题目大意:给定一张平面图,求对偶图的最小树形图
这题TM考了我两遍!!两遍!!我拿了两遍MST的60分!
世界你赢了 你逼着我学了朱刘算法233
#include
#include
#include
#include
#include
#include
#define M 3030
#define INF 0x3f3f3f3f
using namespace std;
struct Point{
int x,y;
Point() {}
Point(int _,int __):x(_),y(__) {}
friend istream& operator >> (istream &_,Point &p)
{
scanf("%d%d",&p.x,&p.y);
return _;
}
friend Point operator - (const Point &p1,const Point &p2)
{
return Point(p1.x-p2.x,p1.y-p2.y);
}
friend double Arctan2(const Point &p)
{
return atan2(p.y,p.x);
}
}points[M];
struct List{
List *another;
int to,len,belong;
double alpha;
List() {}
List(int _,int __,double ___):
another(0x0),to(_),len(__),belong(0),alpha(___) {}
};
int n,m,cnt=1;
vector a[M];
bool Compare(const List *x,const List *y)
{
return x->alpha < y->alpha ;
}
void Add(int x,int y,int t1,int t2)
{
if(!t1) t1=INF;
if(!t2) t2=INF;
Point p=points[y]-points[x];
List *temp1=new List(y,t1,Arctan2(p));
List *temp2=new List(x,t2,Arctan2(Point(0,0)-p));
temp1->another=temp2;
temp2->another=temp1;
a[x].push_back(temp1);
a[y].push_back(temp2);
}
void DFS(int x,List *from,int aim)
{
from->belong=cnt;
if(x==aim)
return ;
vector::iterator it=lower_bound(a[x].begin(),a[x].end(),from->another,Compare);
it++;if(it==a[x].end()) it=a[x].begin();
DFS((*it)->to,*it,aim);
}
namespace Dual_Graph{
struct edge{
int x,y,z;
edge() {}
edge(int _,int __,int ___):
x(_),y(__),z(___) {}
}edges[100100];
int n,m;
void Add(int x,int y,int z)
{
++m;
edges[m].x=x;
edges[m].y=y;
edges[m].z=z;
}
int DMST()
{
static int f[M],from[M],v[M],T;
static bool deleted[M];
int i,j,re=0;
while(1)
{
memset(f,0x3f,sizeof f);
memset(from,0,sizeof from);
for(i=1;i<=m;i++)
if(f[edges[i].y]>edges[i].z)
{
f[edges[i].y]=edges[i].z;
from[edges[i].y]=edges[i].x;
}
for(i=2;i<=n;i++)
if(!deleted[i])
if(f[i]==INF)
return -1;
memset(v,0,sizeof v);
for(i=2;i<=n;i++)
if(!deleted[i])
{
for(++T,j=i;j!=1&&!v[j];j=from[j])
v[j]=T;
if(v[j]==T)
break;
}
if(i==n+1)
{
for(i=2;i<=n;i++)
if(!deleted[i])
re+=f[i];
return re;
}
memset(v,0,sizeof v);
i=j;do{
i=from[i];
re+=f[i];
v[i]=true;
deleted[i]=true;
}while(i!=j);
deleted[j]=false;
int cnt=0;
for(i=1;i<=m;i++)
{
if(!v[edges[i].x]&&!v[edges[i].y])
edges[++cnt]=edges[i];
else if(v[edges[i].x]&&v[edges[i].y])
continue;
else if(v[edges[i].x])
edges[++cnt]=edge(j,edges[i].y,edges[i].z);
else
edges[++cnt]=edge(edges[i].x,j,edges[i].z-f[edges[i].y]);
}
m=cnt;
}
}
}
int main()
{
//freopen("square.in","r",stdin);
//freopen("square.out","w",stdout);
int i,x,y,t1,t2;
cin>>n>>m;
for(i=1;i<=n;i++)
cin>>points[i];
for(i=1;i<=m;i++)
{
scanf("%d%d%d%d",&x,&y,&t1,&t2);
Add(x,y,t1,t2);
}
for(i=1;i<=n;i++)
sort(a[i].begin(),a[i].end(),Compare);
for(x=1;x<=n;x++)
{
vector::iterator it;
for(it=a[x].begin();it!=a[x].end();it++)
if(!(*it)->belong)
++cnt,DFS((*it)->to,*it,x);
}
for(x=1;x<=n;x++)
{
vector::iterator it;
for(it=a[x].begin();it!=a[x].end();it++)
if((*it)->len!=INF)
Dual_Graph::Add((*it)->another->belong,(*it)->belong,(*it)->len);
}
Dual_Graph::n=cnt;
for(i=2;i<=cnt;i++)
Dual_Graph::Add(1,i,0x1010101);
cout<