Todo.txt

1) https://leetcode.com/problems/partition-to-k-equal-sum-subsets/

2) Asked by Airbnb : https://leetcode.com/problems/rotate-list/

Given a linked list and a positive integer k, rotate the list to the right by k places.
For example, given the linked list 7 -> 7 -> 3 -> 5 and k = 2, it should become 3 -> 5 -> 7 -> 7.
Given the linked list 1 -> 2 -> 3 -> 4 -> 5 and k = 3, it should become 3 -> 4 -> 5 -> 1 -> 2.

3) Asked by Amazon

Given a string, determine whether any permutation of it is a palindrome.
For example, carrace should return true, since it can be rearranged to form racecar, which is a palindrome. 
daily should return false, since there's no rearrangement that can form a palindrome.

4) https://www.geeksforgeeks.org/minimum-steps-reach-target-knight/

5) https://leetcode.com/problems/friend-circles/

6) https://leetcode.com/problems/max-chunks-to-make-sorted-ii/

7) Asked by Quora
   Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path.
   For example, given "/usr/bin/../bin/./scripts/../", return "/usr/bin/".

8) https://leetcode.com/discuss/interview-question/502496/google-onsite-substrings-that-dont-have-every-character-in-an-alphabet

9) https://leetcode.com/contest/biweekly-contest-19/problems/jump-game-iv/

10) LinkedIn: You are given a string consisting of the letters x and y, such as xyxxxyxyy. In addition, you have an operation called flip, which
 changes a single x to y or vice versa. Determine how many times you would need to apply this operation to ensure that all x's come before
  all y's. In the preceding example, it suffices to flip the second and sixth characters, so you should return 2.

11) Asked by Salesforce
    Write a program to merge two binary trees. Each node in the new tree should hold a value equal to the sum of the values 
    of the corresponding nodes of the input trees. If only one input tree has a node in a given position, the corresponding node
    in the new tree should match that input node.

12) Given an unsorted array, in which all elements are distinct, find a "peak" element in O(log N) time.
    An element is considered a peak if it is greater than both its left and right neighbors. It is guaranteed that the first 
    and last elements are lower than all others.

13) Asked by Snapchat
    Given a string of digits, generate all possible valid IP address combinations.
    IP addresses must follow the format A.B.C.D, where A, B, C, and D are numbers between 0 and 255. Zero-prefixed numbers, 
    such as 01 and 065, are not allowed, except for 0 itself. For example, given "2542540123", you should return 
    ['254.25.40.123', '254.254.0.123'].

14) Asked by Microsoft
    Given a string and a pattern, find the starting indices of all occurrences of the pattern in the string.
    For example, given the string "abracadabra" and the pattern "abr", you should return [0, 7].

15) Asked by Stripe

    Given a collection of intervals, find the minimum number of intervals you need to remove to make the rest of the intervals
    non-overlapping. Intervals can "touch", such as [0, 1] and [1, 2], but they won't be considered overlapping.
    For example, given the intervals (7, 9), (2, 4), (5, 8), return 1 as the last interval can be removed and the first two
    won't overlap. The intervals are not necessarily sorted in any order.

16) Asked by Facebook
    Given a circular array, compute its maximum subarray sum in O(n) time. A subarray can be empty, and in this case the sum is 0.
    For example, given [8, -1, 3, 4], return 15 as we choose the numbers 3, 4, and 8 where the 8 is obtained from wrapping around.
    Given [-4, 5, 1, 0], return 6 as we choose the numbers 5 and 1.

17)  Asked by Google

    You are given an array of nonnegative integers. Let's say you start at the beginning of the array and are trying to 
    advance to the end. You can advance at most, the number of steps that you're currently on. Determine whether you can
    get to the end of the array. For example, given the array [1, 3, 1, 2, 0, 1], we can go from indices 0 -> 1 -> 3 -> 5, 
    so return true. Given the array [1, 2, 1, 0, 0], we can't reach the end, so return false.

18) Asked by Dropbox
    Given a string s and a list of words words, where each word is the same length, find all starting indices of substrings in s 
    that is a concatenation of every word in words exactly once. For example, given s = "dogcatcatcodecatdog" and 
    words = ["cat", "dog"], return [0, 13], since "dogcat" starts at index 0 and "catdog" starts at index 13.
    Given s = "barfoobazbitbyte" and words = ["dog", "cat"], return [] since there are no substrings composed of "dog" and "cat" in s.

    The order of the indices does not matter.

19) Asked by Square

Given a list of words, return the shortest unique prefix of each word. For example, given the list:

* dog
* cat
* apple
* apricot
* fish

Return the list:

* d
* c
* app
* apr
* f

20) Asked by Facebook
Given a String and a target find the number of possibilities the target can be formed using all the digits in the string (same order, used only once) using only + and - operations.

Example: Given "13" and 2
return 1
because -1+3 = 2

21) Asked by Google
There's a faulty keyboard which types a space whenever key 'e' is hit.
Given a string which is the sentence typed using that keyboard and a dictionary of valid words, return all possible correct formation of the sentence.
Example:
Input: s = "I lik   to   xplor   univ rs ", dictionary  = {"like", "explore", "toe", "universe", "rse"}
Output:
["I like to explore universe",
"I like toe xplor  universe",
"I like to explore univ rse",
"I like toe xplor  univ rse"]
There are two spaces after "lik", "to" and before "univ" in the sentence indicating one is actual space and another one is resulted by hitting key 'e'.

22) Asked by Google
We can determine how "out of order" an array A is by counting the number of inversions it has. Two elements A[i] and A[j] form an inversion 
if A[i] > A[j] but i < j. That is, a smaller element appears after a larger element.
Given an array, count the number of inversions it has. Do this faster than O(N^2) time.
You may assume each element in the array is distinct.
For example, a sorted list has zero inversions. The array [2, 4, 1, 3, 5] has three inversions: (2, 1), (4, 1), and (4, 3). The array [5, 4, 3, 2, 1] has ten inversions: every distinct pair forms an inversion.

23)  Asked by Google

Given a list of integers S and a target number k, write a function that returns a subset of S that adds up to k. If such a subset cannot be made, 
then return null. Integers can appear more than once in the list. You may assume all numbers in the list are positive.

For example, given S = [12, 1, 61, 5, 9, 2] and k = 24, return [12, 9, 2, 1] since it sums up to 24.

24) Queue Reconstruction by Height


https://leetcode.com/problems/the-skyline-problem/
https://leetcode.com/problems/rotting-oranges/
https://leetcode.com/problems/leftmost-column-with-at-least-a-one/
https://leetcode.com/problems/integer-to-english-words/
https://leetcode.com/problems/nested-list-weight-sum/
https://leetcode.com/problems/continuous-subarray-sum/
https://leetcode.com/problems/palindrome-partitioning-iii/
https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/

https://leetcode.com/problems/combination-sum-ii/
https://leetcode.com/problems/alien-dictionary/
https://leetcode.com/discuss/interview-question/1137426/facebook-minimizing-permutations