public int Remove()
{
int value;
if (_head == null)
{
throw new IndexOutOfRangeException("List is empty");
}
else if (_head.Next == null)
{
value = _head.Value;
_head = null;
}
else
{
SLNode runner = _head;
while (runner.Next.Next != null)
{
runner = runner.Next;
}
value = runner.Next.Value;
runner.Next = null;
}
_length--;
return(value);
}
public void Delete(int target)
{
Console.WriteLine("Attempting to delete {0}...\n", target);
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
SLNode targetNode = null;
SLNode cur = header;
bool deleted = false;
for (int i = maxLevel - 1; i >= 0; i--)
{
Console.WriteLine("On level {0}\nOn header", i);
while (cur.forward[i].key < target)
{
Console.WriteLine("On node {0}", cur.forward[i].key);
cur = cur.forward[i];
}
if (cur.forward[i].key == target)
{
Console.WriteLine("Target found at level {0}", i);
targetNode = cur.forward[i];
cur.forward[i] = targetNode.forward[i];
Console.WriteLine("Spliced out target at level {0}\n", i);
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
deleted = true;
}
if (!deleted)
{
Console.WriteLine("Target not found on level {0}\n", i);
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
}
}
Console.WriteLine("\nLoop complete, all levels checked");
if (deleted)
{
Console.WriteLine("target deleted, Delete() complete\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
count--;
}
else
{
Console.WriteLine("target not found, Delete() complete\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
}
PrintGraphicalList();
}
public SLNode(int val)
{
Value = val;
Next = null;
Child = null;
isTail = false;
}
public int RemoveAt(int index)
{
int value;
if (index < 0 || index >= _length)
{
throw new IndexOutOfRangeException("Index not in list.");
}
else if (index == _length - 1)
{
return(this.Remove());
}
else if (index == 0)
{
value = _head.Value;
_head = _head.Next;
}
else
{
SLNode runner = _head;
while (index != 1)
{
runner = runner.Next;
index--;
}
value = runner.Next.Value;
runner.Next = runner.Next.Next;
}
_length--;
return(value);
}
public void PrintListContents()
{
SLNode cur = header;
while (cur.forward[0].forward[0] != null)
{
Console.WriteLine("key: {0} height: {1}", cur.forward[0].key, cur.forward[0].height);
cur = cur.forward[0];
}
}
public void PrintGraphicalList()
{
Console.WriteLine("SkipList visual:\n");
SLNode cur = header;
int[] items = new int[count];
int[] lengths = new int[count];
int[] heights = new int[count];
int counter = 0;
StringBuilder stringBuilder = new StringBuilder();
while (cur.forward[0].forward[0] != null)
{
items[counter] = cur.forward[0].key;
if (cur.forward[0].key < 10)
{
lengths[counter] = 1;
}
else if (cur.forward[0].key < 100)
{
lengths[counter] = 2;
}
else
{
lengths[counter] = 3;
}
heights[counter] = cur.forward[0].height;
counter++;
cur = cur.forward[0];
}
for (int i = maxLevel; i > 0; i--)
{
stringBuilder.Append("[]");
for (int j = 0; j < count; j++)
{
if (heights[j] >= i)
{
stringBuilder.Append("-" + items[j] + "-");
}
else
{
stringBuilder.Append(new String('-', lengths[j] + 2));
}
}
stringBuilder.Append("[]\n");
}
stringBuilder.Append("\n");
Console.Write(stringBuilder);
}
public override string ToString()
{
StringBuilder sb = new StringBuilder();
SLNode runner = _head;
while (runner != null)
{
sb.Append($"{runner} -> ");
runner = runner.Next;
}
return(sb.ToString());
}
public SkipList(int maxLevel)
{
this.maxLevel = maxLevel;
// SL will contain values between 0 and 999
// Warning - nothing has been done to ensure this
header = new SLNode(-1, maxLevel);
sentinel = new SLNode(1000, maxLevel);
for (int i = 0; i < maxLevel; i++)
{
header.forward[i] = sentinel;
}
}
static void Main(string[] args)
{
SLL list1 = new SLL();
list1.Add(1);
list1.Add(2);
list1.Add(3);
list1.Add(4);
list1.Add(5);
SLNode someNode = list1.Head.Next;
SLNode tail = list1.Head.Next.Next.Next.Next;
tail.Next = someNode;
// list1.Print();
Console.WriteLine(list1.HasLoop());
}
public static void DisplayAllList()
{
Console.WriteLine("****** SkipList ******");
for (int i = 0; i <= maxLevel - 1; i++)
{
SLNode node = header.forward[i];
Console.WriteLine("Level {0}", i);
Console.WriteLine("ID Names");
while (node.forward[i] != null)
{
Console.WriteLine("{0} {1}", node.key, node.name);
node = node.forward[i];
}
Console.WriteLine(" ");
}
}
public static void PrintList()
{
SLNode node = header.forward[0];
Console.WriteLine("****** EmployeeList ******");
Console.WriteLine("ID Names");
for (int i = 0; i <= maxLevel - 1; i++)
{
while (node.forward[i] != null)
{
Console.WriteLine("{0} {1}", node.key, node.name);
node = node.forward[i];
}
}
Console.WriteLine(" ");
}
public void Add(int value)
{
if (_head == null)
{
_head = new SLNode(value);
}
else
{
SLNode runner = _head;
while (runner.Next != null)
{
runner = runner.Next;
}
runner.Next = new SLNode(value);
}
_length++;
}
public bool Search(int searchKey)
{
Console.WriteLine("Searching for key {0}...\n", searchKey);
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
SLNode cur = header;
for (int i = maxLevel - 1; i >= 0; i--)
{
Console.WriteLine("On level {0}\nOn header", i);
while (cur.forward[i].key < searchKey)
{
Console.WriteLine("On node {0}", cur.forward[i].key);
cur = cur.forward[i];
}
}
Console.WriteLine("\nLoop complete, all levels checked");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
cur = cur.forward[0];
Console.WriteLine("Seeing if next item {0} matches searchKey", cur.key);
if (cur.key == searchKey)
{
Console.WriteLine("Found match, Search() complete\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
return(true);
}
else
{
Console.WriteLine("Match not found, Search() complete\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
return(false);
}
}
public SkipListConsoleOutput(int maxLevel)
{
Console.WriteLine("SkipList with max height" +
" {0} created\n", maxLevel);
this.maxLevel = maxLevel;
// SL will contain positive values between 0 and 100
header = new SLNode(-1, maxLevel);
sentinel = new SLNode(1000, maxLevel);
for (int i = 0; i < maxLevel; i++)
{
header.forward[i] = sentinel;
}
PrintGraphicalList();
}
public int Find(int val)
{
int index = 0;
if (_head != null)
{
SLNode runner = _head;
while (runner != null)
{
if (runner.Value == val)
{
return(index);
}
index++;
runner = runner.Next;
}
}
return(-1);
}
public void Delete(int target)
{
SLNode targetNode;
SLNode cur = header;
for (int i = maxLevel - 1; i >= 0; i--)
{
while (cur.forward[i].key < target)
{
cur = cur.forward[i];
}
// splice out
if (cur.forward[i].key == target)
{
targetNode = cur.forward[i];
cur.forward[i] = targetNode.forward[i];
}
}
}
public bool Search(int searchKey)
{
SLNode cur = header;
for (int i = maxLevel - 1; i >= 0; i--)
{
while (cur.forward[i].key < searchKey)
{
cur = cur.forward[i];
}
}
cur = cur.forward[0];
if (cur.key == searchKey)
{
return(true);
}
else
{
return(false);
}
}
public void Insert(int searchKey)
{
SLNode sLNode = new SLNode(searchKey, GenerateLevel());
SLNode[] update = new SLNode[maxLevel];
SLNode cur = header;
for (int i = maxLevel - 1; i >= 0; i--)
{
while (cur.forward[i].key < searchKey)
{
cur = cur.forward[i];
}
update[i] = cur;
}
// stitch in
for (int i = 0; i < sLNode.height; i++)
{
sLNode.forward[i] = update[i].forward[i];
update[i].forward[i] = sLNode;
}
}
public static void Main(string[] args)
{
maxLevel = 5; // this sets the max leave of the skip list
// SL will contain values between 1000 and 9999
// Warning - nothing has been done to ensure this
header = new SLNode(1000, "Start of list", maxLevel);
sentinel = new SLNode(9999, "End of List", maxLevel);
for (int i = 0; i < maxLevel; i++)
{
header.forward[i] = sentinel;
}
// Data //
Insert(1015, "Office_Lady");
Insert(1050, "Desk_Gentleman");
Insert(1020, "New_Girl");
Insert(1001, "Boss_Man");
Insert(1070, "Boss_Woman");
Insert(1060, "Office_Clown");
Insert(1040, "Cat_Man");
// UI //
String userResponse = "";
Console.WriteLine("Type COMMANDS to get a list of commands.");
while (userResponse != "end")
{
Console.Write("//");
userResponse = Console.ReadLine().ToLower();
switch (userResponse)
{
case "?":
case "help":
case "commands":
Console.WriteLine("List of Commands:");
Console.WriteLine("");
Console.WriteLine("COMMANDS");
Console.WriteLine(" List commands availible.");
Console.WriteLine("LIST");
Console.WriteLine(" List all employees in the system.");
Console.WriteLine("LIST_ALL");
Console.WriteLine(" List all layers of the SkipList.");
Console.WriteLine("ADD");
Console.WriteLine(" Add a new employee and ID Number");
Console.WriteLine("REMOVE");
Console.WriteLine(" Delete an employee by their ID Number");
Console.WriteLine("FIND");
Console.WriteLine(" Looks through the list of employees to see if a certain ID Number is in uses.");
Console.WriteLine("END");
Console.WriteLine(" End program.");
break;
case "list":
PrintList();
break;
case "list_all":
DisplayAllList();
break;
case "add":
Console.WriteLine("What is the new employee's ID? (must between 1000 and 9999 in addtion to not already being in uses.)");
Console.Write("//");
int newID = int.Parse(Console.ReadLine());
while (newID < 1000 || newID > 10000)
{
Console.WriteLine("Employee's ID {0} is out of range!!", newID);
Console.WriteLine("Try another ID number.");
Console.Write("//");
newID = int.Parse(Console.ReadLine());
}
while (Search(newID) == true)
{
Console.WriteLine("Employee with the ID {0} already exist!!!", newID);
Console.WriteLine("Try another ID number.");
Console.Write("//");
newID = int.Parse(Console.ReadLine());
}
Console.WriteLine("New Employee's name?");
Console.Write("//");
String newName = Console.ReadLine();
Insert(newID, newName);
Console.WriteLine("New Employee added.");
PrintList();
break;
case "remove":
PrintList();
Console.WriteLine("What is the Employee's ID that is to be deleted?");
int deleteID = int.Parse(Console.ReadLine());
if (Search(deleteID))
{
Delete(deleteID);
Console.WriteLine("Employee with the ID of {0} removed.", deleteID);
}
else
{
Console.WriteLine("Employee with the ID of {0} could not be found.", deleteID);
}
break;
case "find":
Console.WriteLine("Type in Employee's ID");
Console.Write("//");
int searchID = int.Parse(Console.ReadLine());
while (searchID < 1000 || searchID > 10000)
{
Console.WriteLine("Employee ID {0} is out of range!!", searchID);
Console.WriteLine("Try another ID number.");
Console.Write("//");
newID = int.Parse(Console.ReadLine());
}
if (Search(searchID))
{
Console.WriteLine("An Employee with the ID {0} exists", searchID);
}
else
{
Console.WriteLine("Did not find an Employee with the ID {0}", searchID);
}
break;
case "end":
break;
default:
Console.WriteLine("Command Unkown");
Console.WriteLine("");
break;
}
}
Console.WriteLine("Program END");
}
///<summary>Set <see cref="SLNode"/> in <see cref="Next"/> array.</summary>
///<param name="index">Index where new node will be inserted</param>
///<param name="next">New node to insert</param>
///<exception cref="IndexOutOfBoundsException"/>
public void SetNext(int index, SLNode <T> next)
{
Next[index] = next;
}
public SLList()
{
_head = null;
_length = 0;
}
public SLNode(int value, SLNode next = null)
{
Value = value;
Next = next;
}
public void Insert(int searchKey)
{
Console.WriteLine("Inserting key {0}...\n", searchKey);
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
SLNode[] update = new SLNode[maxLevel];
SLNode sLNode = new SLNode(searchKey, GenerateLevel());
SLNode cur = header;
for (int i = maxLevel - 1; i >= 0; i--)
{
Console.WriteLine("On level {0}", i);
while (cur.forward[i].key < searchKey)
{
cur = cur.forward[i];
Console.WriteLine("cur set to {0}", cur.key);
}
update[i] = cur;
if (cur.key == -1)
{
Console.WriteLine("Set update[{0}] to header\n", i);
}
else
{
Console.WriteLine("Set update[{0}] to node {1}\n", i, cur.key);
}
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
}
// stitch it in
Console.WriteLine("Splicing in new node...\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
for (int i = 0; i < sLNode.height; i++)
{
if (update[i].forward[i].key == 1000)
{
Console.WriteLine("Set new node's forward[{0}] to sentinel", i);
}
else
{
Console.WriteLine("Set new node's forward[{0}] to node {1}", i, update[i].forward[i].key);
}
sLNode.forward[i] = update[i].forward[i];
if (update[i].key == -1)
{
Console.WriteLine("Set header's forward[{0}] to new node\n", i);
}
else
{
Console.WriteLine("Set node {0}'s forward[{1}] to new node\n", update[i].key, i);
}
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
update[i].forward[i] = sLNode;
}
count++;
Console.WriteLine("Insert() complete\n");
while (Console.ReadKey().Key != ConsoleKey.Enter)
{
}
PrintGraphicalList();
}
