Question

Using C programming Language,

2. Given a singly linked list (with a head pointer only) and an integer k, find the k^th node from the end of the linked list. Use a single path if possible.

Use the most efficient method, and state its run-time and space utilization in Big-O.

Answer 1

//please read all comments

#include <bits/stdc++.h>

using namespace std;

/* Node structure for linked list */

struct Node {

int data;

struct Node* next;

};

/* Function to get the kth node from the last*/

void printKthFromLast(struct Node* head, int k)

{

int len = 0, i;

struct Node* temp = head; //for iteration

// count the number of nodes

while (temp != NULL) {

temp = temp->next;

len++;

}

// check if k is more than list size

// more than length of the linked list

if (len < k)

return;

temp = head;

// Fetch the (len-k+1)th node from the start

for (i = 1; i < len - n + 1; i++)

temp = temp->next;

printf("%d",temp->data);

return;

}

//Function to add new node

void add(struct Node** head, int data)

{

struct Node* node = new Node();

// Put data

node->data = data;

node->next = (*head);

(*head) = node;

}

// Driver Code

int main()

{

// At very first time, list is empty

struct Node* head = NULL;

// create linked 1->12->90->29

add(&head, 29);

add(&head, 90);

add(&head, 12);

add(&head, 1);

printKthFromLast(head, 4);

return 0;

}

/* Output would be*/

1

/* Time complexity is O(n)

Linear

*/

Thanks ?