oj.uz

Submission #56646

# Submission time Handle Problem Language Result Execution time Memory
56646 2018-07-12T05:14:22 Z ksun48 Fences (JOI18_fences) C++14
51 / 100
 1000 ms 78044 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 = 15;
	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 7 ms 504 KB Output is correct
2 Correct 7 ms 612 KB Output is correct
3 Correct 6 ms 612 KB Output is correct
4 Correct 9 ms 612 KB Output is correct
5 Correct 5 ms 664 KB Output is correct
6 Correct 8 ms 792 KB Output is correct
7 Correct 5 ms 908 KB Output is correct
8 Correct 6 ms 908 KB Output is correct
9 Correct 6 ms 908 KB Output is correct
10 Correct 10 ms 908 KB Output is correct
11 Correct 7 ms 908 KB Output is correct
12 Correct 8 ms 908 KB Output is correct
13 Correct 9 ms 908 KB Output is correct
14 Correct 5 ms 908 KB Output is correct
15 Correct 10 ms 908 KB Output is correct
16 Correct 9 ms 908 KB Output is correct
17 Correct 8 ms 908 KB Output is correct
18 Correct 8 ms 908 KB Output is correct
19 Correct 8 ms 908 KB Output is correct
20 Correct 8 ms 908 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 504 KB Output is correct
2 Correct 7 ms 612 KB Output is correct
3 Correct 6 ms 612 KB Output is correct
4 Correct 9 ms 612 KB Output is correct
5 Correct 5 ms 664 KB Output is correct
6 Correct 8 ms 792 KB Output is correct
7 Correct 5 ms 908 KB Output is correct
8 Correct 6 ms 908 KB Output is correct
9 Correct 6 ms 908 KB Output is correct
10 Correct 10 ms 908 KB Output is correct
11 Correct 7 ms 908 KB Output is correct
12 Correct 8 ms 908 KB Output is correct
13 Correct 9 ms 908 KB Output is correct
14 Correct 5 ms 908 KB Output is correct
15 Correct 10 ms 908 KB Output is correct
16 Correct 9 ms 908 KB Output is correct
17 Correct 8 ms 908 KB Output is correct
18 Correct 8 ms 908 KB Output is correct
19 Correct 8 ms 908 KB Output is correct
20 Correct 8 ms 908 KB Output is correct
21 Correct 15 ms 908 KB Output is correct
22 Correct 34 ms 1388 KB Output is correct
23 Correct 43 ms 1388 KB Output is correct
24 Correct 42 ms 1388 KB Output is correct
25 Correct 30 ms 1388 KB Output is correct
26 Correct 62 ms 1388 KB Output is correct
27 Correct 32 ms 1388 KB Output is correct
28 Correct 30 ms 1388 KB Output is correct
29 Correct 35 ms 1388 KB Output is correct
30 Correct 34 ms 1388 KB Output is correct
31 Correct 48 ms 1388 KB Output is correct
32 Correct 56 ms 1388 KB Output is correct
33 Correct 35 ms 1388 KB Output is correct
34 Correct 36 ms 1388 KB Output is correct
35 Correct 45 ms 1388 KB Output is correct
36 Correct 34 ms 1388 KB Output is correct
37 Correct 25 ms 1388 KB Output is correct
38 Correct 9 ms 1388 KB Output is correct
39 Correct 36 ms 1388 KB Output is correct
40 Correct 13 ms 1388 KB Output is correct
41 Correct 10 ms 1388 KB Output is correct
42 Correct 13 ms 1388 KB Output is correct
43 Correct 26 ms 1388 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 504 KB Output is correct
2 Correct 7 ms 612 KB Output is correct
3 Correct 6 ms 612 KB Output is correct
4 Correct 9 ms 612 KB Output is correct
5 Correct 5 ms 664 KB Output is correct
6 Correct 8 ms 792 KB Output is correct
7 Correct 5 ms 908 KB Output is correct
8 Correct 6 ms 908 KB Output is correct
9 Correct 6 ms 908 KB Output is correct
10 Correct 10 ms 908 KB Output is correct
11 Correct 7 ms 908 KB Output is correct
12 Correct 8 ms 908 KB Output is correct
13 Correct 9 ms 908 KB Output is correct
14 Correct 5 ms 908 KB Output is correct
15 Correct 10 ms 908 KB Output is correct
16 Correct 9 ms 908 KB Output is correct
17 Correct 8 ms 908 KB Output is correct
18 Correct 8 ms 908 KB Output is correct
19 Correct 8 ms 908 KB Output is correct
20 Correct 8 ms 908 KB Output is correct
21 Correct 15 ms 908 KB Output is correct
22 Correct 34 ms 1388 KB Output is correct
23 Correct 43 ms 1388 KB Output is correct
24 Correct 42 ms 1388 KB Output is correct
25 Correct 30 ms 1388 KB Output is correct
26 Correct 62 ms 1388 KB Output is correct
27 Correct 32 ms 1388 KB Output is correct
28 Correct 30 ms 1388 KB Output is correct
29 Correct 35 ms 1388 KB Output is correct
30 Correct 34 ms 1388 KB Output is correct
31 Correct 48 ms 1388 KB Output is correct
32 Correct 56 ms 1388 KB Output is correct
33 Correct 35 ms 1388 KB Output is correct
34 Correct 36 ms 1388 KB Output is correct
35 Correct 45 ms 1388 KB Output is correct
36 Correct 34 ms 1388 KB Output is correct
37 Correct 25 ms 1388 KB Output is correct
38 Correct 9 ms 1388 KB Output is correct
39 Correct 36 ms 1388 KB Output is correct
40 Correct 13 ms 1388 KB Output is correct
41 Correct 10 ms 1388 KB Output is correct
42 Correct 13 ms 1388 KB Output is correct
43 Correct 26 ms 1388 KB Output is correct
44 Execution timed out 1071 ms 78044 KB Time limit exceeded
45 Halted 0 ms 0 KB -