class Solution {
    public int[] prisonAfterNDays(int[] cells, int N) {
        int prev[] = Arrays.copyOf(cells, cells.length);
        int in = 0;
        int i,j;
        int mask = 1 << 7;
        int maskFirst = (1 << 7) - 1;
        int maskLast = maskFirst << 1;

        for (i = 0; i < 8; i++) {
            if(cells[i] == 1) {
                in = in | mask;
            }
            mask >>= 1;
        }

        N = (N - 1) % 14 + 1;
        int left, right , res;
        for( i = 0; i < N; i++) {
            left = in << 1;
            right = in >> 1;
            res = left ^ right;
            res =~res;

            res = res & maskFirst;
            res =res & maskLast;
            in = res;
        }

        for (i = 7; i >=0 ; i--) {
            if( (in & 1) == 1) {
                cells[i] = 1;
            } else {
                cells[i] = 0;
            }
            in >>= 1;
        }
        return cells;
    }
}