pre { white-space: pre !important; word-wrap: normal !important; overflow-x: auto !important; display: block !important; font-family: "Consolas", "Monaco", "Courier New", …
include <bits/stdc++.h>
using namespace std;
int dp[55];
int f(int x)
{
if(dp[x]!=-1) return dp[x];
return dp[x]=f(x-1)+f(x-2)*2;//别和数学的弄混了
}
int main()
{
int n;
while(cin>>n)
{
mem…