human
I found an interesting problem on https://leetcode.com/problems/prison-cells-after-n-days/:
There are 8 prison cells in a row, and each cell is either occupied or vacant.
Each day, whether the cell is occupied or vacant changes according to the following rules:

If a cell has two adjacent neighbors that are both occupied or both vacant, then the cell becomes occupied.
Otherwise, it becomes vacant.

(Note that because the prison is a row, the first and the last cells in the row can't have two adjacent neighbors.)
We describe the current state of the prison in the following way: cells[i] == 1 if the i-th cell is occupied, else cells[i] == 0.
Given the initial state of the prison, return the state of the prison after N days (and N such changes described above.)
 



Example 1:
Input: cells = [0,1,0,1,1,0,0,1], N = 7
Output: [0,0,1,1,0,0,0,0]
Explanation: 
The following table summarizes the state of the prison on each day:
Day 0: [0, 1, 0, 1, 1, 0, 0, 1]
Day 1: [0, 1, 1, 0, 0, 0, 0, 0]
Day 2: [0, 0, 0, 0, 1, 1, 1, 0]
Day 3: [0, 1, 1, 0, 0, 1, 0, 0]
Day 4: [0, 0, 0, 0, 0, 1, 0, 0]
Day 5: [0, 1, 1, 1, 0, 1, 0, 0]
Day 6: [0, 0, 1, 0, 1, 1, 0, 0]
Day 7: [0, 0, 1, 1, 0, 0, 0, 0]


Example 2:
Input: cells = [1,0,0,1,0,0,1,0], N = 1000000000
Output: [0,0,1,1,1,1,1,0]

 
Note:

cells.length == 8
cells[i] is in {0, 1}
1 <= N <= 10^9

I tried it in Python, but could not do it. Can you solve it?
assistant
#Here is the Python code you requested.

# class Solution:
#     def prisonAfterNDays(self, cells: List[int], N: int) -> List[int]:
#         n = N
#         currCells = cells[:]
#         while n > 0:
#             for i in range(len(cells)):
#                 if i == 0 or i == len(cells)-1:
#                     currCells[i] = 0
#                 elif cells[i-1] == cells[i+1]:
#                     currCells[i] = 1
#                 else:
#                     currCells[i] = 0
#             cells = currCells[:]
#             n -= 1
#         return cells

class Solution:
    def prisonAfterNDays(self, cells, N):
        
        seen = {}
        while N:
            seen.setdefault(str(cells), N)
            print(seen)
            N -= 1
            cells = [0] + [cells[i - 1] ^ cells[i + 1] ^ 1 for i in range(1, 7)] + [0]
            if str(cells) in seen:
                N %= seen[str(cells)] - N
        return cells