#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cctype> #include<vector> #include<cmath> using namespace std; int main(void){ int a[55]; a[0] = 0; a[1] = 3; a[2] = 6; a[3] = 6; int n; for (int i = 4; i < 55; i++) { a[i] = a[i - 1] + a[i - 2] * 2; } while (cin >> n) { cout << a[n] << endl; } } |
Double click to view unformatted code.