HDU 2013（递推&递归_D题）解题报告

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
#include<stack>
#include<bitset>
#include<cstdlib>
#include<cmath>
#include<set>
#include<list>
#include<deque>
#include<map>
#include<queue>
using namespace std;
typedef long long ll;
const double PI = acos(-1.0);
const double eps = 1e-6;


int main(void){
    int N =0;
    while(~scanf("%d",&N)){
        ll t =1;
        for(int i=0;i<N-1;i++){
            t=(t+1)*2;
        }
        printf("%lld\n",t);
    }

    return 0;

}