hdu 2604 汉诺塔III 递推

#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <string>#include <math.h>#include <stdlib.h>#include <time.h>using namespace std;typedef long long ll;int main(){    ll a[40];    int i,n;    a[1]=2;    for(i=2;i<=35;i++)        a[i]=a[i-1]*3+2;    while(~scanf("%d",&n))    {        printf("%lld\n",a[n]);    }    return 0;}