hdu 1558 Segment set 线段相交+并查集

Segment set

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Problem Description
A segment and all segments which are connected with it compose a segment set. The size of a segment set is the number of segments in it. The problem is to find the size of some segment set.

hdu 1558 Segment set 线段相交+并查集

 
Input
In the first line there is an integer t - the number of test case. For each test case in first line there is an integer n (n<=1000) - the number of commands.

There are two different commands described in different format shown below:

P x1 y1 x2 y2 - paint a segment whose coordinates of the two endpoints are (x1,y1),(x2,y2).
Q k - query the size of the segment set which contains the k-th segment.

k is between 1 and the number of segments in the moment. There is no segment in the plane at first, so the first command is always a P-command.

 
Output
For each Q-command, output the answer. There is a blank line between test cases.
 
Sample Input
1
10
P 1.00 1.00 4.00 2.00
P 1.00 -2.00 8.00 4.00
Q 1
P 2.00 3.00 3.00 1.00
Q 1
Q 3
P 1.00 4.00 8.00 2.00
Q 2
P 3.00 3.00 6.00 -2.00
Q 5
 
Sample Output
1
2
2
2
5
 
Author
LL
 
Source
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<queue>
#include<algorithm>
#include<stack>
#include<cstring>
#include<vector>
#include<list>
#include<bitset>
#include<set>
#include<map>
#include<time.h>
using namespace std;
#define LL long long
#define bug(x) cout<<"bug"<<x<<endl;
const int N=1e3+,M=2e6+,inf=1e9+;
const LL INF=1e18+,mod=,MOD=;
const double eps=1e-,pi=(*atan(1.0)); int sgn(double x)
{
if(fabs(x) < eps)return ;
if(x < )return -;
else return ;
}
struct Point
{
double x,y;
Point() {}
Point(double _x,double _y)
{
x = _x;
y = _y;
}
Point operator -(const Point &b)const
{
return Point(x - b.x,y - b.y);
}
//叉积
double operator ^(const Point &b)const
{
return x*b.y - y*b.x;
}
//点积
double operator *(const Point &b)const
{
return x*b.x + y*b.y;
}
//绕原点旋转角度B(弧度值),后x,y的变化
void transXY(double B)
{
double tx = x,ty = y;
x= tx*cos(B) - ty*sin(B);
y= tx*sin(B) + ty*cos(B);
}
};
struct Line
{
Point s,e;
Line() {}
Line(Point _s,Point _e)
{
s = _s;
e = _e;
}
//两直线相交求交点 //第一个值为0表示直线重合,为1表示平行,为0表示相交,为2是相交 //只有第一个值为2时,交点才有意义
pair<int,Point> operator &(const Line &b)const
{
Point res = s;
if(sgn((s-e)^(b.s-b.e)) == )
{
if(sgn((s-b.e)^(b.s-b.e)) == ) return make_pair(,res);//重合
else return make_pair(,res);//平行
}
double t = ((s-b.s)^(b.s-b.e))/((s-e)^(b.s-b.e));
res.x += (e.x-s.x)*t;
res.y += (e.y-s.y)*t;
return make_pair(,res);
}
};
bool inter(Line l1,Line l2)
{
return
max(l1.s.x,l1.e.x) >= min(l2.s.x,l2.e.x) &&
max(l2.s.x,l2.e.x) >= min(l1.s.x,l1.e.x) &&
max(l1.s.y,l1.e.y) >= min(l2.s.y,l2.e.y) &&
max(l2.s.y,l2.e.y) >= min(l1.s.y,l1.e.y) &&
sgn((l2.s-l1.e)^(l1.s-l1.e))*sgn((l2.e-l1.e)^(l1.s-l1.e)) <= &&
sgn((l1.s-l2.e)^(l2.s-l2.e))*sgn((l1.e-l2.e)^(l2.s-l2.e)) <= ;
}
char ch[N];
int fa[N],si[N];
int Find(int x)
{
return x==fa[x]?x:fa[x]=Find(fa[x]);
}
void update(int u,int v)
{
int x=Find(u);
int z=Find(v);
if(x!=z)
{
fa[x]=z;
si[z]+=si[x];
}
}
Line a[N];
int main()
{
int T,cas=;
scanf("%d",&T);
while(T--)
{
if(cas)printf("\n");
cas++;
int cnt=;
for(int i=;i<=;i++)
fa[i]=i,si[i]=;
int q;
scanf("%d",&q);
while(q--)
{
scanf("%s",ch);
if(ch[]=='Q')
{
int x;
scanf("%d",&x);
int f=Find(x);
printf("%d\n",si[f]);
}
else
{
double x1,y1,x2,y2;
scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
Point s(x1,y1),e(x2,y2);
a[++cnt]=Line(s,e);
for(int i=;i<cnt;i++)
if(inter(a[i],a[cnt]))update(i,cnt);
}
}
}
return ;
}
上一篇:Long转Date/页面自定义标签


下一篇:优秀API设计的十大原则