private static Node <T> AddLoop <T>(Node <T> head, params T[] loop)
where T : IEquatable <T>
{
while (head?.Next != null)
{
head = head.Next;
}
var loopStart = ListHelpers.CreateLinkedList(loop);
var loopEnd = loopStart;
while (loopEnd.Next != null)
{
loopEnd = loopEnd.Next;
}
if (head != null)
{
head.Next = loopStart;
}
loopEnd.Next = loopStart;
return(loopStart);
}
public void Question_2_7_BasicCases()
{
var l1 = ListHelpers.CreateLinkedList(1, 2);
var l2 = ListHelpers.CreateLinkedList(3, 4);
var intersection = ListHelpers.CreateLinkedList(5, 6);
AddIntersection(l1, l2, intersection);
Validate(intersection, l1, l2);
l1 = ListHelpers.CreateLinkedList(1);
l2 = ListHelpers.CreateLinkedList(2);
intersection = ListHelpers.CreateLinkedList(3);
AddIntersection(l1, l2, intersection);
Validate(intersection, l1, l2);
l1 = ListHelpers.CreateLinkedList(1, 2, 3, 4);
l2 = ListHelpers.CreateLinkedList(2);
intersection = ListHelpers.CreateLinkedList(5);
AddIntersection(l1, l2, intersection);
Validate(intersection, l1, l2);
l1 = ListHelpers.CreateLinkedList(1, 2, 3, 4);
l2 = ListHelpers.CreateLinkedList(2, 2, 2, 2);
intersection = ListHelpers.CreateLinkedList(5, 4, 3, 2, 3);
AddIntersection(l1, l2, intersection);
Validate(intersection, l1, l2);
intersection = ListHelpers.CreateLinkedList(4);
Validate(intersection, intersection, intersection);
}
public void Question_2_1_BasicCases()
{
// No duplicates
var l1 = ListHelpers.CreateLinkedList(1, 2, 3);
var expected = ListHelpers.CloneList(l1);
this.ValidateResult(expected, l1);
// Several (3x) duplicates
var l2 = ListHelpers.CreateLinkedList(1, 1, 1);
expected = ListHelpers.CreateLinkedList(1);
this.ValidateResult(expected, l2);
// two sets of duplicates, one next to each other one separated
var l3 = ListHelpers.CreateLinkedList(1, 2, 2, 1);
expected = ListHelpers.CreateLinkedList(1, 2);
this.ValidateResult(expected, l3);
// 3x duplicate case split up
var l4 = ListHelpers.CreateLinkedList(1, 2, 2, 3, 2);
expected = ListHelpers.CreateLinkedList(1, 2, 3);
this.ValidateResult(expected, l4);
// Several duplicates in the list
var l5 = ListHelpers.CreateLinkedList(1, 2, 2, 1, 3, 4, 7, 5, 6, 2, 3, 4, 5, 6);
expected = ListHelpers.CreateLinkedList(1, 2, 3, 4, 7, 5, 6);
this.ValidateResult(expected, l5);
}
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));
}
public void Question_2_6_EdgeCases()
{
var l1 = ListHelpers.CreateLinkedList(1);
var l2 = ListHelpers.CreateLinkedList(2, 2);
var l3 = ListHelpers.CreateLinkedList(1, 2);
Validate(true, l1);
Validate(true, l2);
Validate(false, l3);
}
public void Question_2_3_InvalidCases()
{
// Remove end of list
var l3 = ListHelpers.CreateLinkedList(1, 2);
var expected = ListHelpers.CreateLinkedList(1);
TestHelpers.AssertExceptionThrown(() => Question_2_3.RemoveMiddleNode(l3.Next), typeof(ArgumentException));
// Pass null node.
Node <int> head = null;
TestHelpers.AssertExceptionThrown(() => Question_2_3.RemoveMiddleNode(head), typeof(ArgumentNullException));
}
public void Question_2_6_BasicCases()
{
var l1 = ListHelpers.CreateLinkedList(1, 2, 1);
var l2 = ListHelpers.CreateLinkedList(1, 2, 2, 2, 2, 2);
var l3 = ListHelpers.CreateLinkedList(1, 1, 1, 1, 1);
var l4 = ListHelpers.CreateLinkedList(1, 2, 3, 4, 5);
var l5 = ListHelpers.CreateLinkedList(1, 2, 2, 2, 2, 2, 1);
Validate(true, l1);
Validate(false, l2);
Validate(true, l3);
Validate(false, l4);
Validate(true, l5);
}
public void Question_2_4_EdgeCases()
{
// One node list, no change
var l1 = ListHelpers.CreateLinkedList(1);
ValidateResult(l1, 0, 1);
ValidateResult(l1, 1, 1);
ValidateResult(l1, 2, 1);
// List with all the same values
var l2 = ListHelpers.CreateLinkedList(2, 2, 2, 2, 2, 2);
ValidateResult(l2, 2, 2, 2, 2, 2, 2, 2);
}
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_4_BasicCases()
{
// List already partitioned.
var l1 = ListHelpers.CreateLinkedList(1, 2, 3);
ValidateResult(l1, 2, 1, 2, 3);
// List already partitioned.
var l2 = ListHelpers.CreateLinkedList(1, 2, 3);
ValidateResult(l2, 1, 1, 2, 3);
// List needs to be partitioned.
var l3 = ListHelpers.CreateLinkedList(5, 4, 3, 2, 1);
ValidateResult(l3, 3, 2, 1, 3, 5, 4);
}
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 Question_2_8_BasicCases()
{
var list = ListHelpers.CreateLinkedList(1, 2, 3);
var loopStart = AddLoop(list, 4, 5, 6);
Validate(loopStart, list);
list = ListHelpers.CreateLinkedList(1);
loopStart = AddLoop(list, 4, 5, 6);
Validate(loopStart, list);
list = ListHelpers.CreateLinkedList(1);
loopStart = AddLoop(list, 4);
Validate(loopStart, list);
loopStart = AddLoop(null, 5);
Validate(loopStart, loopStart);
}
public void Question_2_1_EdgeCases()
{
// 1 => 1 - Only one element.
var l1 = ListHelpers.CreateLinkedList(1);
var expected = ListHelpers.CloneList(l1);
this.ValidateResult(expected, l1);
// 1, 1 => 1 - Only duplicate elements
var l2 = ListHelpers.CreateLinkedList(1, 1);
expected = ListHelpers.CreateLinkedList(1);
this.ValidateResult(expected, l2);
// 1, 2, 2 => 1, 2 - Last element duplicated
var l3 = ListHelpers.CreateLinkedList(1, 2, 2);
expected = ListHelpers.CreateLinkedList(1, 2);
this.ValidateResult(expected, l3);
}
public void Question_2_3_BasicCases()
{
// Remove 1 middle node: 1, 2, 3 => 1, 3
var l1 = ListHelpers.CreateLinkedList(1, 2, 3);
var expected = ListHelpers.CreateLinkedList(1, 3);
Question_2_3.RemoveMiddleNode(l1.Next);
ListHelpers.ValidateLinkedListContent(expected, l1);
// Remove 2: 1, 2, 3, 4 => 1, 4
var l2 = ListHelpers.CreateLinkedList(1, 2, 3, 4);
expected = ListHelpers.CreateLinkedList(1, 4);
Question_2_3.RemoveMiddleNode(l2.Next);
Question_2_3.RemoveMiddleNode(l2.Next);
ListHelpers.ValidateLinkedListContent(expected, l2);
// Remove 1 node from big list: 1, 2, 3, 4, 5, 6, 7 => 1, 2, 3, 5, 6, 7
var l3 = ListHelpers.CreateLinkedList(1, 2, 3, 4, 5, 6, 7);
expected = ListHelpers.CreateLinkedList(1, 2, 3, 5, 6, 7);
Question_2_3.RemoveMiddleNode(l3.Next.Next.Next);
ListHelpers.ValidateLinkedListContent(expected, l3);
}
private static Node <Digit> CreateDigitList(int num, bool reversed = false)
{
var list = CreateList(num, reversed);
return(ListHelpers.CreateLinkedList(list.Select(n => new Digit(n)).ToArray()));
}