Create absolute list sorting in LL

absolute list sorting in LL

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+/*Sort linked list which is already sorted on absolute values
+Difficulty Level : Medium
+Last Updated : 13 May, 2021
+Given a linked list that is sorted based on absolute values. Sort the list based on actual values.
+Examples:
+
+
+Input :  1 -> -10
+output: -10 -> 1
+
+Input : 1 -> -2 -> -3 -> 4 -> -5
+output: -5 -> -3 -> -2 -> 1 -> 4
+
+Input : -5 -> -10
+Output: -10 -> -5
+
+Input : 5 -> 10
+output: 5 -> 10
+*/
+
+
+// C++ program to sort a linked list, already
+// sorted by absolute values
+#include <bits/stdc++.h>
+using namespace std;
+
+// Linked List Node
+struct Node
+{
+	Node* next;
+	int data;
+};
+
+// Utility function to insert a node at the
+// beginning
+void push(Node** head, int data)
+{
+	Node* newNode = new Node;
+	newNode->next = (*head);
+	newNode->data = data;
+	(*head) = newNode;
+}
+
+// Utility function to print a linked list
+void printList(Node* head)
+{
+	while (head != NULL)
+	{
+		cout << head->data;
+		if (head->next != NULL)
+			cout << " -> ";
+		head = head->next;
+	}
+	cout<<endl;
+}
+
+// To sort a linked list by actual values.
+// The list is assumed to be sorted by absolute
+// values.
+void sortList(Node** head)
+{
+	// Initialize previous and current nodes
+	Node* prev = (*head);
+	Node* curr = (*head)->next;
+
+	// Traverse list
+	while (curr != NULL)
+	{
+		// If curr is smaller than prev, then
+		// it must be moved to head
+		if (curr->data < prev->data)
+		{
+			// Detach curr from linked list
+			prev->next = curr->next;
+
+			// Move current node to beginning
+			curr->next = (*head);
+			(*head) = curr;
+
+			// Update current
+			curr = prev;
+		}
+
+		// Nothing to do if current element
+		// is at right place
+		else
+			prev = curr;
+
+		// Move current
+		curr = curr->next;
+	}
+}
+
+// Driver code
+int main()
+{
+	Node* head = NULL;
+	push(&head, -5);
+	push(&head, 5);
+	push(&head, 4);
+	push(&head, 3);
+	push(&head, -2);
+	push(&head, 1);
+	push(&head, 0);
+
+	cout << "Original list :\n";
+	printList(head);
+
+	sortList(&head);
+
+	cout << "\nSorted list :\n";
+	printList(head);
+
+	return 0;
+}
+