BZOJ 2960 跨平面 对偶图+朱刘算法

标签：bzoj   bzoj2960   对偶图   朱刘算法   

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 <cmath>
#include <vector>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#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<List*> 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<List*>::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<List*>::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<List*>::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<<Dual_Graph::DMST()-0x1010101<<endl;
	return 0;
}

BZOJ 2960 跨平面 对偶图+朱刘算法

标签：bzoj   bzoj2960   对偶图   朱刘算法   

原文地址：http://blog.csdn.net/popoqqq/article/details/45044715