贪心—— Zoj_3589

难点不在贪心，在于对字符串的处理，字符串处理为数字sscanf就可以了

#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<math.h>
using namespace std;

struct data
{
    double x,y;
    int time;
}s[100009];

double dis[100009];

double fdis(double x0,double y0,double x1,double y1)
{
    double all=(x0-x1)*(x0-x1)+(y0-y1)*(y0-y1);
    return sqrt(all);
}

int cmp(data a,data b)
{
    return a.time<b.time;
}

int main()
{
    char str[1009];
    scanf("%s",str);
    int k;
    int end=0;

    while(1)
    {
        int i;
        int add=0;
        scanf("%d",&k);
        while(1)
        {
            if(scanf("%s",str)==EOF)
            {
                end=1;
                break;
            }
            if(strcmp(str,"[HitObjects]")==0)
            {
                break;
            }
            
            sscanf(str,"%lf,%lf,%d,%*lf,%*lf",&s[add].x,&s[add].y,&s[add].time);
            add++;
        }

        if(k==1)
        {
            printf("0.000\n");
        }
        else
        {
            sort(&s[0],&s[add],cmp);
            for(i=0;i<add-1;i++)
            {
                dis[i]=fdis(s[i].x,s[i].y,s[i+1].x,s[i+1].y);
            }
            sort(&dis[0],&dis[add-1]);

            printf("%.3lf\n",dis[add-k]);
        }

        if(end==1)
        {
            break;
        }
    }

    return 0;
}