Destroying The Graph 最小点权集--最小割--最大流

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cmath>
  5 #include <algorithm>
  6 #include <string>
  7 #include <vector>
  8 #include <set>
  9 #include <map>
 10 #include <stack>
 11 #include <queue>
 12 #include <sstream>
 13 #include <iomanip>
 14 using namespace std;
 15 typedef long long LL;
 16 const int INF = 0x4fffffff;
 17 const double EXP = 1e-5;
 18 const int MS = 2005;
 19 const int SIZE = 100005;
 20 
 21 struct edge
 22 {
 23       int v,c,f,other;
 24 }e;
 25 
 26 vector<edge> edges[MS];     //  邻接表
 27 vector<int> level_edges[MS];
 28 vector<int> ans;
 29 
 30 int que[MS],level[MS],pre[MS],hash[MS],d[MS];
 31 int s,t;
 32 
 33 void add(int u,int v,int c)
 34 {
 35       e.v=v;
 36       e.c=c;
 37       e.f=0;
 38       e.other=edges[v].size();
 39       edges[u].push_back(e);
 40 
 41       e.v=u;             //  reverse edge
 42       e.c=0;
 43       e.f=0;
 44       e.other=edges[u].size()-1;
 45       edges[v].push_back(e);
 46 }
 47 
 48 bool BFS()         // bfs 构建层次网络
 49 {
 50       int head=0,tail=0,cur,i;
 51       for(int i=s;i<=t;i++)
 52             level_edges[i].clear();
 53       memset(level,0xff,sizeof(level));
 54       que[tail++]=s;
 55       level[s]=0;
 56       while(head<tail)
 57       {
 58             cur=que[head++];
 59             for(i=0;i<edges[cur].size();i++)
 60             {
 61                   e=edges[cur][i];
 62                   if(e.c>e.f)
 63                   {
 64                         if(level[e.v]==-1)
 65                         {
 66                               que[tail++]=e.v;
 67                               level[e.v]=level[cur]+1;
 68                         }
 69                         if(level[e.v]==level[cur]+1)
 70                         {
 71                               level_edges[cur].push_back(i);
 72                         }
 73                   }
 74             }
 75       }
 76       if(level[t]!=-1)
 77             return 1;
 78       else
 79             return 0;
 80 }
 81 
 82 
 83 int dinic()
 84 {
 85       int i,j,ans=0,len;
 86       while(BFS())
 87       {
 88             memset(hash,0,sizeof(hash));
 89             while(!hash[s])
 90             {
 91                   d[s]=INF;
 92                   pre[s]=-1;
 93                   for(i=s;i!=t&&i!=-1;i=j)
 94                   {
 95                         len=level_edges[i].size();
 96                         while(len&&hash[ edges[i][level_edges[i][len-1]].v] )
 97                         {
 98                               level_edges[i].pop_back();
 99                               len--;
100                         }
101                         if(!len)
102                         {
103                               hash[i]=1;
104                               j=pre[i];
105                               continue;
106                         }
107                         j=edges[i][level_edges[i][len-1]].v;
108                         pre[j]=i;
109                         d[j]=min(d[i],edges[i][level_edges[i][len-1]].c-edges[i][level_edges[i][len-1]].f);
110                   }
111                   if(i==t)
112                   {
113                         ans+=d[t];
114                         while(i!=s)
115                         {
116                               j=pre[i];
117                               len=level_edges[j][level_edges[j].size()-1];
118                               edges[j][len].f+=d[t];
119                               if(edges[j][len].f==edges[j][len].c)
120                                     level_edges[j].pop_back();
121                               edges[i][edges[j][len].other].f-=d[t];
122                               i=j;
123                         }
124                   }
125             }
126       }
127       return ans;
128 }
129 
130 void DFS(int u)
131 {
132       int i,k;
133       hash[u]=1;
134       for(i=0;i<edges[u].size();i++)
135       {
136             k=edges[u][i].v;
137             if(!hash[k]&&edges[u][i].c-edges[u][i].f>0)
138                   DFS(k);
139       }
140 }
141 
142 int main()
143 {
144       int n,m,i,j,k,N,tmp,answer;
145       while(scanf("%d%d",&n,&m)!=EOF)
146       {
147             N=2*n+1;
148             s=0;
149             t=N;
150             for(i=s;i<=t;i++)
151                   edges[i].clear();
152             for(i=1;i<=n;i++)
153             {
154                   scanf("%d",&tmp);
155                   add(n+i,N,tmp);
156             }
157             for(i=1;i<=n;i++)
158             {
159                   scanf("%d",&tmp);
160                   add(0,i,tmp);
161             }
162             for(k=0;k<m;k++)
163             {
164                   scanf("%d%d",&i,&j);
165                   add(i,n+j,INF);
166             }
167             answer=dinic();
168             memset(hash,0,sizeof(hash));
169             DFS(0);
170             ans.clear();
171             for(i=1;i<=n;i++)
172             {
173                   if(!hash[i])
174                         ans.push_back(i);
175                   if(hash[n+i])
176                         ans.push_back(n+i);
177             }
178             printf("%d\n%d\n",answer,ans.size());
179             for(i=0;i<ans.size();i++)
180             {
181                   if(ans[i]<=n)
182                         printf("%d -\n",ans[i]);
183                   else
184                         printf("%d +\n",ans[i]-n);
185             }
186       }
187       return 0;
188 }