public LinkedList BuildSampleList()
{
LinkedList head = new LinkedList(1);
head.Next = new LinkedList(2);
head.Next.Next = new LinkedList(3);
return head;
}
//Question -1, write a function that counts the number of times a value is repeated in a given list
public int CountNumberOfOccurance(LinkedList head, int ValueToCheck)
{
if (head == null) return 0;
LinkedList current = head;
int count = 0;
while ( current!=null)
{
if (current.Data == ValueToCheck)
count++;
current = current.Next;
}
return count;
}
//question -8 Given two lists, append one of them at the end of the other and destroy the second list
public void Append(ref LinkedList headA, ref LinkedList headB)
{
if (headA == null)
headA = headB;
else
{
LinkedList current = headA;
while (current.Next!=null)
{
current = current.Next;
}
current.Next = headB;
headB = null;
}
}
//Question - 12 write a function, given a list, which will split the list in alternating manner.
public void AlternateSplit(LinkedList head, ref LinkedList headA, ref LinkedList headB)
{
if (head == null) return;
LinkedList current = head;
LinkedList currentA = headA;
LinkedList currentB = headB;
while (current != null)
{
head = current.Next;
headA = current;
current.Next = currentA;
currentA = headA;
current = head;
if (current != null)
{
head = current.Next;
headB = current;
current.Next = currentB;
currentB = headB;
current = head;
}
}
}
public int Size(LinkedList head)
{
if (head==null) return 0;
int count=0;
while (head!=null)
{
head = head.Next;
count++;
}
return count;
}
//Question - 12 Shuffel merge, given two list, merge them to produce one list by taking one node at a time.
public void ShuffelMerge(ref LinkedList head, LinkedList headA, LinkedList headB)
{
if (headA==null && headB==null) return;
LinkedList current=head;
LinkedList currentA=headA;
LinkedList currentB=headB;
while (currentA!=null || currentB!=null)
{
if (currentA!=null)
{
headA=currentA.Next;
head=currentA;
currentA.Next=current;
current=head;
currentA=headA;
}
if (currentB!=null)
{
headB=currentB.Next;
head=currentB;
currentB.Next = current;
current=head;
currentB=headB;
}
}
}
//Question - 10 Remove Duplicates given a sorted list in increasing order/remove duplicates by traversing only ones.
public void RemoveDuplicates( ref LinkedList head)
{
if (head == null || head.Next == null)
return; // there is no duplicates;
LinkedList slow = head;
LinkedList fast = head.Next;
while (fast!=null)
{
if ( slow.Data==fast.Data)
{
slow.Next = fast.Next;
fast = null;
fast = slow.Next;
}
else
{
slow = fast;
fast = fast.Next;
}
}
}
public void PushAtTail(ref LinkedList head, int newData)
{
LinkedList temp=new LinkedList(newData);
if (head == null) head = temp;
else
{
LinkedList current=head;
while (current.Next!=null)
{
current = current.Next;
}
current.Next = temp;
temp.Next = null;
}
}
public LinkedList DeleteNthNodeFromLast(ref LinkedList head, int n)
{
if (head == null) return null;
// LinkedList slow = head;
// LinkedList fast = head;
// int gap=1;
// if (head.Next == null && n == 1) return null;
// while (fast!=null && gap<n)
// {
// fast = fast.Next;
// gap++;
// }
// if (fast == null & gap < n)
// return head;
// while (fast.Next!=null)
// {
// fast = fast.Next;
// slow = slow.Next;
// }
// LinkedList temp = slow.Next;
// slow.Next = temp.Next;
// temp.Next = null;
// return head;
return head;
}
//Question-11 givent two lists, write a function which takes the second list elements and push it to the front of the first list
public void MoveNode(ref LinkedList headA, ref LinkedList headB)
{
if (headA == null)
{
headA = headB;
return;
}
LinkedList currentA = headA;
LinkedList currentB = headB;
while (currentB!=null)
{
headA = headB;
currentB = currentB.Next;
headB.Next = currentA;
currentA = headB;
headB = currentB;
}
}
//Question-5 given a list and index Nth, write a function to insert a data at the Nth location.
public void InsertNth(ref LinkedList head, int index, int newData)
{
LinkedList current = head;
LinkedList prev = head;
LinkedList tempNode = new LinkedList(newData);
if (index == 0)
{
head = tempNode;
tempNode.Next = current;
return;
}
for (int i = 0; i < index;i++)
{
if(current!=null)
{
prev = current;
current = current.Next;
}
if(i<index && current==null)
{
Console.WriteLine("invalid Index or index is out of the boundary of the list");
return;
}
}
prev.Next = tempNode;
tempNode.Next = current;
}
//Question-7 Given a list use sortedInsert method to sort the list.
public LinkedList InsertedSort(LinkedList head)
{
if (head == null) return null;
LinkedList current = head;
LinkedList temp=null;
while (current!=null)
{
SortedInsert (ref temp , current.Data);
current = current.Next;
}
return temp;
}
//Question-2, write a funcation which returns the data from a linked list given the index.
public int GetNth(LinkedList head, int index)
{
if (head == null) return -1; //invalid list
LinkedList current = head;
int count =0;
while (current !=null )
{
if (count == index) return current.Data;
count++;
current = current.Next;
}
return -1;
}
//Question-9 with slow/fast pointer implementation;
public void FrontBackSplitVer2(LinkedList head, ref LinkedList headA, ref LinkedList headB)
{
if (head == null) return;
if (head.Next == null)
{
headA = head;
headB = null;
return;
}
LinkedList fast = head.Next;
LinkedList slow = head;
while (fast!=null && fast.Next!=null )
{
fast = fast.Next;
if (fast != null)
{
fast = fast.Next;
slow = slow.Next;
}
}
headA = head;
headB = slow.Next;
slow.Next = null;
}
//Question -9 Front Back split - given a list split it into two lists in the case of odd length list the first half of the list will have a bigger size than the send half.
public void FrontBackSplit(LinkedList head, ref LinkedList headA, ref LinkedList headB)
{
if (head == null) return;
int count = Size(head);
int splitpoint = 0;
if (count%2==1) splitpoint = (count / 2);
else splitpoint =(count / 2)-1;
LinkedList current = head;
for (int i=0; i<splitpoint; i++)
{
current = current.Next;
}
headA = head;
headB = current.Next;
current.Next = null;
}
//Question-6 Sorted insert - write a function given a sorted list and given node, inserted in list in the right place.
public void SortedInsert(ref LinkedList head, int newData)
{
LinkedList tempNode = new LinkedList(newData);
LinkedList prev=head;
LinkedList current = head;
if (head == null)
{
head = tempNode;
return;
}
if(head!=null && head.Data>newData)
{
head = tempNode;
tempNode.Next = current;
return;
}
while (current!=null && current.Data<=newData)
{
prev = current;
current = current.Next;
}
prev.Next = tempNode;
tempNode.Next = current;
}
//Question-14 given two sorted list, write a function which will merge the two sorted list in to one
public void SortedMerge( ref LinkedList head, LinkedList headA, LinkedList headB)
{
if (headA == null && headB == null) return;
LinkedList currentA = headA;
LinkedList currentB = headB;
LinkedList current = head;
LinkedList tail = head;
while (currentA!=null && currentB!=null)
{
if (currentA.Data < currentB.Data)
{
if (head==null)
{
headA=currentA.Next;
head=currentA;
currentA.Next=tail;
tail=head;
currentA=headA;
}
else
{
headA=currentA.Next;
tail.Next=currentA;
tail=currentA;
currentA.Next=null;
currentA=headA;
}
}
else
{
if (head==null)
{
headB=currentB.Next;
head =currentB;
currentB.Next=tail;
tail=head;
currentB=headB;
}
else
{
headB=currentB.Next;
tail.Next=currentB;
tail=currentB;
currentB.Next=null;
currentB=headB;
}
}
}
if (currentA!=null)
{
tail.Next=headA;
}
else
{
tail.Next=headB;
}
}
//Question-4 write a function, given a non empty linked list, it will delte the head node and return the data value.
public int Pop(ref LinkedList head)
{
if (head == null) return -1;
LinkedList current = head;
int headValue = current.Data;
head = current.Next;
current = null;
return headValue;
}
public void Print(LinkedList head)
{
if (head==null) return;
string temp = string.Empty;
while (head!=null)
{
temp = string.Concat(temp,head.Data, ",");
head = head.Next;
}
Console.Write(temp.TrimEnd(','));
Console.WriteLine();
}
public void Push(ref LinkedList head, int newData)
{
LinkedList temp = new LinkedList(newData);
if (head == null) head = temp;
else
{
temp.Next = head;
head = temp;
}
}
//Question-3 write a function which deletes the list and deallocates all of the memory.
public void DeleteList(ref LinkedList head)
{
if (head == null) return;
LinkedList current = head;
LinkedList temp = head;
while (current!=null)
{
temp = current.Next;
current = null;
current = temp;
}
head = current;
}
public LinkedList(int data)
{
this.data = data;
this.next = null;
}
