oj.uz

Submission #291638

# Submission time Handle Problem Language Result Execution time Memory
291638 2020-09-05T14:57:57 Z TadijaSebez Fences (JOI18_fences) C++11
100 / 100
 791 ms 4284 KB 
#include <bits/stdc++.h>
using namespace std;
#define ldb long double
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
const ldb inf=1e9;
 
struct pt{ldb x,y;pt(ldb a=0,ldb b=0):x(a),y(b){}};
bool operator < (pt a,pt b){return mp(a.x,a.y)<mp(b.x,b.y);}
pt operator + (pt a,pt b){return pt(a.x+b.x,a.y+b.y);}
pt operator - (pt a,pt b){return pt(a.x-b.x,a.y-b.y);}
pt operator * (pt a,ldb b){return pt(a.x*b,a.y*b);}
pt operator / (pt a,ldb b){return pt(a.x/b,a.y/b);}
ldb cross(pt a,pt b){return a.x*b.y-a.y*b.x;}
ldb dot(pt a,pt b){return a.x*b.x+a.y*b.y;}
ldb sq(pt a){return dot(a,a);}
ldb abs(pt a){return sqrt(sq(a));}
ldb dist(pt a,pt b){return abs(a-b);}
pt perp(pt a){return pt(-a.y,a.x);}
 
struct line{pt v;ldb c;line(pt a,pt b):v(b-a),c(cross(v,a)){}};
ldb side(line a,pt b){return a.c-cross(a.v,b);}
ldb offs(line a,pt b){return dot(a.v,b);}
bool proj_on(line l,pt a,pt b,pt c){if(offs(l,a)>offs(l,c))swap(a,c);return offs(l,a)<=offs(l,b)&&offs(l,b)<=offs(l,c);}
pt drop(line a,pt b){return b+perp(a.v)/sq(a.v)*side(a,b);}
pt sec(line a,line b){return (b.v*a.c-a.v*b.c)/cross(a.v,b.v);}
 
struct seg{pt a,b;seg(){}seg(pt x,pt y):a(x),b(y){}};
bool operator < (seg p,seg q){return dist(p.a,p.b)<dist(q.a,q.b);}
seg drop(seg p,pt q){
	line P(p.a,p.b);
	if(proj_on(P,p.a,q,p.b))return seg(q,drop(P,q));
	return seg(pt(0,0),pt(inf,0));
}
seg mn_dist(pt p,seg q){
	seg ans=seg(p,q.a);
	ans=min(ans,seg(p,q.b));
	ans=min(ans,drop(q,p));
	return ans;
}
seg mn_dist(seg p,seg q){
	seg ans=seg(p.a,q.a);
	ans=min(ans,seg(p.a,q.b));
	ans=min(ans,seg(p.b,q.a));
	ans=min(ans,seg(p.b,q.b));
	ans=min(ans,drop(p,q.a));
	ans=min(ans,drop(p,q.b));
	ans=min(ans,drop(q,p.a));
	ans=min(ans,drop(q,p.b));
	return ans;
}
bool sec(seg p,seg q){
	line P=line(p.a,p.b);
	if(side(P,q.a)*side(P,q.b)>=0)return 0;
	line Q=line(q.a,q.b);
	if(side(Q,p.a)*side(Q,p.b)>=0)return 0;
	return 1;
}
bool chk(pt a,int S){return a.x<S&&a.x>-S&&a.y<S&&a.y>-S;}
bool has(ldb l1,ldb r1,ldb l2,ldb r2){return max(l1,l2)<min(r1,r2);}
bool chk(seg p,int S){
	if(p.a.x==p.b.x)swap(p.a.x,p.a.y),swap(p.b.x,p.b.y);
	if(p.a.x==p.b.x)return chk(p.a,S);
	if(p.a.x>p.b.x)swap(p.a,p.b);
	if(p.a.y==p.b.y){
		return p.a.y>-S&&p.a.y<S&&has(p.a.x,p.b.x,-S,S);
	}
	ldb lx=(-S-p.a.x)/(p.b.x-p.a.x);
	ldb rx=(S-p.a.x)/(p.b.x-p.a.x);
	if(lx>rx)swap(lx,rx);
	ldb ly=(-S-p.a.y)/(p.b.y-p.a.y);
	ldb ry=(S-p.a.y)/(p.b.y-p.a.y);
	if(ly>ry)swap(ly,ry);
	ldb L=max({lx,ly,(ldb)0});
	ldb R=min({rx,ry,(ldb)1});
	if(L<R)return 1;
	return 0;
}
 
const int N=107;
int n,S;
seg a[N];
struct edge{
	ldb w;
	int f,v;
	edge(int a,ldb b,int c):v(a),w(b),f(c){}
};
vector<edge> E[N*2];
void AddEdge(int u,int v,ldb w,int f){
	E[u].pb(edge(v,w,f));
	E[v].pb(edge(u,w,f));
}
ldb ans=inf,dst[N*2][2];
void Dijkstra(int x,int n){
	priority_queue<pair<ldb,pii>> pq;
	for(int i=1;i<=n;i++)dst[i][0]=dst[i][1]=inf;
	dst[x][0]=0;
	pq.push({0,{x,0}});
	while(pq.size()){
		ldb d=-pq.top().first;
		pii u=pq.top().second;
		pq.pop();
		if(d!=dst[u.first][u.second])continue;
		for(edge e:E[u.first]){
			int v=e.v;
			int f=e.f^u.second;
			if(dst[v][f]>dst[u.first][u.second]+e.w){
				dst[v][f]=dst[u.first][u.second]+e.w;
				pq.push({-dst[v][f],{v,f}});
			}
		}
	}
	ans=min(ans,dst[x][1]);
}
int main(){
	scanf("%i %i",&n,&S);
	for(int i=1;i<=n;i++){
		int a,b,c,d;
		scanf("%i %i %i %i",&a,&b,&c,&d);
		::a[i]=seg(pt(a,b),pt(c,d));
	}
	a[++n]=seg(pt(S,S),pt(S,S));
	a[++n]=seg(pt(S,-S),pt(S,-S));
	a[++n]=seg(pt(-S,S),pt(-S,S));
	a[++n]=seg(pt(-S,-S),pt(-S,-S));
	seg ray=seg(pt(0,0),pt(inf,1));
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++)if(i!=j){
			seg xb=mn_dist(a[i].a,a[j]);
			if(!chk(xb,S)){
				AddEdge(i<<1,j<<1,dist(xb.a,xb.b),sec(ray,seg(a[i].a,xb.b))^sec(ray,seg(xb.b,a[j].a)));
				AddEdge(i<<1,j<<1|1,dist(xb.a,xb.b),sec(ray,seg(a[i].a,xb.b))^sec(ray,seg(xb.b,a[j].b)));
			}
			xb=mn_dist(a[i].b,a[j]);
			if(!chk(xb,S)){
				AddEdge(i<<1|1,j<<1,dist(xb.a,xb.b),sec(ray,seg(a[i].b,xb.b))^sec(ray,seg(xb.b,a[j].a)));
				AddEdge(i<<1|1,j<<1|1,dist(xb.a,xb.b),sec(ray,seg(a[i].b,xb.b))^sec(ray,seg(xb.b,a[j].b)));
			}
		}
		AddEdge(i<<1,i<<1|1,0,sec(ray,a[i]));
		E[i<<1].pb(edge(i<<1|1,0,sec(ray,a[i])));
		E[i<<1|1].pb(edge(i<<1,0,sec(ray,a[i])));
	}
	for(int i=2;i<=n*2+1;i++)Dijkstra(i,n*2+1);
	printf("%.10Lf\n",ans);
	return 0;
}

Compilation message

fences.cpp: In constructor 'edge::edge(int, long double, int)':
fences.cpp:86:8: warning: 'edge::v' will be initialized after [-Wreorder]
   86 |  int f,v;
      |        ^
fences.cpp:85:6: warning:   'long double edge::w' [-Wreorder]
   85 |  ldb w;
      |      ^
fences.cpp:87:2: warning:   when initialized here [-Wreorder]
   87 |  edge(int a,ldb b,int c):v(a),w(b),f(c){}
      |  ^~~~
fences.cpp: In function 'int main()':
fences.cpp:117:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  117 |  scanf("%i %i",&n,&S);
      |  ~~~~~^~~~~~~~~~~~~~~
fences.cpp:120:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  120 |   scanf("%i %i %i %i",&a,&b,&c,&d);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 1 ms 384 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 1 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 1 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 1 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 1 ms 384 KB Output is correct
29 Correct 1 ms 384 KB Output is correct
30 Correct 1 ms 384 KB Output is correct
31 Correct 1 ms 384 KB Output is correct
32 Correct 1 ms 384 KB Output is correct
33 Correct 1 ms 384 KB Output is correct
34 Correct 1 ms 384 KB Output is correct
35 Correct 1 ms 384 KB Output is correct
36 Correct 1 ms 384 KB Output is correct
37 Correct 1 ms 384 KB Output is correct
38 Correct 1 ms 384 KB Output is correct
39 Correct 1 ms 400 KB Output is correct
40 Correct 1 ms 384 KB Output is correct
41 Correct 1 ms 360 KB Output is correct
42 Correct 1 ms 384 KB Output is correct
43 Correct 1 ms 384 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 384 KB Output is correct
20 Correct 1 ms 384 KB Output is correct
21 Correct 1 ms 384 KB Output is correct
22 Correct 1 ms 384 KB Output is correct
23 Correct 1 ms 384 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 1 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 1 ms 384 KB Output is correct
28 Correct 1 ms 384 KB Output is correct
29 Correct 1 ms 384 KB Output is correct
30 Correct 1 ms 384 KB Output is correct
31 Correct 1 ms 384 KB Output is correct
32 Correct 1 ms 384 KB Output is correct
33 Correct 1 ms 384 KB Output is correct
34 Correct 1 ms 384 KB Output is correct
35 Correct 1 ms 384 KB Output is correct
36 Correct 1 ms 384 KB Output is correct
37 Correct 1 ms 384 KB Output is correct
38 Correct 1 ms 384 KB Output is correct
39 Correct 1 ms 400 KB Output is correct
40 Correct 1 ms 384 KB Output is correct
41 Correct 1 ms 360 KB Output is correct
42 Correct 1 ms 384 KB Output is correct
43 Correct 1 ms 384 KB Output is correct
44 Correct 367 ms 4284 KB Output is correct
45 Correct 330 ms 3776 KB Output is correct
46 Correct 292 ms 2688 KB Output is correct
47 Correct 268 ms 2548 KB Output is correct
48 Correct 397 ms 4276 KB Output is correct
49 Correct 381 ms 3844 KB Output is correct
50 Correct 307 ms 2692 KB Output is correct
51 Correct 275 ms 2476 KB Output is correct
52 Correct 309 ms 2712 KB Output is correct
53 Correct 302 ms 2560 KB Output is correct
54 Correct 341 ms 2768 KB Output is correct
55 Correct 326 ms 2872 KB Output is correct
56 Correct 383 ms 3008 KB Output is correct
57 Correct 316 ms 2652 KB Output is correct
58 Correct 305 ms 2628 KB Output is correct
59 Correct 411 ms 2640 KB Output is correct
60 Correct 375 ms 2700 KB Output is correct
61 Correct 439 ms 3056 KB Output is correct
62 Correct 2 ms 384 KB Output is correct
63 Correct 2 ms 384 KB Output is correct
64 Correct 566 ms 2864 KB Output is correct
65 Correct 791 ms 2628 KB Output is correct
66 Correct 501 ms 2676 KB Output is correct
67 Correct 347 ms 3936 KB Output is correct
68 Correct 337 ms 3924 KB Output is correct
69 Correct 426 ms 3392 KB Output is correct
70 Correct 436 ms 2832 KB Output is correct
71 Correct 392 ms 3460 KB Output is correct
72 Correct 259 ms 2560 KB Output is correct