Min Product Array

The task is to find the minimum sum of Products of two arrays of the same size, given that k modifications are allowed on the first array. In each modification, one array element of the first array can either be increased or decreased by 2. 

Note- the product sum is Summation (A[i]*B[i]) for all i from 1 to n where n is the size of both arrays 

Input Format: 

1. First line of the input contains n and k delimited by whitespace
2. Second line contains the Array A (modifiable array) with its values delimited by spaces
3. Third line contains the Array B (non-modifiable array) with its values delimited by spaces

Output Format: 

1. Output the minimum sum of products of the two arrays 

Constraints:

1. 1 = N = 10^5
2. 0 = |A[i]|, |B[i]| = 10^5
3. 0 = K = 10^9

Explanations:

Explanation for sample 1: 

Here total numbers are 3 and total modifications allowed are 5. So we modified A[2], which is -3 and increased it by 10 (as 5 modifications are allowed). Now final sum will be
(1 * -2) + (2 * 3) + (7 * -5)
-2 + 6 – 35
-31

-31 is our final answer.

Explanation for sample 2: 

Here total numbers are 5 and total modifications allowed are 3. So we modified A[1], which is 3 and decreased it by 6 (as 3 modifications are allowed).
Now final sum will be
(2 * 3) + (-3 * 4) + (4 * 2) + (5 * 3) + (4 * 2)
6 – 12 + 8 + 15 + 8
25

25 is our final answer.