D - Half of and a Half 大数

D - Half of and a Half

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u

Submit Status Practice HDU 1592

Description

Gardon bought many many chocolates from the A Chocolate Market (ACM). When he was on the way to meet Angel, he met Speakless by accident.
"Ah, so many delicious chocolates! I'll get half of them and a half!" Speakless said.
Gardon went on his way, but soon he met YZG1984 by accident....
"Ah, so many delicious chocolates! I'll get half of them and a half!" YZG1984 said.
Gardon went on his way, but soon he met Doramon by accident....
"Ah, so many delicious chocolates! I'll get half of them and a half!" Doramon said.
Gardon went on his way, but soon he met JGShining by accident....
"Ah, so many delicious chocolates! I'll get half of them and a half!" JGShining said.
.
.
.
After had had met N people , Gardon finally met Angel. He gave her half of the rest and a half, then Gardon have none for himself. Could you tell how many chocolates did he bought from ACM?

 

Input

Input contains many test cases.
Each case have a integer N, represents the number of people Gardon met except Angel. N will never exceed 1000;

 

Output

For every N inputed, tell how many chocolates Gardon had at first.

 

Sample Input

2

 

Sample Output

7

#include<cstdio>
#include<string.h>
using namespace std;
int ans[1000][510];
int main()
{
    //memset(ans,0,sizeof(ans));
    int n,i,j;
    while(scanf("%d",&n)!=EOF)
    {

        //i=300;
memset(ans,0,sizeof(ans));
ans[500]=1;
        while(n--)
        {
            int c=0;
            int s=0;

            for(i=500;i>=0;i--)
            {
                if(i==500)
                 s=ans[i]*2+1+c;
                 else s=ans[i]*2+c;
                ans[i]=s%10;
                c=s/10;

            }
        }
        for(i=0;i<=500;i++) if(ans[i]!=0) break;
        j=i;
        for(j=i;j<=500;j++) printf("%d",ans[j]);
        printf("\n");
    }
    return 0;
}