AlexeiDarmin

/*
  Given two (singly) linked lists, determine if the two lists intersect. Return the intersecting node. 
  Note that the intersection is defined based on reference not value. That is, if the kth node of the first 
  linked list is the exact same node (by reference) as the jth node of the second linked list, then they are 
  intersecting.
*/
function getIntersection(h1: Node, h2: Node) {
  const nodes1 = getNodesMap(h1)
  const nodes2 = getNodesMap(h2)

AlexeiDarmin

function isPalindrome(head: Node): boolean {
  if (!head) return true

  let str = [head.data]
  let node = head
  while(node.next) {
    node = node.next
    str.push(node.data)
  }

AlexeiDarmin

/*
You have two numbers represented by a linked list, where each node contains a single
digit. The digits are stored in reverse order, such that the 1s digit is at the head of the list. Write a 
function that adds the two numbers and returns the sum as a linked list.

input: (7 -> 1 -> 6) + (5 -> 9 -> 2). That is 617 + 295
output: 2 -> 9 -> 1. That is 912

Also write a solution for the forward order of digits

AlexeiDarmin

{"lastUpload":"2021-05-16T15:10:15.000Z","extensionVersion":"v3.4.3"}

AlexeiDarmin

function deleteSomeNode(node: Node) {
  if (!node) {
    return
  }
  if (!node.next) {
    node = undefined
  }

  if (node.next) {

AlexeiDarmin

function returnKthToLast(head: Node, k: number): Node | null {
  let delta = 0
  let node = head
  
  while (delta < k) {
    node = node.next
    ++delta
    if (!node) {
      return null

AlexeiDarmin

function deleteDuplicates(head: Node): Node {
  const occurredVals = new Map()
  let node = head
  occurredVals.set(node.data, true)
  while (node.next != null) {
    if (occurredVals.get(node.next.data) === true) {
      node.next = node.next.next 
    } else {
      occurredVals.set(node.next.data, true)

AlexeiDarmin

// If an element in an NxM matrix is zero, then every element in that row and column should be zero
function zeroOutMatrix(m: number[][]): number[][] {
  const zeroedRows = new Map()
  const zeroedCols = new Map()

  for (let r = 0; r < m.length; ++r) {
    for (let c = 0; c < m[r].length; c++){
      if (m[r][c] === 0) {
        zeroedCols.set(c, true)
        zeroedRows.set(r, true)

AlexeiDarmin

/*
  Rotate a NxN matrix by 90 degrees in place where each pixel in the matrix is 4 bytes.
*/

/* example call: 
    rotateMatrix(sanitizeData([
      [1,2,3],
      [8,9,4],
      [7,6,5]
    ]))

AlexeiDarmin

/*
  Assume you have a method called isSubstring() which checks if one word is a subtring of another.
  Given two strings, s1 and s2, write code to check if s2 is a rotation of s1 using only one call to
  isSubstring(). Eg "waterbottle is a rotation of erbottlewat"
*/
function checkSubstr(s1: string, s2: string): boolean {
  if (s1.length !== s2.length) {
    return false
  }
  const rotationByIndex = new Map()