Deicide:
The almighty Rust

Seemed like pascal..

Temmylee01:
What language is this

This should be Golang

Why do I feel you could get all the keys into an array and get random key, then use that to access your map? I understand it would add additional iteration, which you already made up for in the remove function.

I think you are overthinking it bro. I believe what the interviewer is testing here is how to deal with real life problem like this. HashMap would be fine. You can create a class Lottery and explain to them that a user have to have a unique ID. So store data of the class, such as id, name, and others. That way you can use random module to pick a random id number in the range of the id and get name from the hashmap of users using the randomly picked id. I think this will be enough.

To do extra, you can think OOP. Create two class, one for lottery and Person. So the Lottery class will inherit from person methods add, and remove user. You can then put only the random method in Lottery. I wouldn't code this in interview but just explain to them that if we have a bigger system, this is help in scaling and code maintenance.

Deicide:
Too much pressure that i couldn't even think straight. The question is not even that hard simple data structure question that i can't even believe i bombed it. Chai.

I was asked to implement a Lottery system. that has the following functionality.

1. add_user(string: user)
2. remove_user(string: user)
3. pick_random_winner() -> string

Yes that was how easy it was but i bombed. Immediately i saw add and remove my mind immediately went to the king of all data structure HashMap but boy i was wrong a vector would do just fine, the problem here is the functionality to pick_random_user and the function signature. how do you do that with a HashMap if data are stored anywhere in memory? meanwhile in Array everything stored contiguously. But i was busy thinking of speed

In as much as hash map would be good for add and removal in 0(1) time. it's bad for random access.

could use HashSet but random would still Bleep you up.

My bad implementation.

struct Lottery {
     map: HashMap<i32, String>,
}

impl Lottery {
    // first problem realized here, what would be the key? and i don already talk say na hash map go good for this things o chai  

    fn add_user(&mut self, string: user){
         // But this would not work it doesn't work that way. it would have made sense if the function has a signature for key.
         self.map.insert(user); error, where is the key ?  
     }

    fn remove_user(&mut self, string: user){
         //no key can't remove anything 
     }

    fn pick_random_user(&self){
         // impossible!!! no key no random - even if there was a key it doesn't  reorder it self unlike Vector. This might be possible in language like python  
     }
}

Now for a better implementation, that only came to my head as i was not overthinking immediately after the interview.

struct Lottery {
     user: Vec<String>,
}

impl Lottery {
    fn add_user(&mut self, string: user){
         // we just insert
         self.user.push(user); 
     }

    fn remove_user(&mut self, string: user){
         // linear search and then remove
        if self.participant.contains(&participant) {
            self.participant.retain(|x| x != &participant);
        }
     }

    fn pick_random_user(&self){
         let random_gen = // algorithm that generate random number
         let random = random_gen % self.user.len();
         self.user[random]
     }
}

Anyways we move!!. Best advice? CALM DOWN! Technical interview are fun but trust 9ja network to Bleep you up.

I will still use my hashmap but use interger as the key... that value will be helpful when select a random

Thanks.... but how am I supposed to understand this

satandeterrible:
Shame on you.

Chef why na na?

All he typed there seems like abracadabra to this ancestor

That is my thought too. HashMap inform of JSON is widely use in the industry for user informations and other. They deal with Api a lot of time and most of the time JSON object is returned in form of HashMap. Even in big companies like Google and others.

Harnny:
I will still use my hashmap but use interger as the key... that value will be helpful when select a random

Deicide:
Too much pressure that i couldn't even think straight. The question is not even that hard simple data structure question that i can't even believe i bombed it. Chai.

I was asked to implement a Lottery system. that has the following functionality.

1. add_user(string: user)
2. remove_user(string: user)
3. pick_random_winner() -> string

Yes that was how easy it was but i bombed. Immediately i saw add and remove my mind immediately went to the king of all data structure HashMap but boy i was wrong a vector would do just fine, the problem here is the functionality to pick_random_user and the function signature. how do you do that with a HashMap if data are stored anywhere in memory? meanwhile in Array everything stored contiguously. But i was busy thinking of speed

In as much as hash map would be good for add and removal in 0(1) time. it's bad for random access.

could use HashSet but random would still Bleep you up.

My bad implementation.

struct Lottery {
     map: HashMap<i32, String>,
}

impl Lottery {
    // first problem realized here, what would be the key? and i don already talk say na hash map go good for this things o chai  

    fn add_user(&mut self, string: user){
         // But this would not work it doesn't work that way. it would have made sense if the function has a signature for key.
         self.map.insert(user); error, where is the key ?  
     }

    fn remove_user(&mut self, string: user){
         //no key can't remove anything 
     }

    fn pick_random_user(&self){
         // impossible!!! no key no random - even if there was a key it doesn't  reorder it self unlike Vector. This might be possible in language like python  
     }
}

Now for a better implementation, that only came to my head as i was not overthinking immediately after the interview.

struct Lottery {
     user: Vec<String>,
}

impl Lottery {
    fn add_user(&mut self, string: user){
         // we just insert
         self.user.push(user); 
     }

    fn remove_user(&mut self, string: user){
         // linear search and then remove
        if self.participant.contains(&participant) {
            self.participant.retain(|x| x != &participant);
        }
     }

    fn pick_random_user(&self){
         let random_gen = // algorithm that generate random number
         let random = random_gen % self.user.len();
         self.user[random] 
     }
}

Anyways we move!!. Best advice? CALM DOWN! Technical interview are fun but trust 9ja network to Bleep you up.

What language is this, also which book can you recommend to learn DSA.

Hmm, how would this benefit you? Remember that what goes around comes around too.
[quote author=Meadew post=121162105][/quote]

Ulunne777:
Let us pretend we understand.
Goodluck

It's for the initiated.

Initiated into programming.

If I was to implement a lottery with that functionality, I would have used a linked list...

Op which language are you coding in?
Because I'm sure that exercise would be a cakewalk if implemented in python.
Meanwhile your codes don override flexwrap for nairaland

I was one of the best Java and C# programmers in Aptech back in 2003 to 2006, 1yr not practicing I forgot it all,I had to change to hardware and networking,cctv and biometrics installation. Programming needs constant practice.

I dont understand the language you are using but I am not bothered about that.

What you considered a better implementation was lacking interface. You are not building a loosely coupled application this way. Where is that contract in your implementation?

li2pac1717:
I think you are overthinking it bro. I believe what the interviewer is testing here is how to deal with real life problem like this. HashMap would be fine. You can create a class Lottery and explain to them that a user have to have a unique ID. So store data of the class, such as id, name, and others. That way you can use random module to pick a random id number in the range of the id and get name from the hashmap of users using the randomly picked id. I think this will be enough.

I actually explained this to them.

Please look for this logo on your ballot papers — that is Labour Party (LP)!
Incase you don't see "LP" written on it, don't worry.

Just vote for Peter Obi

Nigeria must move forward by fire by force !!!

Harnny:
I will still use my hashmap but use interger as the key... that value will be helpful when select a random

except the language support auto generated int for value this solution wouldn't work.

MT:
I dont understand the language you are using but I am not bothered about that.

What you considered a better implementation was lacking interface. You are not building a loosely coupled application this way. Where is that contract in your implementation?

What do you mean.

They already gave me the structure of the code. All I just had to do was fill it up. So the functions they gave me I couldn't change it to add more parameters.

ThrustReverser:
Op which language are you coding in?
Because I'm sure that exercise would be a cakewalk if implemented in python.
Meanwhile your codes don override flexwrap for nairaland

I didn't use python cause I am not conversant with oop in python.

Deicide:
except the language support auto generated int for value this solution wouldn't work.

It's interview , simply create a variable to hold the size of your dictionary as you add. Also, in interview, you are allowed to explain the draw back of your implementations and what you will do in ideal situation.

satandeterrible:
Shame on you.

Someone like you don't deserve the truth or relate anything serious to.

You have a judgemental mindset.

Deicide:
I didn't use python cause I am not conversant with oop in python.

For me, OOP is sweetest in python.
It is such a fluid language to code in

Harnny:

It's interview , simply create a variable to hold the size of your dictionary as you add. Also, in interview, you are allowed to explain the draw back of your implementations and what you will do in ideal situation.

I was given a prototype.

Technical interviews are tough. Don't beat yourself up, there's always another one.

Deicide:
The almighty Rust

What is almighty about Rust. All languages has its uniqueness and technicality. So no is easy just in case you have that assumption.

Deicide:
Too much pressure that i couldn't even think straight. The question is not even that hard simple data structure question that i can't even believe i bombed it. Chai.

I was asked to implement a Lottery system. that has the following functionality.

1. add_user(string: user)
2. remove_user(string: user)
3. pick_random_winner() -> string

Yes that was how easy it was but i bombed. Immediately i saw add and remove my mind immediately went to the king of all data structure HashMap but boy i was wrong a vector would do just fine, the problem here is the functionality to pick_random_user and the function signature. how do you do that with a HashMap if data are stored anywhere in memory? meanwhile in Array everything stored contiguously. But i was busy thinking of speed

In as much as hash map would be good for add and removal in 0(1) time. it's bad for random access.

could use HashSet but random would still Bleep you up.

My bad implementation.

struct Lottery {
     map: HashMap<i32, String>,
}

impl Lottery {
    // first problem realized here, what would be the key? and i don already talk say na hash map go good for this things o chai  

    fn add_user(&mut self, string: user){
         // But this would not work it doesn't work that way. it would have made sense if the function has a signature for key.
         self.map.insert(user); error, where is the key ?  
     }

    fn remove_user(&mut self, string: user){
         //no key can't remove anything 
     }

    fn pick_random_user(&self){
         // impossible!!! no key no random - even if there was a key it doesn't  reorder it self unlike Vector. This might be possible in language like python  
     }
}

Now for a better implementation, that only came to my head as i was not overthinking immediately after the interview.

struct Lottery {
     user: Vec<String>,
}

impl Lottery {
    fn add_user(&mut self, string: user){
         // we just insert
         self.user.push(user); 
     }

    fn remove_user(&mut self, string: user){
         // linear search and then remove
        if self.participant.contains(&participant) {
            self.participant.retain(|x| x != &participant);
        }
     }

    fn pick_random_user(&self){
         let random_gen = // algorithm that generate random number
         let random = random_gen % self.user.len();
         self.user[random]
     }
}

Anyways we move!!. Best advice? CALM DOWN! Technical interview are fun but trust 9ja network to Bleep you up.

what lang is this

Ishilove:

Kuku kee person. Mscheeeeeew

looool Oga no be only u o, me wey be IT person I no even know wetin be dat...

Meadew:
Beloved, can any kind hearted person please assist me with little money to get drugs. Am seriously down with malaria and typhoid, and I don't have a dime on me to eat or buy medicine am running temperature please.cant die in silence please help me in any little way. May God meet you at the point of your needs, amen.
Please my name is angela oyom

067801

6041
G.TBank

Nobody should give this scammer any money

9jatriot:
Send them an email with your new solution, you never can tell.

Just tell them that you came up with a much simpler solution after you got off the interview. Nothing to lose here

If they do not have anyone better than you within that interview itself, rather than conduct a new one, they may call you again

OP, please take this advice.