Lecture 139:-  Print Kth Node From The End

To print the kth node from the end of a singly linked list, you can use the two-pointer technique. Here's the approach:

1. Initialize two pointers, first and second, pointing to the head of the linked list.
2. Move the first pointer k nodes ahead.
3. Then, move both first and second pointers simultaneously until first reaches the end of the list.
4. At this point, the second pointer will be pointing to the kth node from the end.

Here's a C++ implementation of this approach:

cppCopy code

#include <iostream> class Node { public: int data; Node* next; Node(int value) : data(value), next(nullptr) {} }; Node* kthNodeFromEnd(Node* head, int k) { if (head == nullptr || k <= 0) { return nullptr; } Node* first = head; Node* second = head; // Move first pointer k nodes ahead for (int i = 0; i < k; ++i) { if (first == nullptr) { return nullptr; // Handle case where k is greater than the list length } first = first->next; } // Move both pointers until first reaches the end while (first != nullptr) { first = first->next; second = second->next; } return second; // Second points to the kth node from the end } int main() { 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; // Find the 2nd node from the end Node* kthNode = kthNodeFromEnd(head, k); if (kthNode) { std::cout << "Kth Node from the end: " << kthNode->data << std::endl; } else { std::cout << "Invalid value of k or empty list." << std::endl; } return 0; }

In this example, we're finding the kth node from the end of a linked list. The function kthNodeFromEnd implements the two-pointer approach as described earlier. Make sure to handle edge cases such as an empty list or an invalid value of k.