bzoj1610

直接暴力。。

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;#define N 204#define Max 1000000000#define Sma 0.0000001struct _point{int x,y;}p[N];double line[N*N];int n;double draw(_point x, _point y){     int a=x.x, b=x.y, c=y.x, d=y.y;     if(a==c) return Max;     return double(b-d)/(a-c);     }double abss(double x){return (x<0)? -x:x;}bool equal(double a, double b){     return abss(a-b)<Sma;     }int main(){     scanf("%d",&n);    int ls=0;    for(int i=1;i<=n;i++) scanf("%d%d",&p[i].x, &p[i].y);    for(int i=1;i<=n;i++){            for(int j=i+1;j<=n;j++){                    line[++ls]= draw(p[i], p[j]);                    }            }    sort(line+1, line+ls+1);    int ans=1;    for(int i=2;i<=ls;i++) if(!equal(line[i], line[i-1])) ++ans;    printf("%d\n",ans);      return 0;}