dinamikus-betus

#include <iostream>

using namespace std;

int main()
{
    int n,a[40],b[40],c[40],d[40];
    cout<<"N ";cin>>n;
    a[1]=1;b[1]=1;c[1]=1;d[1]=1;
    for(int i=2;i<=n;i++)
    {
        a[i]=a[i-1]+c[i-1]+d[i-1];
        b[i]=b[i-1]+c[i-1]+d[i-1];
        c[i]=a[i-1]+b[i-1]+c[i-1]+d[i-1];
        d[i]=a[i-1]+b[i-1]+c[i-1]+d[i-1];

    }
    cout<<a[n]+b[n]+c[n]+d[n];
    return 0;
}