public void ReturnKthToLastTest_InvalidCases()
{
try
{
Question_2_2.ReturnKthToLast(null, 2);
Assert.Fail("ArgumentNullException was not thrown for null list.");
}
catch (ArgumentNullException) { }
try
{
Question_2_2.ReturnKthToLast(new LinkedList(), 2);
Assert.Fail("ArgumentNullException was not thrown for empty list.");
}
catch (ArgumentNullException) { }
try
{
int k = 2;
Question_2_2.ReturnKthToLast(new LinkedList(new int[] { 1 }), k);
Assert.Fail($"ArgumentOutOfRangeException was not thrown for invalid k={k}.");
}
catch (ArgumentOutOfRangeException) { }
try
{
int k = -1;
Question_2_2.ReturnKthToLast(new LinkedList(new int[] { 1 }), k);
Assert.Fail($"ArgumentOutOfRangeException was not thrown for invalid k={k}.");
}
catch (ArgumentOutOfRangeException) { }
}
public void Question_2_2_EdgeCases()
{
// 1 => 1 - Only one element.
var l1 = ListHelpers.CreateLinkedList(1);
Assert.AreEqual(1, Question_2_2.ReturnKthToLast(l1, 0));
}
private void ValidateResult <T>(Node <T> expected, Node <T> input, int k)
where T : IEquatable <T>
{
var inputCopy = ListHelpers.CloneList(input);
var inputCopy2 = ListHelpers.CloneList(input);
Assert.AreEqual(expected, Question_2_2.ReturnKthToLast(inputCopy, k));
}
public void ReturnKthToLastTest(int k, int expected)
{
var testList = new LinkedList(new int[] { 1, 2, 3, 2, 1, 4, 5, 6, 5, 4, 3, 2, 1, 10, 1 });
int result = Question_2_2.ReturnKthToLast(testList, k);
Assert.AreEqual(expected, result, $"{k}th element {expected} is expected but got {result}.");
result = Question_2_2.ReturnKthToLastRecursive(testList, k);
Assert.AreEqual(expected, result, $"{k}th element {expected} is expected but got {result} - recursive.");
result = Question_2_2.ReturnKthToLastOnePass(testList, k);
Assert.AreEqual(expected, result, $"{k}th element {expected} is expected but got {result} - one pass.");
}
public void Question_2_2_BasicCases()
{
// Cover all case for K for a list of length 6.
const int NumberElements = 6;
var list = ListHelpers.CreateLinkedList(Enumerable.Range(0, NumberElements).Reverse().ToArray());
for (var i = 0; i < NumberElements; i++)
{
var listCopy = ListHelpers.CloneList(list);
var result = Question_2_2.ReturnKthToLast(listCopy, i);
Assert.AreEqual(i, result);
}
}
public void Question_2_2_InvalidCases()
{
Node <int> invalidHead = null;
var head = ListHelpers.CreateLinkedList(1);
TestHelpers.AssertExceptionThrown(
() => Question_2_2.ReturnKthToLast(invalidHead, 0),
typeof(ArgumentNullException));
TestHelpers.AssertExceptionThrown(
() => Question_2_2.ReturnKthToLast(head, -1),
typeof(ArgumentOutOfRangeException));
TestHelpers.AssertExceptionThrown(
() => Question_2_2.ReturnKthToLast(head, 1),
typeof(ArgumentOutOfRangeException));
}
public void ReturnKthToLastOnePassTest_InvalidCases()
{
try
{
int k = 2;
Question_2_2.ReturnKthToLastOnePass(new LinkedList(new int[] { 1 }), k);
Assert.Fail($"ArgumentOutOfRangeException was not thrown for invalid k={k}.");
}
catch (ArgumentOutOfRangeException) { }
try
{
int k = -1;
Question_2_2.ReturnKthToLastOnePass(new LinkedList(new int[] { 1 }), k);
Assert.Fail($"ArgumentOutOfRangeException was not thrown for invalid k={k}.");
}
catch (ArgumentOutOfRangeException) { }
}
