poj 1118 Lining Up

#include<iostream>using namespace std;#define MAX 705struct Point{    int x,y;}p[MAX];int main(){    int n,i,j,k,a,b;    while(cin>>n&&n)    {        for(i=0;i<n;i++) cin>>p[i].x>>p[i].y;        int sum,max=0;        for(i=0;i<n;i++) for(j=i+1;j<n;j++) {     sum=2;     for(k=j+1;k<n;k++)     {         a=(p[i].y-p[k].y)*(p[j].x-p[k].x);         b=(p[i].x-p[k].x)*(p[j].y-p[k].y);         if(a==b) sum++;     }     if(max<sum) max=sum; } cout<<max<<endl;    }    return 0;}