SDE - 1

You are given an array of ‘N’ distinct integers and an integer ‘X’ representing the target sum. You have to tell the minimum number of elements you have to take to reach the target sum ‘X’.

Note:

You have an infinite number of elements of each type.

For example

If N=3 and X=7 and array elements are [1,2,3]. 
Way 1 - You can take 4 elements  [2, 2, 2, 1] as 2 + 2 + 2 + 1 = 7.
Way 2 - You can take 3 elements  [3, 3, 1] as 3 + 3 + 1 = 7.
Here, you can see in Way 2 we have used 3 coins to reach the target sum of 7.
Hence the output is 3.

You are the HR of the Ninja team and planning to hire ‘M’ candidates out of ‘N’ candidates to form a paid group. The candidates have been evaluated on the basis of their skills and have been asked for their minimum salary expectations. So, you are given two arrays, ‘SKILL’ and ‘EXPECTED_SALARY’, where ‘SKILL[i]’ and ‘EXPECTED_SALARY[i]’ represent the skill and minimum salary expectation of ‘i-th’ candidate, respectively. You have to consider the following two rules for hiring a group of ‘M’ candidates:

1) Every candidate in the paid group should be paid in the ratio of their skill compared to other candidates in the paid group.
2) The minimum salary expectation of every candidate in the paid group should be fulfilled.

You have to return the minimum amount of money required to hire ‘M’ candidates as per the above-mentioned rules.

Note:

Answers which are within the range 10^-6 of the correct answer will be considered correct.

Given a sorted array of keys of BST and an array of frequency counts of each key in the same order as in the given inorder traversal. The frequency of an element is the number of searches made to that element. Construct a binary search tree from the given keys such that the total cost of all the searches is minimum.

Cost of searching a key is its frequency multiplied by its level number in the BST.

A binary search tree (BST), also called an ordered or sorted binary tree, is a rooted binary tree whose internal nodes each store a key greater than all the keys in the node's left subtree and less than those in its right subtree.

For example:

Input keys = [ 1, 3, 5 ] 
Frequency = [ 3, 10, 7 ] 

All the unique BST possible from the given keys are: 

Among all these possible BST, the minimum cost is obtained from the below BST: 

Cost = 1 * (freq of 3) + 2 * (freq of 1) + 2 * (freq of 5) = 30 
where 1 is the level of node 3, 2 is the level of the node 1 and node 5. 

Given two strings, 'S' and 'T' with lengths 'M' and 'N', find the length of the 'Longest Common Subsequence'.

For a string 'str'(per se) of length K, the subsequences are the strings containing characters in the same relative order as they are present in 'str,' but not necessarily contiguous. Subsequences contain all the strings of length varying from 0 to K.

Example :

Subsequences of string "abc" are:  ""(empty string), a, b, c, ab, bc, ac, abc.

Design a service which will count how many times a video was refreshed by user.
Was asked DB schema
Core logic
Data structures to be used
Optimization

Design splitwise app
Only approach was asked not the full design
Basic managerial questions about deadline and work ethics.