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MergeSortlinkedList.java
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MergeSortlinkedList.java
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public class MergeSortlinkedList {
node head = null;
// node a, b;
static class node {
int val;
node next;
public node(int val)
{
this.val = val;
}
}
node sortedMerge(node a, node b)
{
node result = null;
if (a == null)
return b;
if (b == null)
return a;
if (a.val <= b.val) {
result = a;
result.next = sortedMerge(a.next, b);
}
else {
result = b;
result.next = sortedMerge(a, b.next);
}
return result;
}
node mergeSort(node h)
{
// Base case : if head is null
if (h == null || h.next == null) {
return h;
}
// get the middle of the list
node middle = getMiddle(h);
node nextofmiddle = middle.next;
// set the next of middle node to null
middle.next = null;
// Apply mergeSort on left list
node left = mergeSort(h);
// Apply mergeSort on right list
node right = mergeSort(nextofmiddle);
// Merge the left and right lists
node sortedlist = sortedMerge(left, right);
return sortedlist;
}
// Utility function to get the middle of the linked list
public static node getMiddle(node head)
{
if (head == null)
return head;
node slow = head, fast = head;
while (fast.next != null && fast.next.next != null) {
slow = slow.next;
fast = fast.next.next;
}
return slow;
}
void push(int new_data)
{
}
// Utility function to print the linked list
void printList(node headref)
{
while (headref != null) {
System.out.print(headref.val + " ");
headref = headref.next;
}
}
public static void main(String[] args)
{
linkedList li = new linkedList();
li.push(15);
li.push(10);
li.push(5);
li.push(20);
li.push(3);
li.push(2);
// Apply merge Sort
li.head = li.mergeSort(li.head);
System.out.print("\n Sorted Linked List is: \n");
li.printList(li.head);
}
}