Senior Software Engineer

Given an array of integers of size ‘N’ and a positive integer ‘K’. Return the number of non-empty subarrays whose sum is divisible by K.

A subarray is a contiguous subset of an array.

For Example :

Consider an array of size four. The elements of the array are { -4, 5, 6, 1}. 
The value of K is 4. 
The subarrays whose sum is divisible by 4 are as  follows:
[ -4 ] 
[-4, 5, 6, 1] 
[ 5, 6, 1] 
Hence, there are three subarrays whose sum is divisible by 4. 

You are given a string ‘S’, you need to find the length of the longest substring that contains at most two distinct characters.

Note:

A string ‘B’ is a substring of a string ‘A’ if ‘B’ that can be obtained by deletion of, several characters(possibly none) from the start of ‘A’ and several characters(possibly none) from the end of ‘A’. 

Follow up :

Can you try to solve this problem in O(N) time and O(1) space.

Example :

If ‘S’ = “ninninja”

Then, “ninnin” is the longest substring that contains at most two distinct characters. We will print the length of this substring which is equal to 6.

You have been given stock values/prices for N number of days. Every i-th day signifies the price of a stock on that day. Your task is to find the maximum profit which you can make by buying and selling the stocks.

 Note :

You may make as many transactions as you want but can not have more than one transaction at a time i.e, if you have the stock, you need to sell it first, and then only you can buy it again.

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Ninja and his friend are playing a game of subarrays. They have an array ‘NUMS’ of length ‘N’. Ninja’s friend gives him an arbitrary integer ‘K’ and asks him to find the length of the longest subarray in which the sum of elements is equal to ‘K’.

Ninjas asks for your help to win this game. Find the length of the longest subarray in which the sum of elements is equal to ‘K’.

If there is no subarray whose sum is ‘K’ then you should return 0.

Example:

Input: ‘N’ = 5,  ‘K’ = 4, ‘NUMS’ = [ 1, 2, 1, 0, 1 ]

Output: 4

There are two subarrays with sum = 4, [1, 2, 1] and [2, 1, 0, 1]. Hence the length of the longest subarray with sum = 4 is 4.