Codeforces Round #237 (Div. 2)B. Marathon解题报告

来源：互联网发布：银行从业资格考试软件编辑：程序博客网时间：2024/05/16 15:03

地址：http://codeforces.com/contest/404/problem/B

题意:运动员在一个a*a的正方形跑道沿着逆时针跑，每隔d米就喝一瓶水，求每次喝水的坐标，题目不难，模拟题一道

开始挂在了第八组上了，代码如下

#include <iostream>#include <cstdio>#include <cmath>#include <algorithm>using namespace std;void prin(double s,double len){    int m=(int)floor(s/len);    int t=m;    double r=s-m*len;    t=t%4;    switch(t)    {        case 0:        {            printf("%.10lf 0.0000000000\n",r);break;        }        case 1:        {            printf("%.10lf %.10lf\n",len,r);break;        }        case 2:        {            printf("%.10lf %.10lf\n",len-r,len);break;        }        case 3:        {            printf("0.0000000000 %.10lf\n",len-r);break;        }    }}int main(){    double a,d;    int n,i;    scanf("%lf%lf",&a,&d);scanf("%d",&n);    for(i=1;i<=n;i++)        prin(i*d,a);return 0;}

错误数据：1 100000100000
原因：int造成的精度损失，改成long long 即可
正确代码：
#include <iostream>#include <cstdio>#include <cmath>#include <algorithm>using namespace std;void prin(double s,double len){    long long m=(long long)floor(s/len);    long long t=m;    double r=s-m*len;    t=t%4;    switch(t)    {        case 0:        {            printf("%.10lf 0.0000000000\n",r);break;        }        case 1:        {            printf("%.10lf %.10lf\n",len,r);break;        }        case 2:        {            printf("%.10lf %.10lf\n",len-r,len);break;        }        case 3:        {            printf("0.0000000000 %.10lf\n",len-r);break;        }    }}int main(){    double a,d;    long n,i;    scanf("%lf%lf",&a,&d);scanf("%d",&n);    for(i=1;i<=n;i++)        prin(i*d,a);return 0;}

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