poj 2125

最小点权覆盖。

注意入边，出边不要搞反了。

代码:

#include<iostream>
#include<fstream>
#include<queue>


using namespace std;

int n;
int d[210];
int flow;
int v[210];


typedef struct e{
	int data;
	int f,c;
	e *next,*opt;
}e;

e edge[210];

int build(){
	int i,j,k;
	queue<int> q;
	q.push(1);
	memset(d,0,sizeof(d));
	d[1]=1;
	while(!q.empty())
	{
		i=q.front();
		q.pop();
		e *p=edge[i].next;
		while(p)
		{
			j=p->data;
			if(d[j]==0&&p->c>p->f)
			{
				d[j]=d[i]+1;
				if(j==n) return 1;
				q.push(j);
			}
			p=p->next;
		}
	}
	return 0;
}

int find(int m,int  minw){
	int i,k;
	int j;
	if(m==n) return minw;
	v[m]=1;
	e *p=edge[m].next;
	while(p)
	{
		i=p->data;
		if(p->c>p->f&&d[i]==d[m]+1&&v[i]==0)
		{
			j=find(i,min(minw,p->c-p->f));
			if(j)
			{
				p->f+=j;
				p->opt->f=p->f*(-1);
				return j;
			}
		}
		p=p->next;
	}
	return 0;
}


int solve(){
	int j;
	int k;
	 flow=0;
	int i;
	while(build())
		while(1){
			memset(v,0,sizeof(v));
			i=10000000;
			k=find(1,i);
			flow+=k;
			if(k==0) break;
		}
	return flow;
}

void dfs(int s){
	e *p=edge[s].next;
	v[s]=1;
	while(p){
		if(!v[p->data]&&p->c>p->f)
			dfs(p->data);
		p=p->next;
	}
}

void read(){
//	ifstream cin("in.txt");
	int i,j,k,s,t,m;
	int value;
	
	
		cin>>n>>m;
		for(i=1;i<=n;i++)
		{
			cin>>value;
			e *p=new e;
			p->data=i+1;
			p->next=edge[1].next;
			edge[1].next=p;
			p->c=value;
			p->f=0;

			e *q=new e;
			q->data=1;
			q->next=edge[i+1].next;
			edge[i+1].next=q;
			q->c=q->f=0;
			p->opt=q;
			q->opt=p;
		}
		for(i=1;i<=n;i++)
		{
			cin>>value;
			e *p=new e;
			p->data=i+n+1;
			p->next=edge[n+n+2].next;
			edge[n+n+2].next=p;
			p->c=0;
			p->f=0;

			e *q=new e;
			q->data=n+n+2;
			q->next=edge[i+1+n].next;
			edge[i+1+n].next=q;
			q->f=0;q->c=value;
			p->opt=q;
			q->opt=p;
		}
		for(i=1;i<=m;i++)
		{
			cin>>t>>s;
			e *p=new e;
			p->data=t+1+n;
			p->next=edge[1+s].next;
			edge[1+s].next=p;
			p->c=10000000;
			p->f=0;

			e *q=new e;
			q->data=1+s;
			q->next=edge[t+n+1].next;
			edge[t+n+1].next=q;
			q->c=q->f=0;
			p->opt=q;
			q->opt=p;
		}
		n+=2+n;
		solve();
		printf("%d\n",flow);
		int ans=0;
		memset(v,0,sizeof(v));
		dfs(1);
		e *p=edge[1].next;
		while(p){
			if(!v[p->data])
				ans++;
			p=p->next;
		}
		p=edge[n].next;
		while(p){
			if(v[p->data])
				ans++;
			p=p->next;
		}
		cout<<ans<<endl;
		p=edge[1].next;
		while(p){
			if(!v[p->data])
				cout<<p->data-1<<" +"<<endl;
			p=p->next;
		}
		p=edge[n].next;
		while(p){
			if(v[p->data])
				cout<<p->data-n/2<<" -"<<endl;
			p=p->next;
		}

	
}

int main(){
	read();
	return 0;
}