Splitwise

FR

1.User can create a group and add/remove participants
1.user can add a expenses between partiticants in a group or individual participant
2.user can split the amount based on split type selected so can be different types of split logic
3.on adding expenses , system compute all participants owe amount and update the balance between pair
4.Users can settle up — record a payment between two users, which updates their balance accordingly.

5.Users can view their net balance with a specific user, or a summary of all balances across users.
6.valided the split amount should be equal to the total

NFR

1.consistency : addition of expenses, should reflect for all the participants or neither
2.Concurrency : safely handle expenses addition and settlements that touch overlapping user
3.Extensible: system should be able to add new split logic
4.Scalable: support group of user , groups and expenses

Entities

User
-

I am preparing for Deshaw interview , which is in 8 days

The interview will focus on:

- Problem solving (data structures & algorithms)

- Programming language fundamentals

- Core CS fundamentals

for the Senior Member, Tech (All positions) role and i use java as my coding lanague

and honestly i am very week in Programming language fundamentals and core CS fundamentals

so provide me a proper plan for preparing these two like topic and where to study

and also provide me all the previously asked questions

and for Problem solving (data structures & algorithms) provide me all the previously asked questions

and topic wise revision questions

and go deeper to verify and check all concepts or questions asked in deshaw

provide me in a proper excel to track what what i have done

LinkedHashMap why need this in reposiroy

Leetcode Hackathon

Difficult : SMALL, HARD, MEDIUM

Problem
-problemId : String
-description : String
-score : int

-tags : Set<String>
-difficulty: DIFFICULTY

Contestant

-id : String
-name :String

-department: String

Submission
-contestantID : String

-problemId: String

-timeTakenSeconds: int

-solvedAt : Instant

-scoreAwarded : int

ContestantRepository interface
InMemoryContestantRepository - implement ContestantRepository
+save(contestant)

+getContestant(id)
+findAll()

InMemoryProblemRepository
+save(problem)
+findByID(problemID)
+findAll()

InMemorySubmissionRepository
+save(submission)
+findByContestantId(contestantId)
+findByProblemId(problemID)
+findAll()

ContestantService
-contestantRepository

-problemRepository

-submissionRepository

+addContestant(string name , String desc)
+fetchSolvedProblems(contestantID) : List<Problems>

ProblemService
-problemRepository

-submissionRepository
+addProblem()
+fetchProblemsOnFilter(filters, sort)
+getTopNProblems(tag, n)
+getProblemStrats(problemID) : ProblemStrats

ProblemStrats

-solveCount
-averageTimeTakeSeconds

SolveResult
-scoreAwarded: int

-recommendatedProblems : List<Problem>

ScoringStrategy interface
TimeAdjustedScoreStrategy - implement ScoringStrategy

+calculateScore(problem , timeTaken)

RecommendationStrategy interface

SimilarTagRecommendationStrategy - implement RecommendationStrategy

+recommended(problem , list<Problem> candidate, count) : List<Problem>

ContestService

-scoringStrategy
-submissionRepository

-contestantRepositiory

-problemRepository

+solve(contestantID, problemID, timeTaken) : SolveResult

Calc score awarded - using scoring strategy
Save submission

get recommended problems using recommendationStrategy
Create SolveResult

+getLeader()

Fetch from submssionrepo