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bjrara
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‎homework/src/main/java/com/offline/training/homework/hw7/ListSorts.java

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package com.offline.training.homework.hw7;
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/* ListSorts.java */
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import com.offline.training.homework.hw7.list.*;
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public class ListSorts {
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private final static int SORTSIZE = 1000;
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/**
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* makeQueueOfQueues() makes a queue of queues, each containing one item
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* of q. Upon completion of this method, q is empty.
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* @param q is a LinkedQueue of objects.
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* @return a LinkedQueue containing LinkedQueue objects, each of which
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* contains one object from q.
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**/
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public static LinkedQueue makeQueueOfQueues(LinkedQueue q) {
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// Replace the following line with your solution.
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return null;
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}
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/**
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* mergeSortedQueues() merges two sorted queues into a third. On completion
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* of this method, q1 and q2 are empty, and their items have been merged
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* into the returned queue.
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* @param q1 is LinkedQueue of Comparable objects, sorted from smallest
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* to largest.
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* @param q2 is LinkedQueue of Comparable objects, sorted from smallest
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* to largest.
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* @return a LinkedQueue containing all the Comparable objects from q1
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* and q2 (and nothing else), sorted from smallest to largest.
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**/
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public static LinkedQueue mergeSortedQueues(LinkedQueue q1, LinkedQueue q2) {
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// Replace the following line with your solution.
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return null;
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}
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/**
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* partition() partitions qIn using the pivot item. On completion of
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* this method, qIn is empty, and its items have been moved to qSmall,
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* qEquals, and qLarge, according to their relationship to the pivot.
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* @param qIn is a LinkedQueue of Comparable objects.
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* @param pivot is a Comparable item used for partitioning.
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* @param qSmall is a LinkedQueue, in which all items less than pivot
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* will be enqueued.
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* @param qEquals is a LinkedQueue, in which all items equal to the pivot
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* will be enqueued.
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* @param qLarge is a LinkedQueue, in which all items greater than pivot
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* will be enqueued.
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**/
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public static void partition(LinkedQueue qIn, Comparable pivot,
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LinkedQueue qSmall, LinkedQueue qEquals,
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LinkedQueue qLarge) {
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// Your solution here.
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}
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/**
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* mergeSort() sorts q from smallest to largest using mergesort.
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* @param q is a LinkedQueue of Comparable objects.
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**/
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public static void mergeSort(LinkedQueue q) {
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// Your solution here.
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}
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/**
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* quickSort() sorts q from smallest to largest using quicksort.
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* @param q is a LinkedQueue of Comparable objects.
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**/
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public static void quickSort(LinkedQueue q) {
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// Your solution here.
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}
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/**
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* makeRandom() builds a LinkedQueue of the indicated size containing
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* Integer items. The items are randomly chosen between 0 and size - 1.
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* @param size is the size of the resulting LinkedQueue.
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**/
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public static LinkedQueue makeRandom(int size) {
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LinkedQueue q = new LinkedQueue();
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for (int i = 0; i < size; i++) {
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q.enqueue(new Integer((int) (size * Math.random())));
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}
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return q;
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}
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/**
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* main() performs some tests on mergesort and quicksort. Feel free to add
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* more tests of your own to make sure your algorithms works on boundary
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* cases. Your test code will not be graded.
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**/
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public static void main(String [] args) {
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LinkedQueue q = makeRandom(10);
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System.out.println(q.toString());
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mergeSort(q);
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System.out.println(q.toString());
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q = makeRandom(10);
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System.out.println(q.toString());
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quickSort(q);
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System.out.println(q.toString());
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/* Remove these comments for Part III.
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Timer stopWatch = new Timer();
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q = makeRandom(SORTSIZE);
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stopWatch.start();
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mergeSort(q);
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stopWatch.stop();
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System.out.println("Mergesort time, " + SORTSIZE + " Integers: " +
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stopWatch.elapsed() + " msec.");
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stopWatch.reset();
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q = makeRandom(SORTSIZE);
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stopWatch.start();
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quickSort(q);
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stopWatch.stop();
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System.out.println("Quicksort time, " + SORTSIZE + " Integers: " +
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stopWatch.elapsed() + " msec.");
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*/
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}
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}

‎homework/src/main/java/com/offline/training/homework/hw7/Timer.java

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package com.offline.training.homework.hw7;
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/* Timer.java */
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/**
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* Implements a simple stopwatch/timer class based on wall-clock time.
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**/
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/**
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* RUNNING() == true <==> start() called with no corresponding
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* call to stop()
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*
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* All times are given in units of msec.
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**/
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public class Timer {
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private boolean running;
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private long tStart;
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private long tFinish;
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private long tAccum;
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/**
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* Initializes Timer to 0 msec
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**/
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public Timer() {
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reset();
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}
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/**
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* Starts the timer. Accumulates time across multiple calls to start.
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**/
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public void start() {
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running = true;
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tStart = System.currentTimeMillis();
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tFinish = tStart;
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}
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/**
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* Stops the timer. returns the time elapsed since the last matching call
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* to start(), or zero if no such matching call was made.
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**/
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public long stop() {
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tFinish = System.currentTimeMillis();
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if (running) {
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running = false;
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long diff = tFinish - tStart;
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tAccum += diff;
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return diff;
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}
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return 0;
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}
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/**
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* if RUNNING() ==> returns the time since last call to start()
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* if !RUNNING() ==> returns total elapsed time
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**/
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public long elapsed() {
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if (running) {
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return System.currentTimeMillis() - tStart;
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}
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return tAccum;
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}
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/**
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* Stops timing, if currently RUNNING(); resets
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* accumulated time to 0.
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*/
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public void reset() {
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running = false;
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tStart = 0;
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tFinish = 0;
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tAccum = 0;
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}
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}

‎homework/src/main/java/com/offline/training/homework/hw7/list/LinkedQueue.java

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/* LinkedQueue.java */
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package com.offline.training.homework.hw7.list;
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public class LinkedQueue implements Queue {
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private SListNode head;
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private SListNode tail;
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private int size;
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/**
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* LinkedQueue() constructs an empty queue.
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**/
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public LinkedQueue() {
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size = 0;
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head = null;
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tail = null;
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}
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/**
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* size() returns the size of this Queue.
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* @return the size of this Queue.
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* Performance: runs in O(1) time.
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**/
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public int size() {
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return size;
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}
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/**
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* isEmpty() returns true if this Queue is empty, false otherwise.
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* @return true if this Queue is empty, false otherwise.
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* Performance: runs in O(1) time.
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**/
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public boolean isEmpty() {
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return size == 0;
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}
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/**
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* enqueue() inserts an object at the end of the Queue.
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* @param item the item to be enqueued.
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**/
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public void enqueue(Object item) {
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if (head == null) {
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head = new SListNode(item);
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tail = head;
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} else {
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tail.next = new SListNode(item);
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tail = tail.next;
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}
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size++;
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}
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/**
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* dequeue() removes and returns the object at the front of the Queue.
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* @return the item dequeued.
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* @throws a QueueEmptyException if the Queue is empty.
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**/
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public Object dequeue() throws QueueEmptyException {
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if (head == null) {
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throw new QueueEmptyException();
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} else {
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Object o = head.item;
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head = head.next;
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size--;
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if (size == 0) {
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tail = null;
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}
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return o;
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}
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}
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/**
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* front() returns the object at the front of the Queue.
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* @return the item at the front of the Queue.
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* @throws a QueueEmptyException if the Queue is empty.
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**/
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public Object front() throws QueueEmptyException {
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if (head == null) {
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throw new QueueEmptyException();
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} else {
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return head.item;
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}
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}
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/**
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*
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* nth() returns the nth item in this LinkedQueue.
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* Items in the queue are numbered from 1.
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* @param n the number of the item to return.
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*/
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public Object nth(int n) {
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SListNode node = head;
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for (; n > 1; n--) {
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node = node.next;
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}
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return node.item;
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}
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/**
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* append() appends the contents of q onto the end of this LinkedQueue.
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* On completion, q is empty.
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* @param q the LinkedQueue whose contents should be appended onto this
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* LinkedQueue.
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**/
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public void append(LinkedQueue q) {
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if (head == null) {
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head = q.head;
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} else {
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tail.next = q.head;
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}
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if (q.head != null) {
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tail = q.tail;
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}
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size = size + q.size;
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q.head = null;
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q.tail = null;
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q.size = 0;
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}
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/**
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* toString() converts this queue to a String.
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**/
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public String toString() {
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String out = "[ ";
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try {
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for (int i = 0; i < size(); i++) {
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out = out + front() + " ";
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enqueue(dequeue());
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}
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} catch (QueueEmptyException uf) {
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System.err.println("Error: attempt to dequeue from empty queue.");
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}
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return out + "]";
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}
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}

‎homework/src/main/java/com/offline/training/homework/hw7/list/Queue.java

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/* Queue.java */
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package com.offline.training.homework.hw7.list;
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public interface Queue {
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/**
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* size() returns the size of this Queue.
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* @return the size of this Queue.
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* Performance: runs in O(1) time.
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**/
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public int size();
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/**
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* isEmpty() returns true if this Queue is empty, false otherwise.
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* @return true if this Queue is empty, false otherwise.
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* Performance: runs in O(1) time.
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**/
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public boolean isEmpty();
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/**
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* enqueue() inserts an object at the end of the Queue.
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* @param item the item to be enqueued.
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**/
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public void enqueue(Object item);
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/**
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* dequeue() removes and returns the object at the front of the Queue.
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* @return the item dequeued.
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* @throws a QueueEmptyException if the Queue is empty.
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**/
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public Object dequeue() throws QueueEmptyException;
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/**
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* front() returns the object at the front of the Queue.
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* @return the item at the front of the Queue.
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* @throws a QueueEmptyException if the Queue is empty.
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**/
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public Object front() throws QueueEmptyException;
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}

‎homework/src/main/java/com/offline/training/homework/hw7/list/QueueEmptyException.java

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/* QueueEmptyException.java */
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package com.offline.training.homework.hw7.list;
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public class QueueEmptyException extends Exception {
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public QueueEmptyException() {
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super();
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}
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public QueueEmptyException(String s) {
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super(s);
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}
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}

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