭐