human
I found an interesting problem on https://codeforces.com/problemset/problem/1280/F:
You are an intergalactic surgeon and you have an alien patient. For the purposes of this problem, we can and we will model this patient's body using a $2 \times (2k + 1)$ rectangular grid. The alien has $4k + 1$ distinct organs, numbered $1$ to $4k + 1$.

In healthy such aliens, the organs are arranged in a particular way. For example, here is how the organs of a healthy such alien would be positioned, when viewed from the top, for $k = 4$: [Image] 

Here, the E represents empty space. 

In general, the first row contains organs $1$ to $2k + 1$ (in that order from left to right), and the second row contains organs $2k + 2$ to $4k + 1$ (in that order from left to right) and then empty space right after. 

Your patient's organs are complete, and inside their body, but they somehow got shuffled around! Your job, as an intergalactic surgeon, is to put everything back in its correct position. All organs of the alien must be in its body during the entire procedure. This means that at any point during the procedure, there is exactly one cell (in the grid) that is empty. In addition, you can only move organs around by doing one of the following things:  You can switch the positions of the empty space E with any organ to its immediate left or to its immediate right (if they exist). In reality, you do this by sliding the organ in question to the empty space.
 You can switch the positions of the empty space E with any organ to its immediate top or its immediate bottom (if they exist) only if the empty space is on the leftmost column, rightmost column or in the centermost column. Again, you do this by sliding the organ in question to the empty space. 

Your job is to figure out a sequence of moves you must do during the surgical procedure in order to place back all $4k + 1$ internal organs of your patient in the correct cells. If it is impossible to do so, you must say so.

-----Input-----

The first line of input contains a single integer $t$ ($1 \le t \le 4$) denoting the number of test cases. The next lines contain...

I tried it in Python, but could not do it. Can you solve it?

Can you provide a the Python program you requested?
assistant
#Here is the Python program you requested.

def flatten(grid):
    k = len(grid[0]) // 2
    seek = list(range(2*k + 2)) + list(range(2*k + 2, 4*k + 2))[::-1]
    return [seek[v] for v in grid[0] + grid[1][::-1] if v]

def solve(grid):
    grid = list(map(list, grid))
    k = len(grid[0]) // 2
    flat = flatten(grid)

    m = {
        'L': 'l'*2*k + 'u' + 'r'*2*k + 'd',
        'R': 'u' + 'l'*2*k + 'd' + 'r'*2*k,
        'C': 'l'*k + 'u' + 'r'*k + 'd',
        'D': 'CC' + 'R'*(2*k + 1) + 'CC' + 'R'*(2*k + 2),
        'F': 'R'*(k - 1) + 'DD' + 'R'*(2*k + 1) + 'D' + 'L'*2*k + 'DD' + 'L'*k,
        'G': 'FF',
    }

    [(i, j)] = [(i, j) for i in range(2) for j in range(2*k + 1) if grid[i][j] == 0]
    st = 'r'*(2*k - j) + 'd'*(1 - i)

    for v in range(2, 4*k + 2):
        ct = flat.index(v)

        if ct >= 2:
            st += 'L'*(ct - 2) + 'GR'*(ct - 2) + 'G'
            flat = flat[ct - 1: ct + 1] + flat[:ct - 1] + flat[ct + 1:]

        if ct >= 1:
            st += 'G'
            flat = flat[1:3] + flat[:1] + flat[3:]

        st += 'L'
        flat = flat[1:] + flat[:1]
        
    if flat[0] == 1: return st, m

def main():
    def get_line():
        return [0 if x == 'E' else int(x) for x in input().split()]

    for cas in range(int(input())):
        k = int(input())
        grid = [get_line() for i in range(2)]
        assert all(len(row) == 2*k + 1 for row in grid)
        res = solve(grid)
        if res is None:
            print('SURGERY FAILED')
        else:
            print('SURGERY COMPLETE')
            st, m = res
            print(st)
            for shortcut in list(m.items()): print(*shortcut)
            print('DONE')

main()