Count ways to build street under given constraints

#include <bits/stdc++.h>
using namespace std;
// a street of n rows
long countWays(int n)
{
    long dp[2][n + 1];

    // base case
    dp[0][1] = 1;
    dp[1][1] = 2;

    for (int i = 2; i <= n; i++)
    {

        // ways of building houses in both
        // the spots of ith row
        dp[0][i] = dp[0][i - 1] + dp[1][i - 1];

        // ways of building an office in one of
        // the two spots of ith row
        dp[1][i] = dp[0][i - 1] * 2 + dp[1][i - 1];
    }

    // total ways for n rows
    return dp[0][n] + dp[1][n];
}

// driver program for checking above function
int main()
{

    int n = 5;
    cout << "Total no of ways with n = " << n
         << " are: " << countWays(n) << endl;
}