Given a singly linked list and a number k, write a function to find the (n/k)-th element, where n is the number of elements in the list. We need to consider ceil value in case of decimals.
Examples:
Input : list = 1->2->3->4->5->6
k = 2
Output : 3
Since n = 6 and k = 2, we print (6/2)-th node
which is 3.
Input : list = 2->7->9->3->5
k = 3
Output : 7
Since n is 5 and k is 3, we print ceil(5/3)-th
node which is 2nd node, i.e., 7.- Take two pointers temp and fractionalNode and initialize them with null and head respectively.
- For every k jumps of the temp pointer, make one jump of the fractionalNode pointer.
Implementation:
C++
#include <bits/stdc++.h>
struct Node {
int data;
Node* next;
};
Node* newNode(int data)
{
Node* new_node = new Node;
new_node->data = data;
new_node->next = NULL;
return new_node;
}
Node* fractionalNodes(Node* head, int k)
{
if (k <= 0 || head == NULL)
return NULL;
Node* fractionalNode = NULL;
int i = 0;
for (Node* temp = head; temp != NULL; temp = temp->next) {
if (i % k == 0) {
if (fractionalNode == NULL)
fractionalNode = head;
else
fractionalNode = fractionalNode->next;
}
i++;
}
return fractionalNode;
}
void printList(Node* node)
{
while (node != NULL) {
printf("%d ", node->data);
node = node->next;
}
printf("\n");
}
int main(void)
{
Node* head = newNode(1);
head->next = newNode(2);
head->next->next = newNode(3);
head->next->next->next = newNode(4);
head->next->next->next->next = newNode(5);
int k = 2;
printf("List is ");
printList(head);
Node* answer = fractionalNodes(head, k);
printf("\nFractional node is ");
printf("%d\n", answer->data);
return 0;
}
|
Java
public class FractionalNodell
{
static class Node{
int data;
Node next;
Node (int data){
this.data = data;
}
}
static Node fractionalNodes(Node head, int k)
{
if (k <= 0 || head == null)
return null;
Node fractionalNode = null;
int i = 0;
for (Node temp = head; temp != null;
temp = temp.next){
if (i % k == 0){
if (fractionalNode == null)
fractionalNode = head;
else
fractionalNode = fractionalNode.next;
}
i++;
}
return fractionalNode;
}
static void printList(Node node)
{
while (node != null)
{
System.out.print(node.data+" ");
node = node.next;
}
System.out.println();
}
public static void main(String[] args) {
Node head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
int k =2;
System.out.print("List is ");
printList(head);
Node answer = fractionalNodes(head, k);
System.out.println("Fractional node is "+
answer.data);
}
}
|
Python3
import math
class Node:
def __init__(self, data):
self.data = data
self.next = None
def newNode(data):
new_node = Node(data)
new_node.data = data
new_node.next = None
return new_node
def fractionalNodes(head, k):
if (k <= 0 or head == None):
return None
fractionalNode = None
i = 0
temp = head
while (temp != None):
if (i % k == 0):
if (fractionalNode == None):
fractionalNode = head
else:
fractionalNode = fractionalNode.next
i = i + 1
temp = temp.next
return fractionalNode
def printList(node):
while (node != None):
print(node.data, end = ' ')
node = node.next
if __name__ == '__main__':
head = newNode(1)
head.next = newNode(2)
head.next.next = newNode(3)
head.next.next.next = newNode(4)
head.next.next.next.next = newNode(5)
k = 2
print("List is", end = ' ')
printList(head)
answer = fractionalNodes(head, k)
print("\nFractional node is", end = ' ')
print(answer.data)
|
C#
using System;
public class FractionalNodell
{
public class Node
{
public int data;
public Node next;
public Node (int data)
{
this.data = data;
}
}
static Node fractionalNodes(Node head, int k)
{
if (k <= 0 || head == null)
return null;
Node fractionalNode = null;
int i = 0;
for (Node temp = head; temp != null;
temp = temp.next)
{
if (i % k == 0)
{
if (fractionalNode == null)
fractionalNode = head;
else
fractionalNode = fractionalNode.next;
}
i++;
}
return fractionalNode;
}
static void printList(Node node)
{
while (node != null)
{
Console.Write(node.data+" ");
node = node.next;
}
Console.WriteLine();
}
public static void Main(String[] args)
{
Node head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
int k =2;
Console.Write("List is ");
printList(head);
Node answer = fractionalNodes(head, k);
Console.WriteLine("Fractional node is "+
answer.data);
}
}
|
Javascript
<script>
class Node {
constructor(val) {
this.data = val;
this.next = null;
}
}
function fractionalNodes(head , k) {
if (k <= 0 || head == null)
return null;
var fractionalNode = null;
var i = 0;
for (temp = head; temp != null; temp = temp.next) {
if (i % k == 0) {
if (fractionalNode == null)
fractionalNode = head;
else
fractionalNode = fractionalNode.next;
}
i++;
}
return fractionalNode;
}
function printList(node) {
while (node != null) {
document.write(node.data + " ");
node = node.next;
}
document.write();
}
var head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(4);
head.next.next.next.next = new Node(5);
var k = 2;
document.write("List is ");
printList(head);
var answer = fractionalNodes(head, k);
document.write("<br/>Fractional node is " + answer.data);
</script>
|
OutputList is 1 2 3 4 5
Fractional node is 3
Complexity Analysis
- Time Complexity: O(n)
- Space complexity: O(1)
This article is contributed by Prakriti Gupta. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.