b2OJ_1565_[NOI2009]植物大战僵尸_拓扑排序+最大权闭合子图

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <algorithm>
  4 #include <queue>
  5 using namespace std;
  6 #define S (n*m+1)
  7 #define T (n*m+2)
  8 #define P(x,y) (m*(x-1)+y) 
  9 #define inf 100000000
 10 int head[700],to[1000010],nxt[1000010],flow[1000010],c[1000010],cnt=1,dep[700];
 11 int n,m,can[700],sum,val[700];
 12 void add(int u,int v,int f)
 13 {
 14     to[++cnt]=v;nxt[cnt]=head[u];head[u]=cnt;flow[cnt]=f;
 15     to[++cnt]=u;nxt[cnt]=head[v];head[v]=cnt;flow[cnt]=0;
 16 }
 17 bool bfs()
 18 {
 19     queue <int> q;
 20     memset(dep,0,sizeof(dep));
 21     q.push(S);dep[S]=1;
 22     while(q.size())
 23     {
 24         int x=q.front();q.pop();
 25         for(int i=head[x];i;i=nxt[i])
 26         {
 27             if(!dep[to[i]]&&flow[i]&&can[to[i]])
 28             {
 29                 dep[to[i]]=dep[x]+1;
 30                 q.push(to[i]);
 31             }
 32         }
 33     }
 34     return dep[T];
 35 }
 36 int dfs(int x,int mf)
 37 {
 38     if(x==T)return mf;
 39     int nf=0;
 40     for(int i=head[x];i;i=nxt[i])
 41     {
 42         if(dep[to[i]]==dep[x]+1&&flow[i]&&can[to[i]])
 43         {
 44             int tmp=dfs(to[i],min(flow[i],mf-nf));
 45             nf+=tmp;
 46             flow[i]-=tmp;
 47             flow[i^1]+=tmp; 
 48             if(nf==mf)break;
 49         }
 50     }
 51     dep[x]=0;
 52     return nf;
 53 }
 54 void dinic()
 55 {
 56     int ans=0,f;
 57     while(bfs())
 58     {
 59         while(f=dfs(S,inf))
 60         {
 61             ans+=f; 
 62         }
 63     }
 64     printf("%d",sum-ans);
 65 }
 66 void topsort()
 67 {
 68     queue <int> q;
 69     for(int i=1;i<=T;i++)
 70     {
 71         if(!c[i])q.push(i); 
 72     }
 73     while(q.size())
 74     {
 75         int x=q.front();q.pop();
 76         can[x]=1;
 77         if(val[x]>0)sum+=val[x];
 78         for(int i=head[x];i;i=nxt[i])
 79         {
 80             c[to[i]]--;
 81             if(c[to[i]]==0)q.push(to[i]);
 82         }
 83     }
 84 }
 85 int main()
 86 {
 87     scanf("%d%d",&n,&m);
 88     int x,y,z,w;
 89     for(int i=1;i<=n*m;i++)
 90     {
 91         scanf("%d%d",&x,&y);
 92         val[i]=x;
 93         if(x>0)add(S,i,x),c[S]++;
 94         else add(i,T,-x),c[i]++;
 95         if(i%m)add(i,i+1,inf),c[i]++;
 96         while(y--)
 97         {
 98             scanf("%d%d",&z,&w);
 99             add(P(z+1,w+1),i,inf);  
100             c[P(z+1,w+1)]++;
101         }
102     }
103     topsort();
104     dinic();
105 }
106   
107 /***************************************************************
108     Problem: 1580
109     User: 20170105
110     Language: C++
111     Result: Accepted
112     Time:320 ms
113     Memory:16704 kb
114 ****************************************************************/