Submission #892118

#	Time	Username	Problem	Language	Result	Execution time	Memory
892118		OAleksa	Fence (CEOI08_fence)	C++14	100 / 100	1 ms	348 KiB

fence

#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define int long long
const int N = 110;
struct point {
	int x, y;
};
vector<int> g[N];
vector<point> a(N), b(N);
int n, m, d[N], vis[N];
int cross(point a, point b, point c) {
	point v1 = {b.x - a.x, b.y - a.y};
	point v2 = {c.x - a.x, c.y - a.y};
	return v2.x * v1.y - v2.y * v1.x;
}
vector<point> convex_hull(vector<point> c) {
	sort(c.begin(), c.end(), [&](point a, point b) {
		return make_pair(a.x, a.y) < make_pair(b.x, b.y);
	});
	vector<point> up, down;
	for (int i = 0;i < n;i++) {
		while (up.size() >= 2 && cross(up[up.size() - 2], c[i], up.back()) > 0)
			up.pop_back();
		up.push_back(c[i]);
	}
	for (int i = n - 1;i >= 0;i--) {
		while (down.size() >= 2 && cross(down[down.size() - 2], c[i], down.back()) > 0)
			down.pop_back();
		down.push_back(c[i]);
	}
	vector<point> r = up;
	for (int i = 1;i < (int)down.size() - 1;i++)
		r.push_back(down[i]);
	return r;
}
signed main() {
	ios_base::sync_with_stdio(false);
  cout.tie(nullptr); 
  cin.tie(nullptr);
  //freopen("newbarn.in", "r", stdin);
  //freopen(newbarn.out", "w", stdout);
  int tt = 1;
  //cin >> tt;
  while (tt--) {
  	cin >> n >> m;
  	a.resize(n);
  	b.resize(m);
  	for (int i = 0;i < n;i++)
  		cin >> a[i].x >> a[i].y;
  	for (int i = 0;i < m;i++) 
  		cin >> b[i].x >> b[i].y;
  	//n->crveni
  	//m->zeleni
  	vector<point> ch = convex_hull(a);
  	vector<point> temp;
  	for (int i = 0;i < m;i++) {
  		int x = 1;
  		for (int j = 0;j < ch.size();j++) {
  			x &= (cross(ch[j], ch[(j + 1) % ch.size()], b[i]) > 0);
  		}
  		if (x > 0) 
  			temp.push_back(b[i]);
  	}
  	int ans = 111 * (m - (int)temp.size());
  	b = temp;
  	for (int i = 0;i < n;i++) {
  		for (int j = i + 1;j < n;j++) {
  			int x = 1, y = 1;
  			for (auto p : b) {
  				x &= (cross(a[i], a[j], p) > 0);
  				y &= (cross(a[i], a[j], p) < 0);
  			}
  			if (x > 0) 
  				g[i].push_back(j);
  			else if (y > 0)
  				g[j].push_back(i);
  		}
  	}
  	int mn = 1e18;
  	for (int i = 0;i < n;i++) {
  		queue<int> q;
  		q.push(i);
  		for (int j = 0;j < n;j++)
  			d[j] = 1e9, vis[j] = 0;
  		d[i] = 0;
  		vis[i] = 1;
  		while (!q.empty()) {
  			auto v = q.front();
  			q.pop();
  			for (auto u : g[v]) {
  				if (u == i) 
  					mn = min(mn, d[v] + 1);
  				if (vis[u])
  					continue;
  				d[u] = min(d[u], d[v] + 1);
  				q.push(u);
  				vis[u] = 1;
  			}
  		}
  	}
  	if (mn == 1e18)
  		mn = 0;
  	cout << ans + 20 * mn;
  }
  return 0;
}

Compilation message (stderr)

fence.cpp: In function 'int main()':
fence.cpp:60:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for (int j = 0;j < ch.size();j++) {
      |                    ~~^~~~~~~~~~~

• 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