zoj 2429 Destroying The Graph 最小点权覆盖

#include <cstdio>
#include <string.h>
#include <vector>
using namespace std;
#define Max 230
#define INF 100000000
int flow[Max][Max],d[Max];
int vis[Max*3];
int sta,end;
vector <int> sum;
int min(int a,int b)
{
if(a<b) return a;
else return b;
}
void dfs(int u)
{
int i,k;
vis[u]=1;
for(i=0;i<=end;i++)
{
if(!vis[i]&&flow[u][i])
dfs(i);
}
}
bool bfs(int s)
{
int front=0,rear=0;
int q[Max*100];
int k,i;
memset(d,-1,sizeof(d));
q[rear++]=s;  d[s]=0;
while(front<rear)
{
k=q[front++];
for(i=1;i<=end;i++)
if(flow[k][i]>0&&d[i]==-1)
{
d[i]=d[k]+1;
q[rear++]=i;
}
}
if(d[end]>=0)   return true;
return false;
}

int dinic(int k,int sum)
{
int i,a;
if(k==end)    return sum;
int os=sum;
for(i=1;i<=end&∑i++)
if(d[i]==d[k]+1&&flow[k][i]>0)
{
a=dinic(i,min(sum,flow[k][i]));
flow[k][i]-=a;
flow[i][k]+=a;
sum-=a;
}
return os-sum;
}
int main()
{
int w1[120],w2[120];
int n,m;
int i,t;
scanf("%d",&t);
while(t--)
{
int x,y;
int ans=0;
memset(flow,0,sizeof(flow));
scanf("%d%d",&n,&m);
sta=0;end=2*n+1;
for(i=1;i<=n;i++)
scanf("%d",&w1[i]);
for(i=1;i<=n;i++)
scanf("%d",&w2[i]);
for(i=1;i<=n;i++) flow[i+n][end]=w1[i];
for(i=1;i<=n;i++) flow[sta][i]=w2[i];
for(i=1;i<=m;i++)
{
scanf("%d%d",&x,&y);
flow[x][y+n]=INF;
}
while(bfs(sta))
ans+=dinic(sta,INF);
printf("%d\n",ans);
memset(vis,0,sizeof(vis));
dfs(0);
sum.clear();
for(i=1;i<=n;i++)
{
if(!vis[i]) sum.push_back(i);
if(vis[i+n]) sum.push_back(i+n);
}
printf("%d\n",sum.size());
for(i=0;i<sum.size();i++)
{
if(sum[i]<=n) printf("%d-\n",sum[i]);
else printf("%d+\n",sum[i]-n);
}
printf("\n");
}
return 0;
}