oj.uz

Submission #56603

# Submission time Handle Problem Language Result Execution time Memory
56603 2018-07-12T02:53:36 Z ksun48 Fences (JOI18_fences) C++14
51 / 100
 1000 ms 202176 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef double T;

const double PI = 3.1415926535;
const double EPS = 0.0000001;
struct P {
	T x, y;
	P() : x(0), y(0){}
	P(T x, T y) : x(x), y(y) {}
	P operator +(P p){
		return P(x+p.x,y+p.y);
	}
	P operator -(P p){
		return P(x-p.x,y-p.y);
	}
	P operator *(T t){
		return P(x*t, y*t);
	}
	P operator /(T t){
		return P(x,y) * (1.0/t);
	}
	T dist(){
		return sqrt(x*x+y*y);
	}
	T angle(){
		return atan2(y,x);
	}
	P rotate(T angle){
		double c = cos(angle);
		double s = sin(angle);
		return P(c*x-s*y,s*x+c*y);
	}
};
double get(){
	double r;
	cin >> r;
	r += (double)((rand() % 2000) - 1000) / 20000000.0;
	return r;
}
double ang;
int wind(P a1, P b1){
	// 0, 1, -1 if it crosses y = tan(ang) * x
	P a = a1.rotate(-ang);
	P b = b1.rotate(-ang);
	if((a-b).dist() < EPS) return 0;
	if(a.y > 0 && b.y > 0) return 0;
	if(a.y < 0 && b.y < 0) return 0;
	double nx = a.x + (0.0 - a.y) / (b.y - a.y) * (b.x - a.x);
	if(nx < 0) return 0;
	if(a.y < b.y) return 1;
	return -1;
}
double S;
int bad(P a, P b){
	// check if this intersects
	// [-S, S] cross S
	a.y -= S;
	b.y -= S;
	if((a-b).dist() < EPS) return 0;
	if(a.y > 0 && b.y > 0) return 0;
	if(a.y < 0 && b.y < 0) return 0;
	double nx = a.x + (0.0 - a.y) / (b.y - a.y) * (b.x - a.x);
	return (nx >= -S) && (nx <= S);
}
int ok(P a, P b){
	if(bad(a.rotate(0),b.rotate(0))) return 0;
	if(bad(a.rotate(PI/2.0), b.rotate(PI/2.0))) return 0;
	if(bad(a.rotate(2.0*PI/2.0), b.rotate(2.0*PI/2.0))) return 0;
	if(bad(a.rotate(3.0*PI/2.0), b.rotate(3.0*PI/2.0))) return 0;
	return 1;
}
double dot(P a, P b){
	return a.x*b.x + a.y*b.y;
}
int main(){
	ang = 0.001;
	int n;
	cin >> n >> S;
	vector<pair<P,P> > segs;
	vector<pair<int,int> > idx;
	for(int i = 0; i < n; i++){
		P a, b;
		a.x = get(); a.y = get(); b.x = get(); b.y = get();
		segs.push_back({a,b});
	}
	segs.push_back({P(S,S),P(S,S)});
	segs.push_back({P(S,-S),P(S,-S)});
	segs.push_back({P(-S,S),P(-S,S)});
	segs.push_back({P(-S,-S),P(-S,-S)});
	S -= 0.0001;
	// get from each point to each other point with nonzero winding number.
	// winding number adds one when 
	P origin = P(0,0);
	vector<P> pts;
	for(int i = 0; i < segs.size(); i++){
		idx.push_back({pts.size(), pts.size()+1});
		pts.push_back(segs[i].first);
		pts.push_back(segs[i].second);
	}
	vector<pair<int,int> > edges;
	vector<int> winds;
	vector<double> length;
	for(int i = 0; i < pts.size(); i++){
		for(int j = 0; j < pts.size(); j++){
			if( !ok(pts[i], pts[j]) ) continue;
			edges.push_back({i,j});
			winds.push_back( wind(pts[i],pts[j]) );
			length.push_back((pts[i]-pts[j]).dist());
		}
	}
	for(int i = 0; i < pts.size(); i++){
		for(int j = 0; j < segs.size(); j++){
			P p1 = segs[j].first - pts[i];
			P p2 = segs[j].second - pts[i];
			if((p1-p2).dist() < EPS) continue;
			double len = dot(p2-p1, origin-p1) / (p2-p1).dist();
			P r = p1 + (p2 - p1) * (len) / (p2-p1).dist();
			if((p1-r).dist() + (p2-r).dist() > (p1-p2).dist() + EPS){
				continue;
			}
			if( !ok(pts[i], pts[i] + r) ) continue;
			double cost = r.dist();
			edges.push_back({i,idx[j].first});
			winds.push_back( wind(pts[i], pts[i] + r) + wind(pts[i] + r, pts[idx[j].first]) );
			length.push_back(cost);

			edges.push_back({idx[j].first, i});
			winds.push_back( -winds[winds.size()-1] );
			length.push_back(cost);
		}
	}
	for(int i = 0; i < segs.size(); i++){
		assert(ok(segs[i].first, segs[i].second));
		edges.push_back({idx[i].first, idx[i].second});
		winds.push_back(wind(segs[i].first, segs[i].second));
		length.push_back(0.0);
		edges.push_back({idx[i].second, idx[i].first});
		winds.push_back(wind(segs[i].second, segs[i].first));
		length.push_back(0.0);
	}
	/*for(int i = 0; i < pts.size(); i++){
		cout << i << " " << pts[i].x << " " << pts[i].y << '\n';
	}
	cout << '\n';
	for(int i = 0; i < edges.size(); i++){
		cout << edges[i].first << " " << edges[i].second << " " << winds[i] << " " << length[i] << '\n';
	}*/
	int maxw = n + 4;
	int N = pts.size() * maxw;
	double dist[N][N];
	for(int i = 0; i < N; i++){
		for(int j = 0; j < N; j++){
			dist[i][j] = 20000.0;
		}
		dist[i][i] = 0;
	}
	for(int i = 0; i < edges.size(); i++){
		for(int r = 0; r < maxw; r++){
			int w = winds[i];
			if(w + r < 0 || w + r >= maxw) continue;
			double &v = dist[edges[i].first * maxw + r][edges[i].second * maxw + w + r];
			v = min(v, length[i]);
		}
	}
	for(int k = 0; k < N; k++){
		for(int i = 0; i < N; i++){
			for(int j = 0; j < N; j++){
				dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
			}
		}
	}
	double ans = 20000.0;
	for(int i = 0; i < pts.size(); i++){
		ans = min(ans, dist[i * maxw + 0][i * maxw + 1]);
	}
	printf("%.10lf\n", ans);
}

Compilation message

fences.cpp: In function 'int main()':
fences.cpp:97:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < segs.size(); i++){
                 ~~^~~~~~~~~~~~~
fences.cpp:105:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~
fences.cpp:106:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < pts.size(); j++){
                  ~~^~~~~~~~~~~~
fences.cpp:113:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~
fences.cpp:114:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < segs.size(); j++){
                  ~~^~~~~~~~~~~~~
fences.cpp:134:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < segs.size(); i++){
                 ~~^~~~~~~~~~~~~
fences.cpp:159:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < edges.size(); i++){
                 ~~^~~~~~~~~~~~~~
fences.cpp:175:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 376 KB Output is correct
2 Correct 3 ms 452 KB Output is correct
3 Correct 4 ms 452 KB Output is correct
4 Correct 3 ms 576 KB Output is correct
5 Correct 3 ms 576 KB Output is correct
6 Correct 4 ms 676 KB Output is correct
7 Correct 3 ms 676 KB Output is correct
8 Correct 4 ms 676 KB Output is correct
9 Correct 3 ms 676 KB Output is correct
10 Correct 4 ms 676 KB Output is correct
11 Correct 3 ms 752 KB Output is correct
12 Correct 4 ms 752 KB Output is correct
13 Correct 2 ms 752 KB Output is correct
14 Correct 1 ms 752 KB Output is correct
15 Correct 3 ms 752 KB Output is correct
16 Correct 4 ms 752 KB Output is correct
17 Correct 4 ms 760 KB Output is correct
18 Correct 4 ms 764 KB Output is correct
19 Correct 3 ms 768 KB Output is correct
20 Correct 2 ms 772 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 376 KB Output is correct
2 Correct 3 ms 452 KB Output is correct
3 Correct 4 ms 452 KB Output is correct
4 Correct 3 ms 576 KB Output is correct
5 Correct 3 ms 576 KB Output is correct
6 Correct 4 ms 676 KB Output is correct
7 Correct 3 ms 676 KB Output is correct
8 Correct 4 ms 676 KB Output is correct
9 Correct 3 ms 676 KB Output is correct
10 Correct 4 ms 676 KB Output is correct
11 Correct 3 ms 752 KB Output is correct
12 Correct 4 ms 752 KB Output is correct
13 Correct 2 ms 752 KB Output is correct
14 Correct 1 ms 752 KB Output is correct
15 Correct 3 ms 752 KB Output is correct
16 Correct 4 ms 752 KB Output is correct
17 Correct 4 ms 760 KB Output is correct
18 Correct 4 ms 764 KB Output is correct
19 Correct 3 ms 768 KB Output is correct
20 Correct 2 ms 772 KB Output is correct
21 Correct 4 ms 780 KB Output is correct
22 Correct 14 ms 1036 KB Output is correct
23 Correct 20 ms 1040 KB Output is correct
24 Correct 16 ms 1044 KB Output is correct
25 Correct 20 ms 1176 KB Output is correct
26 Correct 13 ms 1176 KB Output is correct
27 Correct 14 ms 1176 KB Output is correct
28 Correct 17 ms 1176 KB Output is correct
29 Correct 18 ms 1176 KB Output is correct
30 Correct 15 ms 1176 KB Output is correct
31 Correct 21 ms 1176 KB Output is correct
32 Correct 18 ms 1176 KB Output is correct
33 Correct 22 ms 1176 KB Output is correct
34 Correct 18 ms 1176 KB Output is correct
35 Correct 15 ms 1176 KB Output is correct
36 Correct 12 ms 1176 KB Output is correct
37 Correct 10 ms 1176 KB Output is correct
38 Correct 4 ms 1176 KB Output is correct
39 Correct 9 ms 1176 KB Output is correct
40 Correct 4 ms 1176 KB Output is correct
41 Correct 3 ms 1176 KB Output is correct
42 Correct 5 ms 1176 KB Output is correct
43 Correct 7 ms 1176 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 376 KB Output is correct
2 Correct 3 ms 452 KB Output is correct
3 Correct 4 ms 452 KB Output is correct
4 Correct 3 ms 576 KB Output is correct
5 Correct 3 ms 576 KB Output is correct
6 Correct 4 ms 676 KB Output is correct
7 Correct 3 ms 676 KB Output is correct
8 Correct 4 ms 676 KB Output is correct
9 Correct 3 ms 676 KB Output is correct
10 Correct 4 ms 676 KB Output is correct
11 Correct 3 ms 752 KB Output is correct
12 Correct 4 ms 752 KB Output is correct
13 Correct 2 ms 752 KB Output is correct
14 Correct 1 ms 752 KB Output is correct
15 Correct 3 ms 752 KB Output is correct
16 Correct 4 ms 752 KB Output is correct
17 Correct 4 ms 760 KB Output is correct
18 Correct 4 ms 764 KB Output is correct
19 Correct 3 ms 768 KB Output is correct
20 Correct 2 ms 772 KB Output is correct
21 Correct 4 ms 780 KB Output is correct
22 Correct 14 ms 1036 KB Output is correct
23 Correct 20 ms 1040 KB Output is correct
24 Correct 16 ms 1044 KB Output is correct
25 Correct 20 ms 1176 KB Output is correct
26 Correct 13 ms 1176 KB Output is correct
27 Correct 14 ms 1176 KB Output is correct
28 Correct 17 ms 1176 KB Output is correct
29 Correct 18 ms 1176 KB Output is correct
30 Correct 15 ms 1176 KB Output is correct
31 Correct 21 ms 1176 KB Output is correct
32 Correct 18 ms 1176 KB Output is correct
33 Correct 22 ms 1176 KB Output is correct
34 Correct 18 ms 1176 KB Output is correct
35 Correct 15 ms 1176 KB Output is correct
36 Correct 12 ms 1176 KB Output is correct
37 Correct 10 ms 1176 KB Output is correct
38 Correct 4 ms 1176 KB Output is correct
39 Correct 9 ms 1176 KB Output is correct
40 Correct 4 ms 1176 KB Output is correct
41 Correct 3 ms 1176 KB Output is correct
42 Correct 5 ms 1176 KB Output is correct
43 Correct 7 ms 1176 KB Output is correct
44 Execution timed out 1060 ms 202176 KB Time limit exceeded
45 Halted 0 ms 0 KB -