oj.uz

Submission #56650

# Submission time Handle Problem Language Result Execution time Memory
56650 2018-07-12T05:24:58 Z ksun48 Fences (JOI18_fences) C++14
51 / 100
 512 ms 4128 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 = 2;
	int N = pts.size() * maxw;

	vector<pair<int,double> > realedges[N];
	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;
			realedges[edges[i].first * maxw + r].push_back({edges[i].second * maxw + w + r, length[i]});
			//double &v = dist[edges[i].first * maxw + r][edges[i].second * maxw + w + r];
			//v = min(v, length[i]);
		}
	}
	// 100 * 1500
	double ans = 20000.0;
	for(int q = 0; q < pts.size(); q++){
		double dist[N];
		int vis[N];
		set<pair<double, int> > z;
		for(int i = 0; i < N; i++){
			if(i != q * maxw){
				dist[i] = 200000000000.0;
			} else {
				dist[i] = 0;
			}
			vis[i] = 0;
			z.insert({dist[i], i});
		}
		while(!z.empty()){
			auto x = *z.begin();
			z.erase(z.begin());
			vis[x.second] = 1;
			for(int r = 0; r < realedges[x.second].size(); r++){
				double newdist = x.first + realedges[x.second][r].second;
				int loc = realedges[x.second][r].first;
				if(vis[loc]) continue;
				if(newdist < dist[loc]){
					z.erase({dist[loc],loc});
					dist[loc] = newdist;
					z.insert({dist[loc],loc});
				}
			}
		}
		ans = min(ans, dist[q * 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:154:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < edges.size(); i++){
                 ~~^~~~~~~~~~~~~~
fences.cpp:165:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int q = 0; q < pts.size(); q++){
                 ~~^~~~~~~~~~~~
fences.cpp:182:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int r = 0; r < realedges[x.second].size(); r++){
                   ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 416 KB Output is correct
4 Correct 3 ms 620 KB Output is correct
5 Correct 2 ms 620 KB Output is correct
6 Correct 2 ms 620 KB Output is correct
7 Correct 2 ms 620 KB Output is correct
8 Correct 2 ms 620 KB Output is correct
9 Correct 3 ms 620 KB Output is correct
10 Correct 3 ms 620 KB Output is correct
11 Correct 2 ms 620 KB Output is correct
12 Correct 2 ms 620 KB Output is correct
13 Correct 2 ms 620 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 2 ms 628 KB Output is correct
17 Correct 2 ms 628 KB Output is correct
18 Correct 3 ms 628 KB Output is correct
19 Correct 4 ms 628 KB Output is correct
20 Correct 3 ms 636 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 416 KB Output is correct
4 Correct 3 ms 620 KB Output is correct
5 Correct 2 ms 620 KB Output is correct
6 Correct 2 ms 620 KB Output is correct
7 Correct 2 ms 620 KB Output is correct
8 Correct 2 ms 620 KB Output is correct
9 Correct 3 ms 620 KB Output is correct
10 Correct 3 ms 620 KB Output is correct
11 Correct 2 ms 620 KB Output is correct
12 Correct 2 ms 620 KB Output is correct
13 Correct 2 ms 620 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 2 ms 628 KB Output is correct
17 Correct 2 ms 628 KB Output is correct
18 Correct 3 ms 628 KB Output is correct
19 Correct 4 ms 628 KB Output is correct
20 Correct 3 ms 636 KB Output is correct
21 Correct 2 ms 636 KB Output is correct
22 Correct 3 ms 636 KB Output is correct
23 Correct 3 ms 636 KB Output is correct
24 Correct 3 ms 636 KB Output is correct
25 Correct 3 ms 636 KB Output is correct
26 Correct 4 ms 644 KB Output is correct
27 Correct 3 ms 644 KB Output is correct
28 Correct 4 ms 644 KB Output is correct
29 Correct 3 ms 644 KB Output is correct
30 Correct 3 ms 644 KB Output is correct
31 Correct 4 ms 644 KB Output is correct
32 Correct 3 ms 644 KB Output is correct
33 Correct 2 ms 644 KB Output is correct
34 Correct 2 ms 644 KB Output is correct
35 Correct 2 ms 644 KB Output is correct
36 Correct 3 ms 644 KB Output is correct
37 Correct 3 ms 644 KB Output is correct
38 Correct 2 ms 644 KB Output is correct
39 Correct 3 ms 644 KB Output is correct
40 Correct 2 ms 644 KB Output is correct
41 Correct 3 ms 644 KB Output is correct
42 Correct 3 ms 644 KB Output is correct
43 Correct 3 ms 644 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 416 KB Output is correct
4 Correct 3 ms 620 KB Output is correct
5 Correct 2 ms 620 KB Output is correct
6 Correct 2 ms 620 KB Output is correct
7 Correct 2 ms 620 KB Output is correct
8 Correct 2 ms 620 KB Output is correct
9 Correct 3 ms 620 KB Output is correct
10 Correct 3 ms 620 KB Output is correct
11 Correct 2 ms 620 KB Output is correct
12 Correct 2 ms 620 KB Output is correct
13 Correct 2 ms 620 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 2 ms 628 KB Output is correct
17 Correct 2 ms 628 KB Output is correct
18 Correct 3 ms 628 KB Output is correct
19 Correct 4 ms 628 KB Output is correct
20 Correct 3 ms 636 KB Output is correct
21 Correct 2 ms 636 KB Output is correct
22 Correct 3 ms 636 KB Output is correct
23 Correct 3 ms 636 KB Output is correct
24 Correct 3 ms 636 KB Output is correct
25 Correct 3 ms 636 KB Output is correct
26 Correct 4 ms 644 KB Output is correct
27 Correct 3 ms 644 KB Output is correct
28 Correct 4 ms 644 KB Output is correct
29 Correct 3 ms 644 KB Output is correct
30 Correct 3 ms 644 KB Output is correct
31 Correct 4 ms 644 KB Output is correct
32 Correct 3 ms 644 KB Output is correct
33 Correct 2 ms 644 KB Output is correct
34 Correct 2 ms 644 KB Output is correct
35 Correct 2 ms 644 KB Output is correct
36 Correct 3 ms 644 KB Output is correct
37 Correct 3 ms 644 KB Output is correct
38 Correct 2 ms 644 KB Output is correct
39 Correct 3 ms 644 KB Output is correct
40 Correct 2 ms 644 KB Output is correct
41 Correct 3 ms 644 KB Output is correct
42 Correct 3 ms 644 KB Output is correct
43 Correct 3 ms 644 KB Output is correct
44 Correct 368 ms 3564 KB Output is correct
45 Correct 391 ms 3564 KB Output is correct
46 Correct 293 ms 3564 KB Output is correct
47 Correct 276 ms 3564 KB Output is correct
48 Correct 452 ms 3640 KB Output is correct
49 Correct 306 ms 3640 KB Output is correct
50 Correct 376 ms 3640 KB Output is correct
51 Correct 274 ms 3640 KB Output is correct
52 Correct 276 ms 3640 KB Output is correct
53 Correct 336 ms 3640 KB Output is correct
54 Correct 325 ms 3640 KB Output is correct
55 Correct 378 ms 3640 KB Output is correct
56 Correct 313 ms 3640 KB Output is correct
57 Correct 309 ms 3640 KB Output is correct
58 Correct 298 ms 3640 KB Output is correct
59 Correct 308 ms 3640 KB Output is correct
60 Correct 378 ms 3640 KB Output is correct
61 Correct 373 ms 3640 KB Output is correct
62 Correct 4 ms 3640 KB Output is correct
63 Correct 6 ms 3640 KB Output is correct
64 Correct 512 ms 3640 KB Output is correct
65 Correct 510 ms 3640 KB Output is correct
66 Correct 340 ms 3640 KB Output is correct
67 Incorrect 452 ms 4128 KB Output isn't correct
68 Halted 0 ms 0 KB -