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답안 #291634

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
291634 2020-09-05T14:56:46 Z TadijaSebez Fences (JOI18_fences) C++11
100 / 100
 714 ms 4328 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;
const ldb eps=1e-9;

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)>0)==(side(P,q.b)>0))return 0;
	line Q=line(q.a,q.b);
	if((side(Q,p.a)>0)==(side(Q,p.b)>0))return 0;
	return 1;
}
bool chk(pt a,int S){return a.x<S-eps&&a.x>-S+eps&&a.y<S-eps&&a.y>-S+eps;}
bool has(ldb l1,ldb r1,ldb l2,ldb r2){return max(l1,l2)+eps<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+eps&&p.a.y<S-eps&&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+eps<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]));
	}
	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:87:8: warning: 'edge::v' will be initialized after [-Wreorder]
   87 |  int f,v;
      |        ^
fences.cpp:86:6: warning:   'long double edge::w' [-Wreorder]
   86 |  ldb w;
      |      ^
fences.cpp:88:2: warning:   when initialized here [-Wreorder]
   88 |  edge(int a,ldb b,int c):v(a),w(b),f(c){}
      |  ^~~~
fences.cpp: In function 'int main()':
fences.cpp:118:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  118 |  scanf("%i %i",&n,&S);
      |  ~~~~~^~~~~~~~~~~~~~~
fences.cpp:121:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  121 |   scanf("%i %i %i %i",&a,&b,&c,&d);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# 결과 실행 시간 메모리 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 1 ms 512 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 0 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 1 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 512 KB Output is correct

Subtask #2
33.0 / 33.0

# 결과 실행 시간 메모리 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 1 ms 512 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 0 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 1 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 512 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 384 KB Output is correct
40 Correct 1 ms 384 KB Output is correct
41 Correct 1 ms 384 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

# 결과 실행 시간 메모리 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 1 ms 512 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 0 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 1 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 512 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 384 KB Output is correct
40 Correct 1 ms 384 KB Output is correct
41 Correct 1 ms 384 KB Output is correct
42 Correct 1 ms 384 KB Output is correct
43 Correct 1 ms 384 KB Output is correct
44 Correct 362 ms 4296 KB Output is correct
45 Correct 335 ms 3956 KB Output is correct
46 Correct 272 ms 2976 KB Output is correct
47 Correct 262 ms 2256 KB Output is correct
48 Correct 407 ms 4328 KB Output is correct
49 Correct 362 ms 3680 KB Output is correct
50 Correct 297 ms 2840 KB Output is correct
51 Correct 267 ms 2408 KB Output is correct
52 Correct 301 ms 2772 KB Output is correct
53 Correct 281 ms 2496 KB Output is correct
54 Correct 288 ms 2812 KB Output is correct
55 Correct 330 ms 2936 KB Output is correct
56 Correct 324 ms 2952 KB Output is correct
57 Correct 303 ms 2644 KB Output is correct
58 Correct 294 ms 2584 KB Output is correct
59 Correct 304 ms 2676 KB Output is correct
60 Correct 296 ms 2788 KB Output is correct
61 Correct 322 ms 3140 KB Output is correct
62 Correct 2 ms 384 KB Output is correct
63 Correct 2 ms 384 KB Output is correct
64 Correct 536 ms 2916 KB Output is correct
65 Correct 714 ms 2768 KB Output is correct
66 Correct 487 ms 2536 KB Output is correct
67 Correct 339 ms 4232 KB Output is correct
68 Correct 338 ms 3928 KB Output is correct
69 Correct 399 ms 3668 KB Output is correct
70 Correct 334 ms 2832 KB Output is correct
71 Correct 381 ms 3496 KB Output is correct
72 Correct 265 ms 2432 KB Output is correct