Submission #348138

#	Time	Username	Problem	Language	Result	Execution time	Memory
348138		algorithm16	Fence (CEOI08_fence)	C++14	100 / 100	4 ms	364 KiB

fence

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
vector <pair<int,int> > v1,v2,v3;
vector <int> ind,c1;
int x[105][105];
bool comp(int ind1,int ind2) {
	return v2[ind1]<v2[ind2];
}
int ccw(pair <int,int> a,pair <int,int> b,pair <int,int> c) {
	return a.first*(b.second-c.second)+b.first*(c.second-a.second)+c.first*(a.second-b.second);
}
vector <int> convex_hull(vector <int> v) {
	vector <int> g,d;
	g.push_back(v[0]);
	g.push_back(v[1]);
	for(int i=2;i<v.size();i++) {
		while(g.size()>=2 && ccw(v2[g[g.size()-2]],v2[g.back()],v2[v[i]])>0) {
			g.pop_back();
		}
		g.push_back(v[i]);
	}
	reverse(v.begin(),v.end());
	d.push_back(v[0]);
	d.push_back(v[1]);
	for(int i=2;i<v.size();i++) {
		while(d.size()>=2 && ccw(v2[d[d.size()-2]],v2[d.back()],v2[v[i]])>0) {
			d.pop_back();
		}
		d.push_back(v[i]);
	}
	g.pop_back();
	d.pop_back();
	for(int i=0;i<d.size();i++) {
		g.push_back(d[i]);
	}
	return g;
}
int check(int ind1) {
	for(int i=0;i<c1.size()-1;i++) {
		if(ccw(v2[c1[i]],v2[c1[i+1]],v1[ind1])>0) return 0;
	}
	if(ccw(v2[c1.back()],v2[c1[0]],v1[ind1])>0) return 0;
	return 1;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int n,m,sol=0;
	cin >> n >> m;
	for(int i=0;i<n;i++) {
		int x,y;
		cin >> x >> y;
		v2.push_back(make_pair(x,y));
		ind.push_back(i);
	}
	for(int i=0;i<m;i++) {
		int x,y;
		cin >> x >> y;
		v1.push_back(make_pair(x,y));
	}
	sort(ind.begin(),ind.end(),comp);
	c1=convex_hull(ind);
	for(int i=0;i<m;i++) {
		if(check(i)) v3.push_back(v1[i]);
	}
	sol+=111*(v1.size()-v3.size());
	if(v3.size()==0) {
		cout << sol;
		return 0;
	}
	for(int i=0;i<n;i++) {
		for(int j=0;j<n;j++) {
			x[i][j]=1e9;
			if(i==j) continue;
			int a1=0;
			for(int k=0;k<v3.size();k++) {
				if(ccw(v2[i],v2[j],v3[k])>0) a1+=1;
			}
			if(!a1) {
				x[i][j]=1;
			}
		}
	}
	for(int i=0;i<n;i++) {
		for(int j=0;j<n;j++) {
			for(int k=0;k<n;k++) {
				x[j][k]=min(x[j][k],x[j][i]+x[i][k]);
			}
		}
	}
	int mini=1e9;
	for(int i=0;i<n;i++) {
		mini=min(mini,x[i][i]);
	}
	cout << sol+20*mini;
	return 0;
}

Compilation message (stderr)

fence.cpp: In function 'std::vector<int> convex_hull(std::vector<int>)':
fence.cpp:18:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |  for(int i=2;i<v.size();i++) {
      |              ~^~~~~~~~~
fence.cpp:27:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |  for(int i=2;i<v.size();i++) {
      |              ~^~~~~~~~~
fence.cpp:35:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  for(int i=0;i<d.size();i++) {
      |              ~^~~~~~~~~
fence.cpp: In function 'int check(int)':
fence.cpp:41:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |  for(int i=0;i<c1.size()-1;i++) {
      |              ~^~~~~~~~~~~~
fence.cpp: In function 'int main()':
fence.cpp:80:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |    for(int k=0;k<v3.size();k++) {
      |                ~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10