listAlgorithms/TestListAlgorithms.java

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package listAlgorithms;

import static org.junit.Assert.*;

import org.junit.Test;

public class TestListAlgorithms {

    @Test
    public void testReverse() {
        Character[] vals = new Character[] { 'A', 'B', 'C', 'D', 'E' };
        Character[] rvals = new Character[] { 'E', 'D', 'C', 'B', 'A' };
        ListNode<Character> list = Algorithms.buildList(vals);
        ListNode<Character> rlist = Algorithms.buildList(rvals);
        ListNode<Character> newList = Algorithms.reverse(list);
        assertTrue("List reverse failed", Algorithms.listEquals(rlist, newList));
    }

    @SuppressWarnings("javadoc")
    @Test
    public void testDedup() {
        Character[] vals = new Character[] { 'A', 'B', 'B', 'C', 'D', 'D', 'D',
                'D', 'E', 'E', 'F', 'G', 'H', 'H', 'H' };
        Character[] dedupVals = new Character[] { 'A', 'B', 'C', 'D', 'E', 'F',
                'G', 'H' };
        Character[] aVals = new Character[] { 'A', 'A', 'A', 'A', 'A', 'A', 'A' };
        ListNode<Character> check = Algorithms.buildList(dedupVals);
        ListNode<Character> list = Algorithms.buildList(vals);
        Algorithms.dedup(list);
        assertTrue("1. List dedup failed", Algorithms.listEquals(list, check));
        list = Algorithms.buildList(aVals);
        check = Algorithms.buildList(new Character[] { 'A' });
        Algorithms.dedup(list);
        assertTrue("2. List dedup failed", Algorithms.listEquals(list, check));
    }

    @SuppressWarnings("javadoc")
    @Test
    public void testKthElement() {
        Character[] vals = new Character[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G',
                'H' };
        ListNode<Character> list = Algorithms.buildList(vals);
        Character elemVal = Algorithms.kthFromEnd(list, 2).getValue();
        assertTrue("1. should have returned F, but returned " + elemVal,
                elemVal.compareTo('F') == 0);
        elemVal = Algorithms.kthFromEnd(list, 0).getValue();
        assertTrue("2. should have returned H, but returned " + elemVal,
                elemVal.compareTo('H') == 0);
        elemVal = Algorithms.kthFromEnd(list, 7).getValue();
        assertTrue("3. should have returned A, but returned " + elemVal,
                elemVal.compareTo('A') == 0);
    }
}