题目地址：http://acm.hdu.edu.cn/game/entry/problem/show.php?chapterid=2§ionid=2&problemid=1
试了用JAVA WR
思路来自：http://blog.csdn.net/niushuai666/article/details/7013352
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cmath>
#include <sstream>
#include <vector>
using namespace std;
#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define REPD(i,a,b) for(int i=a;i>=(int)b;i--)int f[21];
int main()
{f[0]=0; f[1]=1; REP(i,2,20+1) f[i]=f[i-1]+f[i-2];int n;while(scanf("%d",&n)==1){if(n<=20) {printf("%d\n", f[n]);continue;}double t=-0.5*log(5.0)/log(10.0) + (double(n)*log((sqrt(5.0)+1.0)/2.0)/log(10.0));t-=floor(t); //取小数t=pow(10,t);while(t<1000) t*=10;printf("%d\n", int(t));}return 0;
}