5383. 給 N x 3 網格圖塗色的方案數
分類：ABA, ABC各6種，每個ABA可與2ABC+3ABA結合， 每個ABC可與2ABC+2ABA結合
class Solution:
def numOfWays(self, n: int) -> int:
same, diff = 6, 6 # 代表初始時第一行兩類各6種
for k in range(1, n):
same, diff = same * 3 + diff * 2, same * 2 + diff * 2
return (same + diff) % (10 ** 9 + 7)