0237. Delete Node in a Linked List.js

// Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.
//
// Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value 3, the linked list should become 1 -> 2 -> 4 after calling your function.

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *   this.val = val;
 *   this.next = null;
 * }
 */

/**
 * @param {ListNode} node
 * @return {void} Do not return anything, modify node in-place instead.
 */

// Since we do not have access to the node before the one we want to delete, we cannot modify the next pointer of that node in any way.
// Instead, we have to replace the value of the node we want to delete with the value in the node after it, and then delete the node after it.
// Because we know that the node we want to delete is not the tail of the list, we can guarantee that this approach is possible.
const deleteNode = (node) => {
  node.val = node.next.val;
  node.next = node.next.next;
};