Question

Please help complete the items marked TODO in the code and get the tests to pass:

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class TestPerformance {

  // TODO run test and record running times for SIZE = 10, 100, 1000, 10000, ...
  // (choose in conjunction with REPS below up to an upper limit where the clock
  // running time is in the tens of seconds)
  // TODO (optional) refactor to DRY
  // TODO answer: which of the two lists performs better as the size increases?
  private final int SIZE = 10;

  // TODO choose this value in such a way that you can observe an actual effect
  // for increasing problem sizes
  private final int REPS = 1000000;

  private List<Integer> arrayList;

  private List<Integer> linkedList;

  @Before
  public void setUp() throws Exception {
    arrayList = new ArrayList<Integer>(SIZE);
    linkedList = new LinkedList<Integer>();
    for (int i = 0; i < SIZE; i++) {
      arrayList.add(i);
      linkedList.add(i);
    }
  }

  @After
  public void tearDown() throws Exception {
    arrayList = null;
    linkedList = null;
  }

  @Test
  public void testLinkedListAddRemove() {
    for (int r = 0; r < REPS; r++) {
      linkedList.add(0, 77);
      linkedList.remove(0);
    }
  }

  @Test
  public void testArrayListAddRemove() {
    for (int r = 0; r < REPS; r++) {
      arrayList.add(0, 77);
      arrayList.remove(0);
    }
  }

  @Test
  public void testLinkedListAccess() {
    long sum = 0;
    for (int r = 0; r < REPS; r++) {
      sum += linkedList.get(r % SIZE);
    }
  }

  @Test
  public void testArrayListAccess() {
    long sum = 0;
    for (int r = 0; r < REPS; r++) {
      sum += arrayList.get(r % SIZE);
    }
  }
}

Answer 1

Please let me know if you have any doubts or you want me to modify the answer. And if you find this answer useful then don't forget to rate my answer as thumps up. Thank you! :)

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class TestPerformance {

    // TODO run test and record running times for SIZE = 10, 100, 1000, 10000
    // which of the two lists performs better as the size increases?
    private final int SIZE = 10;
    //size 10 89 ms
    //size 100 119 ms
    //size 1000 606 ms
    //size 10000 901 ms

    private final int REPS = 1000000;

    private List<Integer> arrayList;

    private List<Integer> linkedList;

    @Before
    public void setUp() throws Exception {
        arrayList = new ArrayList<Integer>(SIZE);
        linkedList = new LinkedList<Integer>();
        for (int i = 0; i < SIZE; i++) {
            arrayList.add(i);
            linkedList.add(i);
        }
    }

    @After
    public void tearDown() throws Exception {
        arrayList = null;
        linkedList = null;
    }

    @Test
    public void testLinkedListAddRemove() {
        for (int r = 0; r < REPS; r++) {
            linkedList.add(0, 77);
            linkedList.remove(0);
        }
    }

    @Test
    public void testArrayListAddRemove() {
        for (int r = 0; r < REPS; r++) {
            arrayList.add(0, 77);
            arrayList.remove(0);
        }
    }

    @Test
    public void testLinkedListAccess() {
        long sum = 0;
        for (int r = 0; r < REPS; r++) {
            sum += linkedList.get(r % SIZE);
        }
    }

    @Test
    public void testArrayListAccess() {
        long sum = 0;
        for (int r = 0; r < REPS; r++) {
            sum += arrayList.get(r % SIZE);
        }
    }
}

TestPerformance [~/ldeaProjects/Test Performance]- .../src/TestPerformance.java [TestPerformance] TestPerformance src TestPerformance Main c TestPerformance.java 3 Project import java. util. ArrayList; import java.util. LinkedList; import java.util. List ; vTestPerformance /ldea Projects/Test Performance .idea ero G TestPerformance import org.junit. After; TestPerformance.iml import org. unit Test: nsoles public class Test Performance { / TODO run test and record running times for SIZE 18, 1ee, 10e0, 10000 11 rforms better as the size increases? rivate final int SIZE 10: //size 18 89 ms 14 isize 1088 606 ms //size 10888 901 ms 17 private final int REPS = 1000000; 20 private List<Integer arrayList; private List<Integer> linked List; 23 25 @Before public void setUp() throws Exception {_ 28 TZE LinkedList = new LinkedListsInteger>(): for (int i = 0; i < SIZE; i++) { 29 linkedlist.add(1): 25 32 BAfter pub arrayList = null: linked List =null: 35 throws Exception 27 38 39 @Test public void testLinkedListAddRemove( 42 linkedList.add index: 0. element: 77): linkedList.remove( Index: 0); 45 TestPerformance SIZE 12:4 LF UTF-8 0