Question

Please provide a solution to "Data Structures and Problem Solving Using Java (4th Edition)," Chapter 6, Problem 32E:

https://www.chegg.com/homework-help/maintaining-invariant-elements-priority-queue-sorted-non-inc-chapter-6-problem-32E-solution-9780133001679-exc

Answer 1

Given Question:

Please find the below answer:

package MasterSachin;
import java.util.*;
import java.util.function.Consumer;
import java.util.stream.Collectors;

/*---Multiset Class---*/
class Multiset < E > {
private List < E > values; /* List to store distinct values */
private List < Integer > frequency; /* List to store counts of distinct values */
private final String ERROR_MSG = "Count cannot be negative: ";

public Multiset() {
values = new ArrayList < > ();
frequency = new ArrayList < > ();
}
//---setCount Method---
public int setCount(E element, int count) {
if (count < 0) {
throw new IllegalArgumentException(ERROR_MSG + count);
}
if (count == 0)
remove(element);
int index = values.indexOf(element);
if (index == -1)
return add(element, count);
int prevCount = frequency.get(index);
frequency.set(index, count);
return prevCount;
}
//---Adding all method---
boolean addAll(Collection << ? extends E > c) {
for (E element: c)
add(element, 1);
return true;
}
//---Adding element to multiset count---
public int add(E element, int count) {
if (count < 0) {
throw new IllegalArgumentException(ERROR_MSG + count);
}
int index = values.indexOf(element);
int prevCount = 0;
if (index != -1) {
prevCount = frequency.get(index);
frequency.set(index, prevCount + count);
} else if (count != 0) {
values.add(element);
frequency.add(count);
}
return prevCount;
}

public boolean add(E element) {
return add(element, 1) >= 0;
}

//---checks if exists---
public boolean contains(Object element) {
return values.contains(element);
}
//---Specified number removes---
public int remove(Object element, int count) {
if (count < 0) {
throw new IllegalArgumentException(ERROR_MSG + count);
}
int index = values.indexOf(element);
if (index == -1)
return 0;
int prevCount = frequency.get(index);
if (prevCount > count) {
frequency.set(index, prevCount - count);
} else {
values.remove(index);
frequency.remove(index);
}
return prevCount;
}
//---Deleting element from multiset---
public boolean remove(Object element) {
return remove(element, 1) > 0;
}
//---Checks the elements---
public boolean containsAll(Collection << ? > c) {
return values.containsAll(c);
}
//---Adding all elements to specified array for multiset---
public void addAll(E...arr) {
for (E element: arr)
add(element, 1);
}
//---For string method---
@Override
public String toString() {
StringBuilder sb = new StringBuilder("[");
for (int i = 0; i < values.size(); i++) {
sb.append(values.get(i));
if (frequency.get(i) > 1)
sb.append(" x ").append(frequency.get(i));
if (i != values.size() - 1)
sb.append(", ");
}
return sb.append("]").toString();
}
}
public class SetUtils {
//---Implementation---
public static void main(String[] args) {
Multiset < String > multiset = new Multiset();
multiset.add("Sachin");
multiset.add("AB de Villiers", 2);
multiset.addAll("Ind", "Aus");
multiset.addAll(Arrays.asList("USA", "Pak", "Indo", "swiss"));
System.out.println(multiset);
multiset.remove("AB de Villiers");
multiset.remove("Pak", 2);
System.out.println(multiset);
multiset.setCount("Tokyo", 2);
multiset.setCount("France", 3);
multiset.setCount("Belgium", 4);
multiset.setCount("Aus", 0);
System.out.println(multiset);
}
}