700634. Modular Node
Modular Node
Slug: modular-node
Difficulty: Basic
Id: 700634
Topic Tags: Linked List, Modular Arithmetic, Data Structures, Algorithms
Company Tags: None
Summary
Given a linked list and an integer k, find the node that is k positions ahead in the circular linked list. The problem involves understanding modular arithmetic and how it applies to linked lists.
Detailed Explanation
The key concept here is modular arithmetic. Since we are dealing with a circular linked list, when we reach the end of the list, we can wrap around to the beginning of the list using modular arithmetic.
To solve this problem, we can traverse the linked list until we reach the node that is k positions ahead. We use modular arithmetic to keep track of our position in the list and ensure that we don't go past the end of the list.
Here's a step-by-step breakdown of the solution:
- Initialize a pointer
currentto the beginning of the linked list. - Initialize a variable
positionto 0, which represents our current position in the list. - Traverse the linked list until we reach the node that is
kpositions ahead:- While
positionis less thank, incrementpositionand movecurrentto the next node in the list. - When
positionequalsk, return the current node.
- While
The time complexity of this solution is O(n), where n is the number of nodes in the linked list. The space complexity is O(1), as we only use a constant amount of space to store our pointers and variables.
Optimized Solutions
Java
public Node findNode(Node head, int k) {
Node current = head;
int position = 0;
while (position < k) {
current = current.next;
position = (position + 1) % current.length();
}
return current;
}