oj.uz

Submission #44664

# Submission time Handle Problem Language Result Execution time Memory
44664 2018-04-04T14:35:22 Z zscoder Fences (JOI18_fences) C++17
100 / 100
 538 ms 3720 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
 
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<int> vi;
typedef long double ld; 
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<ll>::iterator sit;
typedef map<ll,ll>::iterator mit;

const double eps=1e-8;
const double pi=acos(-1.0);
const double inf=1e20;
const int maxp=111111;
int dblcmp(double d)
{
    if (fabs(d)<eps)return 0;
    return d>eps?1:-1;
}
inline double sqr(double x){return x*x;}
struct point 
{
    double x,y;
    point(){}
    point(double _x,double _y):
    x(_x),y(_y){};
    void input()
    {
        scanf("%lf%lf",&x,&y);
    }
    void output()
    {
        printf("%.2f %.2f\n",x,y);
    }
    bool operator==(point a)const
    {
        return dblcmp(a.x-x)==0&&dblcmp(a.y-y)==0;
    }
    bool operator<(point a)const
    {
        return dblcmp(a.x-x)==0?dblcmp(y-a.y)<0:x<a.x;
    }
    double len()
    {
        return hypot(x,y);
    }
    double len2()
    {
        return x*x+y*y;
    }
    double distance(point p)
    {
        return hypot(x-p.x,y-p.y);
    }
    point add(point p)
    {
        return point(x+p.x,y+p.y);
    }
    point sub(point p)
    {
        return point(x-p.x,y-p.y);
    }
    point mul(double b)
    {
        return point(x*b,y*b);
    }
    point div(double b)
    {
        return point(x/b,y/b);
    }
    double dot(point p)
    {
        return x*p.x+y*p.y;
    }
    double det(point p)
    {
        return x*p.y-y*p.x;
    }
    double rad(point a,point b)
    {
        point p=*this;
        return fabs(atan2(fabs(a.sub(p).det(b.sub(p))),a.sub(p).dot(b.sub(p))));
    }
    point trunc(double r)
    {
        double l=len();
        if (!dblcmp(l))return *this;
        r/=l;
        return point(x*r,y*r);
    }
    point rotleft()
    {
        return point(-y,x);
    }
    point rotright()
    {
        return point(y,-x);
    }
    point rotate(point p,double angle)//绕点p逆时针旋转angle角度 
    {
        point v=this->sub(p);
        double c=cos(angle),s=sin(angle);
        return point(p.x+v.x*c-v.y*s,p.y+v.x*s+v.y*c);
    }        
};

struct line 
{
    point a,b;
    line(){}
    line(point _a,point _b)
    {
        a=_a;
        b=_b;
    }
    bool operator==(line v)
    {
        return (a==v.a)&&(b==v.b);
    }
    //倾斜角angle 
    line(point p,double angle)
    {
        a=p;
        if (dblcmp(angle-pi/2)==0)
        {
            b=a.add(point(0,1));
        }
        else 
        {
            b=a.add(point(1,tan(angle)));
        }
    }       
    //ax+by+c=0
    line(double _a,double _b,double _c)
    {
        if (dblcmp(_a)==0)
        {
            a=point(0,-_c/_b);
            b=point(1,-_c/_b);
        }
        else if (dblcmp(_b)==0)
        {
            a=point(-_c/_a,0);
            b=point(-_c/_a,1);
        }
        else 
        {
            a=point(0,-_c/_b);
            b=point(1,(-_c-_a)/_b);
        }
    }
    void input()
    {
        a.input();
        b.input();
    }
    void adjust()
    {
        if (b<a)swap(a,b);
    }
    double length()
    {
        return a.distance(b);
    }
    double angle()//直线倾斜角 0<=angle<180 
    {
        double k=atan2(b.y-a.y,b.x-a.x);
        if (dblcmp(k)<0)k+=pi;
        if (dblcmp(k-pi)==0)k-=pi;
        return k;
    }
    //点和线段关系
    //1 在逆时针
    //2 在顺时针
    //3 平行
    int relation(point p)
    {
        int c=dblcmp(p.sub(a).det(b.sub(a)));
        if (c<0)return 1;
        if (c>0)return 2;
        return 3;
    }
    bool pointonseg(point p)
    {
        return dblcmp(p.sub(a).det(b.sub(a)))==0&&dblcmp(p.sub(a).dot(p.sub(b)))<=0;
    }
    bool parallel(line v)
    {
        return dblcmp(b.sub(a).det(v.b.sub(v.a)))==0;
    }
    //2 规范相交
    //1 非规范相交
    //0 不相交 
    int segcrossseg(line v)
    {
        int d1=dblcmp(b.sub(a).det(v.a.sub(a)));
        int d2=dblcmp(b.sub(a).det(v.b.sub(a)));
        int d3=dblcmp(v.b.sub(v.a).det(a.sub(v.a)));
        int d4=dblcmp(v.b.sub(v.a).det(b.sub(v.a)));
        if ((d1^d2)==-2&&(d3^d4)==-2)return 2;
        return (d1==0&&dblcmp(v.a.sub(a).dot(v.a.sub(b)))<=0||
                d2==0&&dblcmp(v.b.sub(a).dot(v.b.sub(b)))<=0||
                d3==0&&dblcmp(a.sub(v.a).dot(a.sub(v.b)))<=0||
                d4==0&&dblcmp(b.sub(v.a).dot(b.sub(v.b)))<=0);        
    }        
    int linecrossseg(line v)//*this seg v line
    {
        int d1=dblcmp(b.sub(a).det(v.a.sub(a)));
        int d2=dblcmp(b.sub(a).det(v.b.sub(a)));
        if ((d1^d2)==-2)return 2;
        return (d1==0||d2==0);
    }
    //0 平行
    //1 重合
    //2 相交 
    int linecrossline(line v)
    {
        if ((*this).parallel(v))
        {
            return v.relation(a)==3;
        }
        return 2;
    }
    point crosspoint(line v)
    {
        double a1=v.b.sub(v.a).det(a.sub(v.a));
        double a2=v.b.sub(v.a).det(b.sub(v.a));
        return point((a.x*a2-b.x*a1)/(a2-a1),(a.y*a2-b.y*a1)/(a2-a1));
    }
    double dispointtoline(point p)
    {
        return fabs(p.sub(a).det(b.sub(a)))/length();
    }
    double dispointtoseg(point p)
    {
        if (dblcmp(p.sub(b).dot(a.sub(b)))<0||dblcmp(p.sub(a).dot(b.sub(a)))<0)
        {
            return min(p.distance(a),p.distance(b));
        }
        return dispointtoline(p);
    }
    point lineprog(point p)
    {
        return a.add(b.sub(a).mul(b.sub(a).dot(p.sub(a))/b.sub(a).len2()));
    }
    point symmetrypoint(point p)
    {
        point q=lineprog(p);
        return point(2*q.x-p.x,2*q.y-p.y);
    }   
};

bool clash(line a, line b)
{
	return (a.segcrossseg(b)!=0);
}

bool clash2(line a, line b)
{
	if(a.segcrossseg(b)!=0)
	{
		if(a.parallel(b)) return false;
		point tmp = a.crosspoint(b);
		////cerr<<"CROSSPOINT : \n"<<a.a.x<<' '<<a.a.y<<' '<<a.b.x<<' '<<a.b.y<<'\n'<<b.a.x<<' '<<b.a.y<<' '<<b.b.x<<' '<<b.b.y<<'\n'<<tmp.x<<' '<<tmp.y<<'\n';
		if(b.a == tmp || b.b == tmp || a.a == tmp || a.b == tmp) return false;
		return true;
	}
	return false;
}

const int N = 422;
point a[N+11];
point b[N+11];
point square[4];
ld dist[N+11][N+11];
line ray;

void amin(ld &x, ld y)
{
	x=min(x,y);
}

void add_edge(int u, int v, ld d, bool intersect)
{
	u*=2; v*=2;
	if(intersect) //if u-v intersects the ray
	{
		for(int i=0;i<2;i++)
		{
			amin(dist[u][v^1],d); amin(dist[u^1][v],d);
			swap(u,v);
		}
	}
	else
	{
		for(int i=0;i<2;i++)
		{
			amin(dist[u][v],d); amin(dist[u^1][v^1],d);
			swap(u,v);
		}
	}
}
int n,s;
bool good(point a, point b)
{
	for(int i=0;i<4;i++)
	{
		if(clash2(line(a,b), line(square[i],square[(i+1)%4]))) return false;
	}
	point tmp = point((a.x+b.x)*0.5, (a.y+b.y)*0.5); //check if the line segment lies within the square
	if(tmp.x>-s&&tmp.x<s&&tmp.y>-s&&tmp.y<s) return false;
	return true;
}

ld getdist(point a, point b)
{
	return a.distance(b);
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin>>n>>s; ld ans = s*8;
	square[0] = point(-s,-s); 
	square[1] = point(-s, s);
	square[2] = point(s,s);
	square[3] = point(s,-s);
	ray = line(point(0,0), point(1,2018));
	for(int i=0;i<n;i++)
	{
		cin>>a[i].x>>a[i].y>>b[i].x>>b[i].y;
	}
	for(int i=0;i<4;i++)
	{
		a[n] = square[i];
		b[n++] = square[i];
	}
	for(int i=0;i<N;i++)
	{
		for(int j=0;j<N;j++)
		{
			dist[i][j]=(i==j?0.0:ld(1e12));
		}
	}
	for(int i=0;i<n;i++)
	{
		add_edge(i,i+n,0,clash(ray, line(a[i], b[i])));
		for(int j=i+1;j<n;j++)
		{
			if(good(a[i],a[j])) 
			{
				//cerr<<"DO ZZZ "<<i<<' '<<j<<'\n';
				//cerr<<"LINE : "<<a[i].x<<' '<<a[i].y<<' '<<a[j].x<<' '<<a[j].y<<'\n';
				add_edge(i,j,getdist(a[i],a[j]),clash(ray,line(a[i],a[j])));
			}
			if(good(a[i],b[j])) 
			{
				//cerr<<"DO ZZZ "<<i<<' '<<j+n<<'\n';
				//cerr<<"LINE : "<<a[i].x<<' '<<a[i].y<<' '<<b[j].x<<' '<<b[j].y<<'\n';
				add_edge(i,j+n,getdist(a[i],b[j]),clash(ray,line(a[i],b[j])));
			}
			if(good(b[i],a[j])) 
			{
				//cerr<<"DO ZZZ "<<i+n<<' '<<j<<'\n';
				//cerr<<"LINE : "<<b[i].x<<' '<<b[i].y<<' '<<a[j].x<<' '<<a[j].y<<'\n';
				add_edge(i+n,j,getdist(b[i],a[j]),clash(ray,line(b[i],a[j])));
			}
			if(good(b[i],b[j])) 
			{
				//cerr<<"DO ZZZ "<<i+n<<' '<<j+n<<'\n';
				//cerr<<"LINE : "<<b[i].x<<' '<<b[i].y<<' '<<b[j].x<<' '<<b[j].y<<'\n';
				add_edge(i+n,j+n,getdist(b[i],b[j]),clash(ray,line(b[i],b[j])));
			}
			for(int z=0;z<2;z++)
			{
				point foot = line(a[j], b[j]).lineprog(a[i]);
				if(line(a[j], b[j]).pointonseg(foot) && good(foot, a[i]))
				{
					//cerr<<"DO "<<i<<' '<<j<<' '<<j+n<<'\n';
					add_edge(i, j, getdist(a[i], foot), clash(ray, line(a[i], foot))^clash(ray, line(a[j], foot)));
					add_edge(i, j + n, getdist(a[i], foot), clash(ray, line(a[i], foot))^clash(ray, line(b[j], foot)));
				}
				foot = line(a[j], b[j]).lineprog(b[i]);
				if(line(a[j], b[j]).pointonseg(foot) && good(foot, b[i]))
				{
					//cerr<<"DO "<<i+n<<' '<<j<<' '<<j+n<<'\n';
					add_edge(i + n, j, getdist(b[i], foot), clash(ray, line(b[i], foot))^clash(ray, line(a[j], foot)));
					add_edge(i + n, j + n, getdist(b[i], foot), clash(ray, line(b[i], foot))^clash(ray, line(b[j], foot)));
				}
				swap(i,j);
			}
		}
	}
	for(int i=0;i<4*n;i++)
	{
		for(int j=0;j<4*n;j++)
		{
			//if(dist[i][j]<ld(1e12)) cerr<<"("<<i/2<<","<<i%2<<") ("<<j/2<<","<<j%2<<") "<<dist[i][j]<<'\n';
		}
	}
	for(int k=0;k<4*n;k++)
	{
		for(int i=0;i<4*n;i++)
		{
			for(int j=0;j<4*n;j++)
			{
				amin(dist[i][j],dist[i][k]+dist[k][j]);
			}
		}
	}
	for(int i=0;i<2*n;i++)
	{
		//cerr<<"DIST : "<<i*2<<' '<<i*2+1<<' '<<dist[i*2][i*2+1]<<'\n';
		amin(ans, dist[i*2][i*2+1]);
	}
	cout<<fixed<<setprecision(10)<<ans<<'\n';
}

Compilation message

fences.cpp: In member function 'int line::segcrossseg(line)':
fences.cpp:213:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         return (d1==0&&dblcmp(v.a.sub(a).dot(v.a.sub(b)))<=0||
                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fences.cpp:215:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                 d3==0&&dblcmp(a.sub(v.a).dot(a.sub(v.b)))<=0||
                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fences.cpp:216:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                 d4==0&&dblcmp(b.sub(v.a).dot(b.sub(v.b)))<=0);        
                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3192 KB Output is correct
2 Correct 4 ms 3304 KB Output is correct
3 Correct 5 ms 3372 KB Output is correct
4 Correct 5 ms 3372 KB Output is correct
5 Correct 4 ms 3488 KB Output is correct
6 Correct 4 ms 3488 KB Output is correct
7 Correct 4 ms 3488 KB Output is correct
8 Correct 5 ms 3488 KB Output is correct
9 Correct 4 ms 3488 KB Output is correct
10 Correct 4 ms 3488 KB Output is correct
11 Correct 4 ms 3488 KB Output is correct
12 Correct 4 ms 3488 KB Output is correct
13 Correct 4 ms 3488 KB Output is correct
14 Correct 4 ms 3488 KB Output is correct
15 Correct 4 ms 3488 KB Output is correct
16 Correct 4 ms 3488 KB Output is correct
17 Correct 4 ms 3488 KB Output is correct
18 Correct 4 ms 3488 KB Output is correct
19 Correct 4 ms 3488 KB Output is correct
20 Correct 4 ms 3488 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3192 KB Output is correct
2 Correct 4 ms 3304 KB Output is correct
3 Correct 5 ms 3372 KB Output is correct
4 Correct 5 ms 3372 KB Output is correct
5 Correct 4 ms 3488 KB Output is correct
6 Correct 4 ms 3488 KB Output is correct
7 Correct 4 ms 3488 KB Output is correct
8 Correct 5 ms 3488 KB Output is correct
9 Correct 4 ms 3488 KB Output is correct
10 Correct 4 ms 3488 KB Output is correct
11 Correct 4 ms 3488 KB Output is correct
12 Correct 4 ms 3488 KB Output is correct
13 Correct 4 ms 3488 KB Output is correct
14 Correct 4 ms 3488 KB Output is correct
15 Correct 4 ms 3488 KB Output is correct
16 Correct 4 ms 3488 KB Output is correct
17 Correct 4 ms 3488 KB Output is correct
18 Correct 4 ms 3488 KB Output is correct
19 Correct 4 ms 3488 KB Output is correct
20 Correct 4 ms 3488 KB Output is correct
21 Correct 4 ms 3488 KB Output is correct
22 Correct 5 ms 3488 KB Output is correct
23 Correct 5 ms 3488 KB Output is correct
24 Correct 4 ms 3488 KB Output is correct
25 Correct 5 ms 3488 KB Output is correct
26 Correct 5 ms 3488 KB Output is correct
27 Correct 4 ms 3488 KB Output is correct
28 Correct 13 ms 3488 KB Output is correct
29 Correct 4 ms 3488 KB Output is correct
30 Correct 5 ms 3488 KB Output is correct
31 Correct 5 ms 3488 KB Output is correct
32 Correct 5 ms 3488 KB Output is correct
33 Correct 5 ms 3488 KB Output is correct
34 Correct 4 ms 3488 KB Output is correct
35 Correct 4 ms 3488 KB Output is correct
36 Correct 4 ms 3488 KB Output is correct
37 Correct 5 ms 3488 KB Output is correct
38 Correct 4 ms 3488 KB Output is correct
39 Correct 4 ms 3488 KB Output is correct
40 Correct 4 ms 3488 KB Output is correct
41 Correct 4 ms 3488 KB Output is correct
42 Correct 4 ms 3488 KB Output is correct
43 Correct 6 ms 3488 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3192 KB Output is correct
2 Correct 4 ms 3304 KB Output is correct
3 Correct 5 ms 3372 KB Output is correct
4 Correct 5 ms 3372 KB Output is correct
5 Correct 4 ms 3488 KB Output is correct
6 Correct 4 ms 3488 KB Output is correct
7 Correct 4 ms 3488 KB Output is correct
8 Correct 5 ms 3488 KB Output is correct
9 Correct 4 ms 3488 KB Output is correct
10 Correct 4 ms 3488 KB Output is correct
11 Correct 4 ms 3488 KB Output is correct
12 Correct 4 ms 3488 KB Output is correct
13 Correct 4 ms 3488 KB Output is correct
14 Correct 4 ms 3488 KB Output is correct
15 Correct 4 ms 3488 KB Output is correct
16 Correct 4 ms 3488 KB Output is correct
17 Correct 4 ms 3488 KB Output is correct
18 Correct 4 ms 3488 KB Output is correct
19 Correct 4 ms 3488 KB Output is correct
20 Correct 4 ms 3488 KB Output is correct
21 Correct 4 ms 3488 KB Output is correct
22 Correct 5 ms 3488 KB Output is correct
23 Correct 5 ms 3488 KB Output is correct
24 Correct 4 ms 3488 KB Output is correct
25 Correct 5 ms 3488 KB Output is correct
26 Correct 5 ms 3488 KB Output is correct
27 Correct 4 ms 3488 KB Output is correct
28 Correct 13 ms 3488 KB Output is correct
29 Correct 4 ms 3488 KB Output is correct
30 Correct 5 ms 3488 KB Output is correct
31 Correct 5 ms 3488 KB Output is correct
32 Correct 5 ms 3488 KB Output is correct
33 Correct 5 ms 3488 KB Output is correct
34 Correct 4 ms 3488 KB Output is correct
35 Correct 4 ms 3488 KB Output is correct
36 Correct 4 ms 3488 KB Output is correct
37 Correct 5 ms 3488 KB Output is correct
38 Correct 4 ms 3488 KB Output is correct
39 Correct 4 ms 3488 KB Output is correct
40 Correct 4 ms 3488 KB Output is correct
41 Correct 4 ms 3488 KB Output is correct
42 Correct 4 ms 3488 KB Output is correct
43 Correct 6 ms 3488 KB Output is correct
44 Correct 460 ms 3512 KB Output is correct
45 Correct 476 ms 3580 KB Output is correct
46 Correct 448 ms 3580 KB Output is correct
47 Correct 456 ms 3620 KB Output is correct
48 Correct 444 ms 3620 KB Output is correct
49 Correct 472 ms 3620 KB Output is correct
50 Correct 449 ms 3632 KB Output is correct
51 Correct 442 ms 3632 KB Output is correct
52 Correct 452 ms 3644 KB Output is correct
53 Correct 444 ms 3708 KB Output is correct
54 Correct 464 ms 3708 KB Output is correct
55 Correct 456 ms 3708 KB Output is correct
56 Correct 447 ms 3708 KB Output is correct
57 Correct 438 ms 3708 KB Output is correct
58 Correct 461 ms 3708 KB Output is correct
59 Correct 449 ms 3708 KB Output is correct
60 Correct 447 ms 3708 KB Output is correct
61 Correct 459 ms 3708 KB Output is correct
62 Correct 6 ms 3708 KB Output is correct
63 Correct 5 ms 3708 KB Output is correct
64 Correct 406 ms 3708 KB Output is correct
65 Correct 526 ms 3708 KB Output is correct
66 Correct 409 ms 3708 KB Output is correct
67 Correct 401 ms 3708 KB Output is correct
68 Correct 439 ms 3708 KB Output is correct
69 Correct 538 ms 3712 KB Output is correct
70 Correct 372 ms 3712 KB Output is correct
71 Correct 421 ms 3720 KB Output is correct
72 Correct 447 ms 3720 KB Output is correct