you should return the answer mod 1e9+7

n = 0 means the null matrix. The determinant of the null matrix is 0. If k is also 0, the determinant of the null matrix to the power of zero is the same as 0^0. I think this does not make sense at all.

got it

fixed

I will leave it as is and close this issue now.

Your task is to calculate the expected value of a randomly selected element from this matrix that is the average value that you would anticipate following a large number of trials where each element has an equal likelihood of being selected.

I hope I made the wording clearer

I added one example with 5 steps.

It should be clear that in order to get from step 1 to 5, there should be at least 4 instructions.

from say step 2 to 5 or 1 to 4, there should be at least 3 instructions.

from 1 to 3, 2 to 4, 3 to 5, 2 instructions.

you get my point? The graphs that I made have multiple examples within that are "subarrays" of the example with most instructions.