HDU 4709 Herding

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题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4709

思路：求最小的三角形面积，easy~~~~

#include <iostream>#include <stdio.h>#include <stdlib.h>#include <math.h>#include <string.h>#include <algorithm>using namespace std;#define maxn 110#define inf 0x3f3f3f3ftypedef struct point{    double x,y;}P;P node[maxn];double Distance(point a,point b){    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}int main(){    int T,n;    while(~scanf("%d",&T)){        while(T--){            scanf("%d",&n);            for(int i=0;i<n;i++){                scanf("%lf %lf",&node[i].x,&node[i].y);            }            if(n<3){                printf("Impossible\n");                continue;            }            double ans = inf ;            double a,b,c,p,temp;            for(int i=0;i<n;i++){                for(int j =i+1;j<n;j++){                    for(int k=j+1;k<n;k++){                            a=Distance(node[i],node[j]);                            b=Distance(node[i],node[k]);                            c=Distance(node[j],node[k]);                            p =(a+b+c)/2;                            temp=p*(p-a)*(p-b)*(p-c);                            temp=sqrt(temp);                            if(temp>=0.05 && temp<ans) ans = temp;                    }                }            }            if(ans == inf) printf("Impossible\n");            else            printf("%.2lf\n",ans);        }    }    return 0;}