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Amazon Interview Question for SDE-2s


Team: AWS
Country: United States



Comment hidden because of low score. Click to expand.
2
of 2 vote

package careercup.cardapp;

/**
 * Created by Dhatchana Moorthy.
 * Date: Aug 19, 2016
 * Time: 9:46:51 AM
 */
public class Card {
    //0 for spade, 1 for heart, 2 for diamond and 3 for club
    int cardsymbol;
    int cardnumber;

    public Card(int cardsymbol, int cardnumber)
    {
        this.cardsymbol = cardsymbol;
        this.cardnumber = cardnumber;
    }
}

package careercup.cardapp;

import java.util.Stack;
import java.util.Random;

/**
 * Created by Dhatchana Moorthy.
 * Date: Aug 19, 2016
 * Time: 9:49:50 AM
 */
public class Deck {
    Stack<Card> cardstack = new Stack<Card>();

    private static Random rand = new Random();

    public Deck()
    {
        populateDeckWithCards();
        shuffle();
    }

    public void populateDeckWithCards()
    {
        for(int i=0; i < 4; i++)
        {
            for(int j=1; j < 14; j++)
            {
                cardstack.push(new Card(i, j));
            }
        }
    }

    public void shuffle()
    {
        //fisher yates shuffle algorithm
        for(int i=cardstack.size()-1; i > 0; i--)
        {
            int swapindex = rand.nextInt(i);
            
            Card temp = cardstack.get(i);
            cardstack.set(i, cardstack.get(swapindex));
            cardstack.set(swapindex, temp);
        }
    }

    public void deal(String dealtype, int numberofpersons)
    {
        //Seperate dealtype classes can be created
        if(dealtype.equals("ace"))
        {
            int i=1;
            while(!cardstack.isEmpty())
            {
                //Seperate person classes can be created
                Card card = cardstack.pop();

                System.out.println();
                int person = i%numberofpersons;
                if(person == 0)
                {
                    person = 4;
                }

                System.out.print("Person: "+person+" cardsymbol: ");
                if(card.cardsymbol == 0)
                {
                    System.out.print("Spade");
                }
                else if(card.cardsymbol == 1)
                {
                    System.out.print("heart");
                }
                else if(card.cardsymbol == 2)
                {
                    System.out.print("diamond");
                }
                else
                {
                    System.out.print("club");
                }

                if(card.cardnumber == 1)
                {
                    System.out.print(" cardnumber: ace");
                }
                else if(card.cardnumber == 11)
                {
                    System.out.print("cardnumber: Jack");
                }
                else if(card.cardnumber == 12)
                {
                    System.out.print("cardnumber: Queen");
                }
                else if(card.cardnumber == 13)
                {
                    System.out.print("cardnumber: King");                    
                }
                else
                {
                    System.out.print("cardnumber: "+card.cardnumber);
                }

                i++;
            }
        }
    }
}

package careercup.cardapp;

/**
 * Created by Dhatchana Moorthy.
 * Date: Aug 21, 2016
 * Time: 6:45:21 PM
 */
public class CardGame {

    public static void main(String[] args)
    {
        Deck deck = new Deck();

        deck.deal("ace", 4);
    }
}

- Dhatchana Moorthy August 21, 2016 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

Attempt at a solution. Note that there is no error checking done in this code but in an interview it would be worth pointing out where errors may occur.

// ======================================================================
// Filename: deck.cc
// Description: Deck and card classes meeting requirements.
// Created: Thu Sep  1 20:51:26 2016 (-0500)
// Last-Updated: Thu Sep  1 21:29:36 2016 (-0500)
// Author: Ivan Guerra
// ======================================================================
#include <algorithm>
#include <string>
#include <vector>

class Card {
private:
    typedef std::size_t size_type;
    std::string m_suit;
    size_type m_value;
    
public:
    Card(const std::string& suit, size_type value) : m_suit(suit), m_value(value) { }
    
    std::string get_suit() const { return m_suit; }
    size_type get_value() const { return m_value; }
    void set_suit(const std::string& suit) { m_suit = suit; }
    void set_value(size_type value) { m_value = value; }

    friend bool operator==(const Card& lhs, const Card& rhs) { return (lhs.m_suit == rhs.m_suit) && (lhs.m_value == rhs.m_value); }
};

class Deck {
private:
    typedef std::size_t size_type;
    typedef std::vector<Card> card_set;
    card_set m_cards;

public:
    Deck() { }
    Deck(const card_set& cards) : m_cards(cards) { }

    size_type n_cards() const { return m_cards.size(); }
    void shuffle() { std::random_shuffle(m_cards.begin(), m_cards.end()); }
    Card draw_top() const { return m_cards[0]; }
    Card draw_bottom() const { return m_cards.back(); }
    Card draw_random();
    void add_card(const Card& val) { m_cards.push_back(val); }
    void remove_card(const Card& val) { m_cards.erase(std::find(m_cards.begin(), m_cards.end(), val)); }
    std::vector<Deck> deal(size_type n_persons, size_type hand_size);
};

Card Deck::draw_random() {
    shuffle();
    return draw_top();
}

std::vector<Deck> Deck::deal(size_type n_persons, size_type hand_size) {
    std::vector<Deck> user_decks(n_persons);
    for (auto i = 0; i < n_persons; i++) {
	for (auto j = 0; j < hand_size; j++) {
	    Card selected_card = draw_random();
	    user_decks[i].add_card(selected_card);
	    remove_card(selected_card);
	}
    }
    return user_decks;

}

- ieg September 02, 2016 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

CardShape.java

and

package com.ankitgupta;

/**
* Created by ankitgupta on 9/9/16.
*/
public enum CardShape {
SPADE,
DIAMOND,
CLUB,
HEART;
}

and

CardNumber.java

and

package com.ankitgupta;

/**
* Created by ankitgupta on 9/9/16.
*/
public enum CardNumber {
ACE,
TWO,
THREE,
FOUR,
FIVE,
SIX,
SEVEN,
EIGHT,
NINE,
TEN,
JACK,
QUEEN,
KING;
}

and

Card.java

and

package com.ankitgupta;

/**
* Created by ankitgupta on 9/9/16.
*/
public class Card {

CardShape shape;
CardNumber number;

Card(CardShape shape,CardNumber number){
this.shape = shape;
this.number = number;
}

public CardNumber getNumber() {
return number;
}

public CardShape getShape() {
return shape;
}

public String getName(){
return number + " of " + shape;
}
}

and

Deck.java

and

package com.ankitgupta;

import java.util.Random;
import java.util.Stack;

/**
* Created by ankitgupta on 9/9/16.
*/
public class Deck {

public static Stack<Card> getNewSortedDeck(){
Stack<Card> cardDeck = new Stack<Card>();
for (CardShape shape: CardShape.values()){
for (CardNumber number: CardNumber.values()){
Card card = new Card(shape,number);
cardDeck.push(card);
}
}
return cardDeck;
}

public static Stack<Card> getShuffeledDeck(){
return getShuffeledDeck(getNewSortedDeck());
}

public static Stack<Card> getShuffeledDeck(Stack<Card> deck){
Stack<Card> cardDeck = new Stack<Card>();
int count = 0;
for (int i=deck.size();i>0;i--){
Random random = new Random();
Card randomCard = deck.remove(random.nextInt(i));
cardDeck.push(randomCard);
}
return cardDeck;
}

public static void printDeck(Stack<Card> deck){
for (int i=0 ; i<deck.size();i++) {
System.out.println("Adding Random Card No. " + (i+1) + " to the Deck : " + deck.get(i).getName());
}
}
}

and

Player.java

and

package com.ankitgupta;

import java.util.Stack;

/**
* Created by ankitgupta on 9/9/16.
*/
public class Player {

private String name;
private Stack<Card> cards;

Player (String name){
this.name = name;
this.cards = new Stack<Card>();
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Stack<Card> getCards() {
return cards;
}

public void setCards(Stack<Card> cards) {
this.cards = cards;
}

public void addCard(Card card){
this.cards.push(card);
}

public void removeCard(Card card){
this.cards.remove(card);
}

}

and

CardGame.java

and

package com.ankitgupta;

import java.security.PublicKey;
import java.util.Stack;

/**
* Created by ankitgupta on 9/9/16.
*/
public class CardGame {
private Player[] players;
private int cardsPerPlayer;
Stack<Card> stackOfCards = Deck.getShuffeledDeck();
CardGame(Player[] players){
this.players = players;
this.cardsPerPlayer=0;
}

CardGame(Player[] players, int cardsPerPlayer){
this.players = players;
this.cardsPerPlayer = cardsPerPlayer;
}

public void dealCards(){
int playerCount = players.length;
if (playerCount>0){
int cardsToDeal = cardsPerPlayer==0? stackOfCards.size() :cardsPerPlayer*playerCount;
for (int i=0;i<cardsToDeal;i++){
players[i%playerCount].addCard(stackOfCards.pop());
}
}
}
public Stack<Card> getStackOfCards(){
return stackOfCards;
}
}

and

Deal.java

and

package com.ankitgupta;

import java.util.Stack;

/**
* Created by ankitgupta on 9/9/16.
*/
public class Deal {

public static void main(String[] args) {

Player player1 = new Player("Player1");
Player player2 = new Player("Player2");
Player player3 = new Player("Player3");
Player player4 = new Player("Player4");

Player[] players = {player1,player2,player3,player4};
CardGame game = new CardGame(players);
game.dealCards();

System.out.println("Player 1 Cards : ");
Deck.printDeck(player1.getCards());

System.out.println("Player 2 Cards : ");
Deck.printDeck(player2.getCards());

System.out.println("Player 3 Cards : ");
Deck.printDeck(player3.getCards());

System.out.println("Player 4 Cards : ");
Deck.printDeck(player4.getCards());

System.out.println("Remaining Cards : ");
Deck.printDeck(game.getStackOfCards());

}
}

and

- Ankit Gupta September 09, 2016 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

CardShape.java

package com.ankitgupta;

/**
 * Created by ankitgupta on 9/9/16.
 */
public enum CardShape {
	SPADE,
	DIAMOND,
	CLUB,
	HEART;
}

CardNumber.java

package com.ankitgupta;

/**
 * Created by ankitgupta on 9/9/16.
 */
public enum CardNumber {
	ACE,
	TWO,
	THREE,
	FOUR,
	FIVE,
	SIX,
	SEVEN,
	EIGHT,
	NINE,
	TEN,
	JACK,
	QUEEN,
	KING;
}

Card.java

package com.ankitgupta;

/**
 * Created by ankitgupta on 9/9/16.
 */
public class Card {

	CardShape shape;
	CardNumber number;

	Card(CardShape shape,CardNumber number){
		this.shape = shape;
		this.number = number;
	}

	public CardNumber getNumber() {
		return number;
	}

	public CardShape getShape() {
		return shape;
	}

	public String getName(){
		return number + " of " + shape;
	}
}

Deck.java

package com.ankitgupta;

import java.util.Random;
import java.util.Stack;

/**
 * Created by ankitgupta on 9/9/16.
 */
public class Deck {

	public static Stack<Card> getNewSortedDeck(){
		Stack<Card> cardDeck = new Stack<Card>();
		for (CardShape shape: CardShape.values()){
			for (CardNumber number: CardNumber.values()){
				Card card = new Card(shape,number);
				cardDeck.push(card);
			}
		}
		return cardDeck;
	}

	public static Stack<Card> getShuffeledDeck(){
		return getShuffeledDeck(getNewSortedDeck());
	}

	public static Stack<Card> getShuffeledDeck(Stack<Card> deck){
		Stack<Card> cardDeck = new Stack<Card>();
		int count = 0;
		for (int i=deck.size();i>0;i--){
			Random random = new Random();
			Card randomCard = deck.remove(random.nextInt(i));
			cardDeck.push(randomCard);
		}
		return cardDeck;
	}

	public static void printDeck(Stack<Card> deck){
		for (int i=0 ; i<deck.size();i++) {
			System.out.println("Adding Random Card No. " + (i+1) + " to the Deck : " + deck.get(i).getName());
		}
	}
}

Player.java

package com.ankitgupta;

import java.util.Stack;

/**
 * Created by ankitgupta on 9/9/16.
 */
public class Player {

	private String name;
	private Stack<Card> cards;

	Player (String name){
		this.name = name;
		this.cards = new Stack<Card>();
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Stack<Card> getCards() {
		return cards;
	}

	public void setCards(Stack<Card> cards) {
		this.cards = cards;
	}

	public void addCard(Card card){
		this.cards.push(card);
	}
	
	public void removeCard(Card card){
		this.cards.remove(card);
	}

}

CardGame.java

package com.ankitgupta;

import java.security.PublicKey;
import java.util.Stack;

/**
 * Created by ankitgupta on 9/9/16.
 */
public class CardGame {
	private Player[] players;
	private int cardsPerPlayer;
	Stack<Card> stackOfCards = Deck.getShuffeledDeck();
	CardGame(Player[] players){
		this.players = players;
		this.cardsPerPlayer=0;
	}

	CardGame(Player[] players, int cardsPerPlayer){
		this.players = players;
		this.cardsPerPlayer = cardsPerPlayer;
	}

	public void dealCards(){
		int playerCount = players.length;
		if (playerCount>0){
			int cardsToDeal = cardsPerPlayer==0? stackOfCards.size() :cardsPerPlayer*playerCount;
			for (int i=0;i<cardsToDeal;i++){
				players[i%playerCount].addCard(stackOfCards.pop());
			}
		}
	}
	public Stack<Card> getStackOfCards(){
		return stackOfCards;
	}
}

Deal.java

package com.ankitgupta;

import java.util.Stack;

/**
 * Created by ankitgupta on 9/9/16.
 */
public class Deal {

	public static void main(String[] args) {

		Player player1 = new Player("Player1");
		Player player2 = new Player("Player2");
		Player player3 = new Player("Player3");
		Player player4 = new Player("Player4");

		Player[] players = {player1,player2,player3,player4};
		CardGame game = new CardGame(players);
		game.dealCards();

		System.out.println("Player 1 Cards : ");
		Deck.printDeck(player1.getCards());

		System.out.println("Player 2 Cards : ");
		Deck.printDeck(player2.getCards());

		System.out.println("Player 3 Cards : ");
		Deck.printDeck(player3.getCards());

		System.out.println("Player 4 Cards : ");
		Deck.printDeck(player4.getCards());

		System.out.println("Remaining Cards : ");
		Deck.printDeck(game.getStackOfCards());

	}
}

- Ankit Gupta September 09, 2016 | Flag Reply


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