237__easy__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.

  Given linked list -- head = [4,5,1,9], which looks like following:

  Example 1:

  Input: head = [4,5,1,9], node = 5
  Output: [4,1,9]
  Explanation: You are given the second node with value 5, the linked list should become 4 -> 1 -> 9 after calling your function.
  Example 2:

  Input: head = [4,5,1,9], node = 1
  Output: [4,5,9]
  Explanation: You are given the third node with value 1, the linked list should become 4 -> 5 -> 9 after calling your function.


  Note:

  The linked list will have at least two elements.
  All of the nodes' values will be unique.
  The given node will not be the tail and it will always be a valid node of the linked list.
  Do not return anything from your function.

 */

/**
 *
 * O(n) time
 * O(1) space
 *
 * 20m (10sec next time...)
 */
var deleteNode = function(node) {
  // very tricky but interesting!
  node.val = node.next.val;
  node.next = node.next.next;
};