java two easy exercise

public class Activity9C { public static void main(String[] args) { String[] names = { "Zelma", "Clayton", "Casper", "Ihor", "Edwina" }; int[] severities = { 1, 2, 3, 1, 3 }; PatientList list; list = new PatientList(); testPatientList(list, names, severities, 0); System.out.println("\nEnd of processing."); } public static void testPatientList(PatientList list, String[] names, int[] severities, int pos) { PatientList copy; if (pos < names.length) { list.add(names[pos], severities[pos]); copy = list.clone(); copy.print(); System.out.println("Admitting: " + copy.nextAdmission()); System.out.println(); testPatientList(list, names, severities, pos + 1); testPatientList(copy, names, severities, pos + 1); } } } class Patient { private String name; private int arrival; private int severity; public Patient(String name, int arrival, int severity) { this.name = name; this.arrival = arrival; this.severity = severity; } public boolean isAdmittedBefore(Patient other, int lastArrival) { boolean before; int priority, otherPriority; if (severity == 3) { // admitted before, unless the other's severity is 3 and arrived earlier before = (other.severity != 3) || (other.arrival > arrival); } else if (other.severity == 3) { before = false; } else { priority = (lastArrival - arrival) * severity; otherPriority = (lastArrival - other.arrival) * other.severity; before = (priority > otherPriority) || ((priority == otherPriority) && other.arrival > arrival); } return before; } public String toString() { return name + " arrived at " + arrival + " with severity " + severity; } } class PatientList { private PatientNode head; private int lastArrival; public PatientList() { head = null; lastArrival = 0; } public void add(String name, int severity) { Patient patient; lastArrival++; patient = new Patient(name, lastArrival, severity); head = new PatientNode(patient, head); } public Patient nextAdmission() { PatientNode current; PatientNode previous; PatientNode toAdmitCurrent = null; PatientNode toAdmitPrevious = null; current = head; previous = null; while (current != null) { if (toAdmitCurrent == null) { toAdmitCurrent = current; } else { if (current.data.isAdmittedBefore(toAdmitCurrent.data, lastArrival)) { toAdmitCurrent = current; toAdmitPrevious = previous; } } previous = current; current = current.next; } if (toAdmitCurrent != null) { if (toAdmitPrevious == null) { head = toAdmitCurrent.next; } else { toAdmitPrevious.next = toAdmitCurrent.next; } return toAdmitCurrent.data; } else { return null; } } public void print() { PatientNode current; int size = 0; current = head; while (current != null) { System.out.println(current.data); size++; current = current.next; } System.out.println("Size = " + size); System.out.println("Last arrival = " + lastArrival); } public PatientList clone() { PatientList copy; PatientNode current; PatientNode copyCurrent; PatientNode newNode; copy = new PatientList(); current = head; copyCurrent = null; while (current != null) { newNode = new PatientNode(current.data, null); if (copyCurrent == null) { copy.head = newNode; } else { // last node in copy points to the new node copyCurrent.next = newNode; } // move to the next node in both lists copyCurrent = newNode; current = current.next; } copy.lastArrival = lastArrival; return copy; } } class PatientNode { public Patient data; public PatientNode next; public PatientNode(Patient data, PatientNode next) { this.data = data; this.next = next; } }