CareerCup

find a shortest string to cover all of a list of string,
For example, [aab, aabb, bc], should return aabbc,
because aab, aabb, bc are all the substring of aabbc

Given a linked list with next and random pointer, deepcopy the linked list and return new head.

Node {
char val,
Node next,
Node random }

A {
val: ’a’
next: D
random: G}

D {
val: ’d’
next: G
random: A}

G {
val: ’g’
next: null
random: D}


-----------
| |
| V
A -> D -> G -> null

-------------
| |
| V
A' -> D' -> G' -> null

Explain in detail about your favourite android api.

given 2 list of interval representing users online offline timestamp e.g (already sorted), find all intervals that both of users are online.

e.g A= [(3, 5), (7, 11)] B=[(2, 4), (9, 10)] --> [(3, 4), (9, 10)].

Facebook
-Phone: LC304 & longest arithmetic sequence. Return the sequence.

Given an array of integers and k, find the difference between the number of the strictly increasing number of subarrays (of size more than one) and the number of the strictly decreasing subarray in the window of size k. your method should be time and space efficent
example
int[] nums = {188930, 194123, 201345, 154243, 154243};
int k = 3;
Output
3, 0, -1
Explanation
For the first window of [188930, 194123, 201345], there are 3 increasing subranges ([188930, 194123, 201345], [188930, 194123], and [194123, 201345]) and 0 decreasing, so the answer is 3. For the second window of [194123, 201345, 154243], there is 1 increasing subrange and 1 decreasing, so the answer is 0. For the third window of [201345, 154243, 154243], there is 1 decreasing subrange and 0 increasing, so the answer is -1.
public int[] getdiff(int[] nums, int l){
}

There is an unordered interval stream, write a method, returns the total length that all intervals cover by now
class Interval{
 	int start;
	int end;
}
public List<Integer> countCoverLength(Iterator<Interval> stream){

}

‘.’Matches any single character,' * 'Matches any sequence of characters (including the empty sequence).
There are two input, one is string pattern, and the other is dictionary like dict = ["cat", "cats", "and", "sand", "dog"].
return a boolean: whether to find a dictionary in the pattern match the word
eg: dict = ["cat", "cats", "and", "sand", "dog"].
pattern = "* t", -> true (can match cat)
pattern = ".a *" -> true (can match cat, cats, can also match sand, because * can also express empty sequence)

How would you store and retrieve values in Memcache if the values are larger than the individual value size allowed by Memcache?

node {
node * left, * right;
}
Given a list of node to determine whether the node in the list can form a valid binary tree. several points of judgment
1. need to ensure that all left, right pointer point to the node inside list
2. no cycle
3. All node must be connected
Boolean isValidTree(List<Node> list){}

Given a matrix of N * M, given the coordinates (x, y) present in a matrix,
Find the number of paths that can reach (0, 0) from the (x, y) points with k steps (requires exactly k, k> = 0)
From each point you can go up, down, left and right in four directions.

For example, the following matrix:
----------
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
(x, y) = (1, 1), k = 2, the output is 2

Find all words [A-Z] in a dictionary (about 1M words) that are made of a subset (in any order) of the chars in the input parameter [A-Z].
ex: input "ACRAT" (10 to 20 chars, up to 30 worst case)
matching words: "A", "CAR", "ACA", "ART", "RAC".
non-matching words: "BAR", "AAA"

follow up : the input is a list of words. Return a list of words that each
list is formed by exactly the characters in the input list.
For example: two lists {“DEBIT”, “CARD”} and{“BAD”, “CREDIT”}
are formed by the same exact group of characters.

Given a sorted list of integers, square the elements and give the output in sorted order.

Find the distance between the farthest two elements in a binary tree.

Given a string separated by a space like "123456 abc+efg" determine
the solution by mapping integers to letters like a:1, b:2, c:3, d:4, e:5, f:6.
The only operations allowed were + or -. So the calculated solution
that made the tests pass was 123+456 = 579.

How many subsets of a given array sum to zero?

Given numbers 1 through 52, take 5 unique numbers and determine
if the number 42 can be made using any combination of addition (+),
subtraction (-), multiplication (*), and division (/) on those 5 numbers

/* Intersection of two sorted interval lists, A=[(1,2), (5,7)..]
B=[(2,6)...] return [(5,6)..] */

import java.util.*;
class Interval{
    int start;
    int end;
    public Interval(int start, int end){
        this.start = start;
        this.end = end;
    }
}
class Solution {
    
    public List<Interval> Intersection(Interval[] i1, Interval[] i2) {}

* Given a string on length N. You can swap only the adjacent elements
and each element can be swapped atmost once.
Find the no of permutations of the string that can be generated after
performing the swaps as mentioned.
Ex –
string – “12345”
Ans = 8
Explanations- (All the permutations)
12345
21345
13245
12435
12354
21435
13254
21354

Given an array of n positive integers, find the number of subarrays
such that product of the elements of those subarrays are less than k.
For eg. Arr= {2, 3, 6} k=10
No of such subarrays= 4

Print the levels of a binary tree in reverse order using stack and recursion

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).

For example:
Given binary tree
    3
   / \
  9  20
    /  \
   15   7
return its bottom-up level order traversal as:
[
  [15,7],
  [9,20],
  [3]
]

public List<List<Integer>> levelOrderBottom(TreeNode root) {
}

given an array, find whether there exists 3 elements a,b,c in it such that a+b=c using efficient method.

You are provided a BST, which is corrupted. One of the nodes in it has 2 parents.
Let’s say those are parent 1 and parent 2. It is ensured that none
of these parents will be the ancestor of the other. Identify the node,
and remove the link of the wrong parent.

given an array of strings and characters, make the largest string possible.
The resultant string should be a combination of the strings given in the array.
The given array
of characters may contain repeated elements.
Example – Given char array – {a,a,b,c,d,d,e,c} and given strings
– {abba, aabc, de, cde} the
ans is aabccde

Given an adjacency matrix of a directed graph, find the number of cycles in the graph

Given K sorted (ascending) arrays. Write an iterator class that iterate over the arrays and returns the next element. Duplicate are allowed. What is the complexity to iterate the entire arrays? what is the complexity for each iteration?

Example:

arr1 = {1,2,3,4,7,9}
arr2 = {3,5,6,8,10}

The iterator should return:

1,2,3,3,4,5,6,7,8,9,10

Extension:
Don't return duplicates, so the above iterator should return:

1,2,3,4,5,6,7,8,9,10

Given a binary tree that complies to the following rule:
The parent node value is always the the result of the AND operator of its children values.

You modify one of the LEAF nodes value (e.g. if it was 1 it is now 0). Write a function that fixes the tree
so it complies with the above rule.

//
//        0                                 1
//      /   \                             /   \
//    1      0            =====>         1     1
//   / \    / \                         / \   / \
//  1   1  0   1                       1   1 1   1
//
// The parent node value is always children value's LOGICAL AND
//   &
//

Given an array of integers, return the index of the max value in this array.

Note:
If the max value appears more than once, the function should return one the indexes, but make it so that the next call will return different index.

Important: you are not allowed to store state between calls

Example: given this input array

//   0     -1     6    4   5    6      6
//                |             |      |
//               2,1/3       5,1/3     6,1/3

Function signature:

int getIndex(const std::vector<int>& numbers);

Example output:

2
5
6
5
2

Extension:
What if you knew how many times the max value appears in the array, can you improve the function performance?

So using the given example array, the function signature is now:

int getIndex(const std::vector<int>& numbers, int maxCount);

Given an array of n * m matrix, and a moving matrix window (size k * k), move the window from top left to bottom right at each iteration, find the median number inside the window at each moving
Can you do it better than brutal force method?
void getMedian(int[][] matrix,  int k){
	print median
}
For matrix
[
  [1, 5, 3],
  [3, 2, 1],
  [4, 1, 9],
]
The moving window size k = 2. 
 
At first the window is at the start of the array like this
[
  [|1, 5|, 3],
  [|3, 2|, 1],
  [4, 1, 9],
]
,get the median (2 + 3) / 2 = 2.5;
then the window move one step forward.
[
  [1, |5, 3|],
  [3, |2, 1|],
  [4, 1, 9],
]
,get the median (2 + 3) / 2 = 2.5
then the window move one step forward again.
[
  [1, 5, 3],
  [|3, 2|, 1],
  [|4, 1|, 9],
]
,get the median (2 + 3) / 2 = 2.5
then the window move one step forward again.
[
  [1, 5, 3],
  [3, |2, 1|],
  [4, |1, 9|],
]
,get the median (1 + 2) / 2 = 1.5

We are planning an orienteering game.
The aim of this game is to arrive at the goal (G) from the start (S) with the shortest distance.
However, the players have to pass all the checkpoints (@) on the map.
An orienteering map is to be given in the following format.
########
#@....G#
##.##@##
#..@..S#
#@.....#
########
In this problem, an orienteering map is to be given.
Calculate the minimum distance from the start to the goal with passing all the checkpoints.
Specification
* A map consists of 5 characters as following.
You can assume that the map does not contain any invalid characters and
the map has exactly one start symbol 'S' and exactly one goal symbol 'G'.
* 'S' means the orienteering start.
* 'G' means the orienteering goal.
* '@' means an orienteering checkpoint.
* '.' means an opened-block that players can pass.
* '#' means a closed-block that players cannot pass.
* It is allowed to move only by one step vertically or horizontally (up, down, left, or right) to the
next block.
Other types of movements, such as moving diagonally (left up, right up, left down and right down)
and skipping one or more blocks, are NOT permitted.
* You MUST NOT get out of the map.
* Distance is to be defined as the number of movements to the different blocks.
* You CAN pass opened-blocks, checkpoints, the start, and the goal more than once if necessary.
* You can assume that parameters satisfy following conditions.
* 1 <= width <= 100
* 1 <= height <= 100
* The maximum number of checkpoints is 18.