1 #include<iostream> 2 #include<set> 3 #include<stdio.h> 4 #include<math.h> 5 #include<algorithm> 6 #define MAXN 705 7 using namespace std; 8 int num; 9 double p[MAXN][2]; 10 double a[MAXN*MAXN]; 11 set<int> coll; 12 set<int>::iterator pos; 13 multiset<int> coll_main; 14 int main() 15 { 16 //freopen("acm.acm","r",stdin); 17 int i; 18 int max; 19 int j; 20 int k; 21 int t; 22 double value; 23 int num; 24 double s2; 25 scanf("%d",&num); 26 max = 0; 27 for(i = 0; i < num; ++ i) 28 { 29 scanf("%lf%lf",&p[i][0],&p[i][1]); 30 } 31 for(i = 0; i < num; ++ i) 32 { 33 k = 0; 34 for(j = 0; j < num; ++ j) 35 { 36 if(i != j) 37 { 38 value = (p[i][0] - p[j][0]) / (p[i][1] - p[j][1]); 39 a[k] = value; 40 ++ k; 41 } 42 } 43 sort(a,a + k); 44 s2 = a[0]; 45 j = 0; 46 for(t = 0; t < k; ++ t) 47 { 48 if(a[t] == s2) 49 ++ j; 50 else 51 { 52 if(j > max) 53 { 54 max = j; 55 } 56 s2 = a[t]; 57 -- t; 58 j = 0; 59 } 60 } 61 if(j > max) 62 max = j; 63 } 64 ++max; 65 cout<<max<<endl; 66 }