Cod sursa(job #1338619)

Utilizator lauratalaatlaura talaat lauratalaat Data 10 februarie 2015 10:13:06
Problema Trapez Scor 10
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.91 kb
#include<stdio.h>
#include<algorithm>
using namespace std;
struct bine { int x ; int y ;};
bine v[1001],v2[500001];
int cmmdc ( int a , int b){
	int r;
	while(b!=0){
		r=a%b;
		a=b;
		b=r;
	}
	return a;
}
bool sortare ( bine a , bine b ){
	if(a.x!=b.x)
		return a.x<b.x;
	return a.y<b.y;
}
int main(){
	int n,i,j,x1,y1,l,lmax,p,k=0;
	freopen("trapez.in","r",stdin);
	freopen("trapez.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)
		scanf("%d %d",&v[i].x,&v[i].y);
	for(i=1;i<=n-1;i++)
		for(j=i+1;j<=n;j++){
			x1=v[i].x-v[j].x;
			y1=v[i].y-v[j].y;
			p=cmmdc(x1,y1);
			x1=x1/p;
			y1=y1/p;
			k++;
			v2[k].x=x1;
			v2[k].y=y1;
		}
	sort(v2+1,v2+k+1,sortare);
	l=1; lmax=1;
	for(i=1;i<=k-1;i++)
		if(v2[i].x==v2[i+1].x&&v2[i].y==v2[i+1].y)
			l++;
		else{
			if(l>lmax)
				lmax=l;
			l=1;
		}
	if(l>lmax)
		lmax=l;
	printf("%d\n",lmax*(lmax-1)/2);
	return 0;
}