Max Prefix

Easy

0/40

Average time to solve is 7m

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4 upvotes

Asked in company

Problem statement

You are given an array 'A' of length 'N'. You can perform the operation defined below any number of times (Possibly 0).

Choose 'l', 'r' (1 <= 'l' <= 'r' <='N') and reverse the subarray from 'l' to 'r'.

After that, Return the maximum possible sum of the prefix of this array of length 'K'.

For Example:-

Let 'N' = 5, 'K' = 3, 'A' = [4, 2, 1, 2, 2].
We can reverse the subarray from index 3 to 4 (1-based indexing).
Array becomes [4, 2, 2, 1, 2].
Our answer is 8.

Detailed explanation ( Input/output format, Notes, Images )

Input Format:-

First-line contains an integer 'T', which denotes the number of test cases.
For every test case:-
First-line contains two integers 'N' and 'K'.
Second-line contains 'N' space-separated integers, elements of array 'A'.

Output Format:-

For each test case, Return the maximum possible sum of the prefix of this array of length 'K'.

Note:-

You don’t need to print anything. Just implement the given function.

Constraints:-

1 <= 'T' <= 10
1 <= 'K' <= 'N' <= 10^5
1 <= 'A[i]' <= 10^3

The Sum of 'N' overall test cases does not exceed 10^5.
Time Limit: 1 sec

Sample Input 1:-

Sample Output 1:-

4
5

Explanation of sample input 1:-

First test case:-
We do not need to reverse any subarray.
Our answer is 4.

Second test case:-
We can reverse the subarray from index 1 to 3 (1-based indexing).
Array becomes [3, 2, 2].
Our answer is 5.

Sample Input 2:-

Sample Output 2:-

9
15

Console