oj.uz

Submission #56658

# Submission time Handle Problem Language Result Execution time Memory
56658 2018-07-12T05:44:00 Z ksun48 Fences (JOI18_fences) C++14
100 / 100
 404 ms 3436 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;
}
pair<double,int> dist[250][250][2];
void join(int a, int b, int w, double len){
	if(dist[a][b][0].second == w){
		dist[a][b][0].first = min(dist[a][b][0].first, len);
	} else if(dist[a][b][1].second == w){
		dist[a][b][1].first = min(dist[a][b][1].first, len);			
	} else if(len < dist[a][b][1].first){
		dist[a][b][1] = {len, w};
	}
	if(dist[a][b][0] > dist[a][b][1]){
		swap(dist[a][b][0], dist[a][b][1]);
	}
}
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);
	}

	double ans = 200000.0;
	for(int i = 0; i < pts.size(); i++){
		for(int j = 0; j < pts.size(); j++){
			dist[i][j][0] = {200000.0, 0};
			dist[i][j][1] = {200000.0, 1};
		}
	}

	for(int i = 0; i < edges.size(); i++){
		join(edges[i].first, edges[i].second, winds[i], length[i]);
	}
	for(int k = 0; k < pts.size(); k++){
		for(int i = 0; i < pts.size(); i++){
			for(int j = 0; j < pts.size(); j++){
				for(int q = 0; q < 4; q++){
					join(i, j, dist[i][k][q/2].second + dist[k][j][q%2].second, 
						dist[i][k][q/2].first + dist[k][j][q%2].first);
				}
			}
		}
	}
	for(int i = 0; i < pts.size(); i++){
		if(dist[i][i][0].second != 0){
			ans = min(ans, dist[i][i][0].first);
		}
		if(dist[i][i][1].second != 0){
			ans = min(ans, dist[i][i][1].first);
		}
	}
	printf("%.10lf\n", ans);
}

Compilation message

fences.cpp: In function 'int main()':
fences.cpp:110:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < segs.size(); i++){
                 ~~^~~~~~~~~~~~~
fences.cpp:118:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~
fences.cpp:119:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < pts.size(); j++){
                  ~~^~~~~~~~~~~~
fences.cpp:126:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~
fences.cpp:127:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < segs.size(); j++){
                  ~~^~~~~~~~~~~~~
fences.cpp:147:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < segs.size(); i++){
                 ~~^~~~~~~~~~~~~
fences.cpp:158:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pts.size(); i++){
                 ~~^~~~~~~~~~~~
fences.cpp:159:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < pts.size(); j++){
                  ~~^~~~~~~~~~~~
fences.cpp:165:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < edges.size(); i++){
                 ~~^~~~~~~~~~~~~~
fences.cpp:168:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int k = 0; k < pts.size(); k++){
                 ~~^~~~~~~~~~~~
fences.cpp:169:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < pts.size(); i++){
                  ~~^~~~~~~~~~~~
fences.cpp:170:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j = 0; j < pts.size(); j++){
                   ~~^~~~~~~~~~~~
fences.cpp:178:19: 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 2 ms 376 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 408 KB Output is correct
4 Correct 3 ms 468 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 3 ms 516 KB Output is correct
8 Correct 2 ms 516 KB Output is correct
9 Correct 2 ms 516 KB Output is correct
10 Correct 2 ms 516 KB Output is correct
11 Correct 2 ms 548 KB Output is correct
12 Correct 2 ms 548 KB Output is correct
13 Correct 3 ms 576 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 3 ms 676 KB Output is correct
17 Correct 2 ms 676 KB Output is correct
18 Correct 3 ms 676 KB Output is correct
19 Correct 2 ms 676 KB Output is correct
20 Correct 2 ms 676 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 408 KB Output is correct
4 Correct 3 ms 468 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 3 ms 516 KB Output is correct
8 Correct 2 ms 516 KB Output is correct
9 Correct 2 ms 516 KB Output is correct
10 Correct 2 ms 516 KB Output is correct
11 Correct 2 ms 548 KB Output is correct
12 Correct 2 ms 548 KB Output is correct
13 Correct 3 ms 576 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 3 ms 676 KB Output is correct
17 Correct 2 ms 676 KB Output is correct
18 Correct 3 ms 676 KB Output is correct
19 Correct 2 ms 676 KB Output is correct
20 Correct 2 ms 676 KB Output is correct
21 Correct 2 ms 676 KB Output is correct
22 Correct 2 ms 676 KB Output is correct
23 Correct 4 ms 676 KB Output is correct
24 Correct 2 ms 676 KB Output is correct
25 Correct 3 ms 712 KB Output is correct
26 Correct 3 ms 712 KB Output is correct
27 Correct 4 ms 712 KB Output is correct
28 Correct 2 ms 712 KB Output is correct
29 Correct 2 ms 712 KB Output is correct
30 Correct 3 ms 712 KB Output is correct
31 Correct 4 ms 712 KB Output is correct
32 Correct 3 ms 712 KB Output is correct
33 Correct 3 ms 712 KB Output is correct
34 Correct 3 ms 712 KB Output is correct
35 Correct 3 ms 712 KB Output is correct
36 Correct 3 ms 712 KB Output is correct
37 Correct 3 ms 712 KB Output is correct
38 Correct 3 ms 712 KB Output is correct
39 Correct 3 ms 712 KB Output is correct
40 Correct 3 ms 712 KB Output is correct
41 Correct 3 ms 712 KB Output is correct
42 Correct 3 ms 712 KB Output is correct
43 Correct 3 ms 712 KB Output is correct

Subtask #3
49.0 / 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 408 KB Output is correct
4 Correct 3 ms 468 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 3 ms 468 KB Output is correct
7 Correct 3 ms 516 KB Output is correct
8 Correct 2 ms 516 KB Output is correct
9 Correct 2 ms 516 KB Output is correct
10 Correct 2 ms 516 KB Output is correct
11 Correct 2 ms 548 KB Output is correct
12 Correct 2 ms 548 KB Output is correct
13 Correct 3 ms 576 KB Output is correct
14 Correct 2 ms 620 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 3 ms 676 KB Output is correct
17 Correct 2 ms 676 KB Output is correct
18 Correct 3 ms 676 KB Output is correct
19 Correct 2 ms 676 KB Output is correct
20 Correct 2 ms 676 KB Output is correct
21 Correct 2 ms 676 KB Output is correct
22 Correct 2 ms 676 KB Output is correct
23 Correct 4 ms 676 KB Output is correct
24 Correct 2 ms 676 KB Output is correct
25 Correct 3 ms 712 KB Output is correct
26 Correct 3 ms 712 KB Output is correct
27 Correct 4 ms 712 KB Output is correct
28 Correct 2 ms 712 KB Output is correct
29 Correct 2 ms 712 KB Output is correct
30 Correct 3 ms 712 KB Output is correct
31 Correct 4 ms 712 KB Output is correct
32 Correct 3 ms 712 KB Output is correct
33 Correct 3 ms 712 KB Output is correct
34 Correct 3 ms 712 KB Output is correct
35 Correct 3 ms 712 KB Output is correct
36 Correct 3 ms 712 KB Output is correct
37 Correct 3 ms 712 KB Output is correct
38 Correct 3 ms 712 KB Output is correct
39 Correct 3 ms 712 KB Output is correct
40 Correct 3 ms 712 KB Output is correct
41 Correct 3 ms 712 KB Output is correct
42 Correct 3 ms 712 KB Output is correct
43 Correct 3 ms 712 KB Output is correct
44 Correct 284 ms 3432 KB Output is correct
45 Correct 318 ms 3432 KB Output is correct
46 Correct 391 ms 3432 KB Output is correct
47 Correct 379 ms 3432 KB Output is correct
48 Correct 286 ms 3432 KB Output is correct
49 Correct 290 ms 3432 KB Output is correct
50 Correct 329 ms 3432 KB Output is correct
51 Correct 300 ms 3432 KB Output is correct
52 Correct 318 ms 3432 KB Output is correct
53 Correct 404 ms 3432 KB Output is correct
54 Correct 378 ms 3432 KB Output is correct
55 Correct 347 ms 3432 KB Output is correct
56 Correct 288 ms 3432 KB Output is correct
57 Correct 313 ms 3432 KB Output is correct
58 Correct 383 ms 3432 KB Output is correct
59 Correct 285 ms 3432 KB Output is correct
60 Correct 349 ms 3432 KB Output is correct
61 Correct 329 ms 3432 KB Output is correct
62 Correct 4 ms 3432 KB Output is correct
63 Correct 4 ms 3432 KB Output is correct
64 Correct 250 ms 3432 KB Output is correct
65 Correct 349 ms 3432 KB Output is correct
66 Correct 311 ms 3432 KB Output is correct
67 Correct 298 ms 3432 KB Output is correct
68 Correct 224 ms 3436 KB Output is correct
69 Correct 301 ms 3436 KB Output is correct
70 Correct 316 ms 3436 KB Output is correct
71 Correct 396 ms 3436 KB Output is correct
72 Correct 304 ms 3436 KB Output is correct