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: Note that because the prison is a row, the first and the last cells in the row can't have two adjacent neighbors. You are given an integer array cells where cells[i] == 1 if the ith cell is occupied and cells[i] == 0 if the ith cell is vacant, and you are given an integer n. Return the state of the prison after n days (i.e., n such changes described above).