hdu1568

来源：互联网发布：js实现5秒倒计时编辑：程序博客网时间：2024/06/05 03:22

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题意：输出斐波那契的前四位数

代码：

#include <queue>#include <cstdio>#include <cstring>#include <algorithm>#include <stdlib.h>#include <iostream>#include <math.h>using namespace std;int a[30];int main(){int i,j,n;double temp=(sqrt(5)+1)/2,t;a[0]=0;a[1]=1;for(i=2;i<=20;i++)    a[i]=a[i-1]+a[i-2];    while(scanf("%d",&n)!=EOF){        if(n<=20){            cout<<a[n]<<endl;            continue;        }                               //前四位推导公式：        t=n*log10(temp)-0.5*log10(5.0); //s=d.xxx*10^(len-4)        t-=floor(t);                    //log10(s)=log10(d.xxxxx)+log10(10^(len-4))=log10(d.xxxx)+len-4        t+=3;                           //log10(s)+4-len=log10(d.xxxx)        t=pow(10,t);                    //d.xxxx=10^(log10(s)+4-len)        while(t<1000)                   //s=(1/sqrt(5))*[(1+sqrt(5))/2.0]^i        t*=10;                          //len=(int)log10(s)+1        printf("%d\n",(int)t);          //d.xxxx=10^(log10(s)+4-((int)log10(s)+1))=10^(log10(s)-(int)log10(s)+3)    }    return 0;}

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