1118 Lining Up

 1 #include <iostream>
 2 using namespace std;
 3 #define MAXN 700
 4 struct Point{
 5     int x,y;
 6 }p[MAXN];
 7 int main(){
 8     int N;
 9     cin>>N;
10     while(N){
11         int i,j,k;
12         for(i=0;i<N;++i){
13             cin>>p[i].x>>p[i].y;
14         }
15         int max = 0;
16         for(i=0;i<N;++i){
17             for(j=i+1;j<N;++j){
18                 int s = 2;
19                 for(k=j+1;k<N;++k){
20                     int t1 = (p[i].x - p[j].x)*(p[j].y - p[k].y);
21                     int t2 = (p[i].y - p[j].y)*(p[j].x - p[k].x);
22                     if(t1 == t2)
23                         s++;
24                 }
25                 if(s>max)
26                     max = s;
27             }
28         }
29         cout<<max<<endl;
30         cin>>N;
31     }
32     return 0;
33 }