Software Developer

You are given a string 'Str' consisting of 'N' lowercase Latin letters. You have to find the longest substring of the given string without repeating characters.

String ‘B’ is a substring of string ‘A’ if it can be obtained from ‘A’ by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.

For Example :

If the given input string is "aabc", then you should return "abc" as the longest substring without repeating characters.

Note :

If there are multiple substrings with the same length, then you should print the substring which comes earlier in the given string. 

For Example :

If the given input string is "abcda", here “abcd” and “bcda” can be the longest unique substring but “abcd” comes earlier in the given string. So we will print “abcd” as the longest unique substring.

You are given a string 'str' of lowercase alphabets and an integer 'k' .

Your task is to return the count all the possible substrings that have exactly 'k' distinct characters.

For example:

'str' = abcad and 'k' = 2. 

We can see that the substrings {ab, bc, ca, ad} are the only substrings with 2 distinct characters. 

Therefore, the answer will be 4.    

You are given an array 'A' of size 'N' and an integer 'K'.

The 'Pulse' of a subarray of 'A' is defined as the product of the number of even elements and the number of odd elements in that subarray.

Return the minimum possible length of a subarray having 'Pulse' greater than or equal to 'K'. If there does not exist any subarray having 'Pulse' greater than or equal to 'K', then return -1.

Note : Assume 0-based indexing.

A subarray is any contiguous part of an array.

For example:

Let 'N' = 5, 'K' = 4, 'A' = [2, 2, 2, 1, 1].
There exist only two subarrays, 'A[0…4]' and 'A[1…4]' having 'Pulse' greater than or equal to 'K'. 
'Pulse' of 'A[0…4]' is 6 and the length is 5.
'Pulse' of 'A[1…4]' is 4 and the length is 4.
 Since we have to minimize the length, therefore 4 will be our answer.