private void button7_Click(object sender, EventArgs e)
{
//http://www.jusfortechies.com/java/core-java/deepcopy_and_shallowcopy.php
RandomNode node1 = new RandomNode(1);
RandomNode node2 = new RandomNode(2);
RandomNode node3 = new RandomNode(3);
RandomNode node4 = new RandomNode(4);
node1.Next = node2;
node2.Next = node3;
node3.Next = node4;
//set random pointers
node1.Random = node3;
node2.Random = node4;
node3.Random = node4;
node4.Random = node1;
//Now we created linkedlist with next and random pointer..
RandomNode duplicate = deepCopy(node1);
this.textBox8.Text = NodeHelper.GetStringByRandomNode(duplicate);
}
private void button6_Click(object sender, EventArgs e)
{
//http://rajpal.x10.mx/copy-a-linked-list-with-next-and-random-pointer/
RandomNode node1 = new RandomNode(1);
RandomNode node2 = new RandomNode(2);
RandomNode node3 = new RandomNode(3);
RandomNode node4 = new RandomNode(4);
node1.Next = node2;
node2.Next = node3;
node3.Next = node4;
//set random pointers
node1.Random = node3;
node2.Random = node4;
node3.Random = node4;
node4.Random = node1;
//Now we created linkedlist with next and random pointer..
RandomNode duplicate = DuplicateLinkedListWithRandomNode(node1);
this.textBox8.Text = NodeHelper.GetStringByRandomNode(duplicate);
}
public static string GetStringByRandomNode(RandomNode head)
{
StringBuilder sb = new StringBuilder();
RandomNode runner = new RandomNode();
runner = head;
while (runner != null)
{
sb.Append(runner.Data.ToString()).Append(",");
runner = runner.Next;
}
return(sb.ToString());
}
private RandomNode deepCopy(RandomNode original)
{
// We use the following map to associate newly created instances
// of RandomNode with the instances of RandomNode in the original list
Hashtable map = new Hashtable();
// We scan the original list and for each RandomNode x we create a new
// RandomNode y whose data is a copy of x's data, then we store the
// couple (x,y) in map using x as a key. Note that during this
// scan we set y.next and y.random to null: we'll fix them in
// the next scan
RandomNode x = original;
while (x != null)
{
RandomNode y = new RandomNode(x.Data);
y.Next = null;
y.Random = null;
map.Add(x, y);
x = x.Next;
}
// Now for each RandomNode x in the original list we have a copy y
// stored in our map. We scan again the original list and
// we set the pointers buildings the new list
x = original;
while (x != null)
{
// we get the node y corresponding to x from the map
RandomNode y = (RandomNode)map[x];
// let x' = x.next; y' = map.get(x') is the new node
// corresponding to x'; so we can set y.next = y'
y.Next = (RandomNode)map[x.Next];
// let x'' = x.random; y'' = map.get(x'') is the new
// node corresponding to x''; so we can set y.random = y''
y.Random = (RandomNode)map[x.Random];
x = x.Next;
}
// finally we return the head of the new list, that is the RandomNode y
// in the map corresponding to the RandomNode original
return((RandomNode)map[original]);
}
// http://www.geeksforgeeks.org/clone-linked-list-next-random-pointer-o1-space/
public RandomNode DuplicateLinkedListWithRandomNode(RandomNode originalhead)
{
RandomNode duplicatehead = null;
RandomNode originalrunner, duplicaterunner, tempnext, tempnew;
//Iterate through the original and create a duplicate node and place it between original and next
//eg: Input A, B, C
// A a B b C c
originalrunner = originalhead;
while (originalrunner != null)
{
//store the next ..be safe for overwriting
tempnext = originalrunner.Next;
//create a new node everytime
tempnew = new RandomNode(originalrunner.Data);
tempnew.Next = originalrunner.Next;
tempnew.Random = null; //don't set the next
//set the new next to the original
originalrunner.Next = tempnew;
//we already incremented this
originalrunner = tempnext;
}
//At the end of this will loop we will have A, a, B, b, C, c
//Now copy the arbitrary link in this fashion original->next->random = original->random->next;
//This works because original->next is nothing but copy of original and Original->random->next is nothing but copy of random.
originalrunner = originalhead;
while (originalrunner != null)
{
//here original.next will be the copy of the orignal node.. orignal.random.next will be the copy of random
originalrunner.Next.Random = originalrunner.Random.Next;
//move two step to get only the orignla
originalrunner = originalrunner.Next.Next;
}
//At the end of loop both orignal and copy will have same random pointer
//restore back the orignal next property
originalrunner = originalhead;
//set duplicate header
duplicatehead = originalrunner.Next;
duplicaterunner = duplicatehead;
while (originalrunner != null && duplicaterunner != null)
{
//set the correct orignal
originalrunner.Next = originalrunner.Next.Next;
//this is for iteration
originalrunner = originalrunner.Next;
if (duplicaterunner.Next != null)
{
duplicaterunner.Next = duplicaterunner.Next.Next;
duplicaterunner = duplicaterunner.Next;
}
}
//at the end of duplicate is copied and orignal is restored
return(duplicatehead);
}
