Breaking News: Grepper is joining You.com. Read the official announcement!

Give an algorithm for finding the ith-to-last node in a singly linked list in which the last node is indicated by a null next reference.

Famous Fish answered on October 2, 2021 Popularity 5/10 Helpfulness 3/10

answer Give an algorithm for finding the ith-to-last node in a singly linked list in which the last node is indicated by a null next reference.

Give an algorithm for finding the ith-to-last node in a singly linked list in which the last node is indicated by a null next reference.

Comment

LinkedListNode nthToLast(LinkedListNode head, int n) {
  if (head == null || n < 1) {
    return null;
  }

  LinkedListNode p1 = head;
  LinkedListNode p2 = head;

  for (int j = 0; j < n - 1; ++j) { // skip n-1 steps ahead
    if (p2 == null) {
      return null; // not found since list size < n
    }
    p2 = p2.next;
  }

  while (p2.next != null) {
    p1 = p1.next;
    p2 = p2.next;
  }

  return p1;
}

Popularity 5/10 Helpfulness 3/10 Language cpp

Source: stackoverflow.com

Tags: algorithm c++ linked-list next null

Link to this answer
Share Copy Link