Can you help me solve this problem?

The goal of this exercise is to implement the shuffling algorithm from this chapter. 1. In the repository for this book, you should find the file named Deck.java. Check that you can compile it in your environment. 2. Implement the randomInt method. You can use the nextInt method provided by java.util.Random, which we saw in Section 7.6. Hint: To avoid creating a Random object every time randomInt is invoked, consider defning a class variable. 3. Write a swapCards method that takes two indexes and swaps the cards at the given locations. 4. Fill in the shuffle method using the algorithm in Section 13.2.

import java.util.Arrays; import java.util.Random;

/** * A deck of playing cards (of fixed length). */ public class Deck {

private Card[] cards;

/** * Constructs a standard deck of 52 cards. */ public Deck() { this.cards = new Card[52]; int index = 0; for (int suit = 0; suit <= 3; suit++) { for (int rank = 1; rank <= 13; rank++) { this.cards[index] = new Card(rank, suit); index++; } } }

/** * Constructs a deck of n cards (all null). */ public Deck(int n) { this.cards = new Card[n]; }

/** * Gets the internal cards array. */ public Card[] getCards() { return this.cards; }

/** * Displays each of the cards in the deck. */ public void print() { for (Card card : this.cards) { System.out.println(card); } }

/** * Returns a string representation of the deck. */ public String toString() { return Arrays.toString(this.cards); }

/** * Randomly permutes the array of cards. */ public void shuffle() { }

/** * Chooses a random number between low and high, including both. */ private static int randomInt(int low, int high) { return 0; }

/** * Swaps the cards at indexes i and j. */ private void swapCards(int i, int j) { }

/** * Sorts the cards (in place) using selection sort. */ public void selectionSort() { }

/** * Finds the index of the lowest card * between low and high inclusive. */ private int indexLowest(int low, int high) { return 0; }

/** * Returns a subset of the cards in the deck. */ public Deck subdeck(int low, int high) { Deck sub = new Deck(high - low + 1); for (int i = 0; i < sub.cards.length; i++) { sub.cards[i] = this.cards[low + i]; } return sub; }

/** * Combines two previously sorted subdecks. */ private static Deck merge(Deck d1, Deck d2) { return null; }

/** * Returns a sorted copy of the deck using selection sort. */ public Deck almostMergeSort() { return this; }

/** * Returns a sorted copy of the deck using merge sort. */ public Deck mergeSort() { return this; }

/** * Reorders the cards (in place) using insertion sort. */ public void insertionSort() { } }