Help me in solving MAXISUM problem

help
,
1

My issue

i just learned the divide and conquer algo but i am not able to find the correct logic to solve this question can someone help

My code

def div_conq(n, k, a, b, i):
    if i == n:
        return 0
    
    if k == 0:
        return a[i] * b[i] + div_conq(n, k, a, b, i + 1)

    option1 = a[i] * b[i] + div_conq(n, k, a, b, i + 1)
    option2 = (a[i] + 1) * b[i] + div_conq(n, k - 1, a, b, i + 1)
    option3 = (a[i] - 1) * b[i] + div_conq(n, k - 1, a, b, i + 1)

    return max(option1, option2, option3)

for _ in range(int(input())):
    n, k = map(int, input().split())
    a = list(map(int, input().split()))
    b = list(map(int, input().split()))
    print(div_conq(n, k, a, b, 0))

Problem Link: maximize the sum Practice Coding Problem