2320. Count Number of Ways to Place Houses

class Solution:
    def countHousePlacements(self, n: int) -> int:
        mod = 10**9 + 7
        f = [1] * n
        g = [1] * n
        for i in range(1, n):
            f[i] = g[i - 1]
            g[i] = (f[i - 1] + g[i - 1]) % mod
        v = f[-1] + g[-1]
        return v * v % mod