HDU 4292 Food(最大流)

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstdlib>
 5 #include <cstring>
 6 #include <string>
 7 #include <queue>
 8 #include <ctime>
 9 #include <cmath>
10 #include <map>
11 #define inf 0x7fffffff
12 int tot,go[1200005],first[200005],next[1200005];
13 int flow[1200005],op[1200005],dis[200005],cnt[200005];
14 int n,m1,m2,S,T,nodes;
15 int read(){
16     char ch=getchar();int t=0,f=1;
17     while (ch<‘0‘||ch>‘9‘){if (ch==‘-‘) f=-1;ch=getchar();}
18     while (‘0‘<=ch&&ch<=‘9‘){t=t*10+ch-‘0‘;ch=getchar();}
19     return t*f;
20 }
21 void insert(int x,int y,int z){
22     tot++;
23     go[tot]=y;
24     next[tot]=first[x];
25     first[x]=tot;
26     flow[tot]=z;
27 }
28 void add(int x,int y,int z){
29     insert(x,y,z);op[tot]=tot+1;
30     insert(y,x,0);op[tot]=tot-1;
31 }
32 int dfs(int x,int f){
33     if (x==T) return f;
34     int mn=nodes+1,sum=0;
35     for (int i=first[x];i;i=next[i]){
36         int pur=go[i];
37         if (dis[pur]+1==dis[x]&&flow[i]){
38             int save=dfs(pur,std::min(f-sum,flow[i]));
39             flow[i]-=save;
40             flow[op[i]]+=save;
41             sum+=save;
42             if (sum==f||dis[S]>=nodes) return sum;
43         }
44         if (flow[i]) mn=std::min(mn,dis[pur]);
45     }
46     if (sum==0){
47         cnt[dis[x]]--;
48         if (cnt[dis[x]]==0){
49             dis[S]=nodes;
50         }else{
51             dis[x]=mn+1;
52             cnt[dis[x]]++;
53         }
54     }
55     return sum;
56 }
57 int main(){
58    while (scanf("%d",&n)!=EOF){
59     m1=read();m2=read();
60     tot=0;memset(first,0,sizeof first);
61     memset(dis,0,sizeof dis);
62     memset(cnt,0,sizeof cnt);
63     S=0;T=n+m1+m2+1+n;nodes=T+1;
64     for (int i=1;i<=m1;i++){
65         int x=read();
66         add(S,i+2*n,x);
67     }
68     for (int i=1;i<=m2;i++){
69         int x=read();
70         add(n*2+m1+i,T,x);
71     }
72     char s[200005];
73     for (int i=1;i<=n;i++){
74         scanf("%s",s+1);
75         for (int j=1;j<=m1;j++)
76          if (s[j]==‘Y‘) add(j+2*n,i,1);
77     }
78     for (int i=1;i<=n;i++)
79      add(i,i+n,1);
80     for (int i=1;i<=n;i++){
81         scanf("%s",s+1);
82         for (int j=1;j<=m2;j++)
83          if (s[j]==‘Y‘) add(i+n,j+2*n+m1,1);
84     } 
85     int ans=0;
86     while (dis[S]<nodes) ans+=dfs(S,inf);
87     printf("%d\n",ans);
88    }
89 }