Submission #1152405

#	Time	Username	Problem	Language	Result	Execution time	Memory
1152405		dzuizz	Geometrija (COCI21_geometrija)	C++20	50 / 110	1093 ms	25200 KiB

geometrija

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define Point pair<int,int>
#define x first
#define y second
struct Line {
	Point p,q;
	
	Line(int a=0, int b=0, int c=0, int d=0){
		p=Point(a,b);
		q=Point(c,d);
	}
};
int cross(Point A, Point B, Point C){
	int xAB=B.x-A.x, yAB=B.y-A.y;
	int xAC=C.x-A.x, yAC=C.y-A.y;
	int res=xAB*yAC-xAC*yAB;
	if(res<0) return -1;
	if(res==0) return 0;
	return 1;
}
int isIntersect(Line A, Line B) {
	return cross(A.p,A.q,B.p) != cross(A.p,A.q,B.q) && cross(B.p,B.q,A.p) != cross(B.p,B.q,A.q);
}
signed main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int n; cin>>n;
	Point a[n];
	for(int i=0;i<n;++i) cin>>a[i].x>>a[i].y;
	vector<pair<pair<int,int>,Line>> lines;
	for(int i=0;i<n;++i) for(int j=i+1;j<n;++j){
		lines.push_back({{i,j},Line(a[i].x,a[i].y,a[j].x,a[j].y)});
	}
	int ans=0;
	int sz=lines.size();
	for(int i=0;i<sz;++i) {
		bool f=0;
		for(int j=0;j<sz&&!f;++j) if(i!=j
				&&lines[i].first.first!=lines[j].first.first
				&&lines[i].first.second!=lines[j].first.first
				&&lines[i].first.first!=lines[j].first.second
				&&lines[i].first.second!=lines[j].first.second) {
			f|=isIntersect(lines[i].second,lines[j].second);
		}
		ans+=(!f);
	}
	cout<<ans<<'\n';
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 0 / 60