hdu-1041（大数模板）

#include<iostream>
#include<cstdio>
#include<string> 
using namespace std;
string str[1010];
string add(string s1,string s2)
{
    if(s1.length()<s2.length())
    {
        string tmp=s1;
        s1=s2;
        s2=tmp;
    }
    int l1=s1.length(),l2=s2.length(),i,j;
    for(i=l1-1,j=l2-1;i>=0;i--,j--)
    {
        s1[i]=char(s1[i]+(j>=0?s2[j]-‘0‘:0));
        if(s1[i]-‘0‘>=10)
        {
            s1[i]=char((s1[i]-‘0‘)%10+‘0‘);
            if(i) s1[i-1]++;
            else s1="1"+s1;
        }
    }
    return s1;
}
int main(void)
{
    str[1]="0",str[2]="1",str[3]="1",str[4]="3",str[5]="5",str[6]="11";
    for(int i=7;i<=1005;i++)
    {
        str[i]=add(add(str[i-2],str[i-2]),str[i-1]);
    } 
    int n;
    while(~scanf("%d",&n))
    {
        cout<<str[n]<<endl;
    }
    return 0;
}