HDU 3081 Marriage Match II（网络流+并查集+二分答案）

  1 //HDU 3081
  2 #include <queue>
  3 #include <cstdio>
  4 #include <cstring>
  5 #include <iostream>
  6 #include <algorithm>
  7 using namespace std;
  8 
  9 const int N=2333;
 10 const int M=233333;
 11 const int INF=0x3f3f3f3f;
 12 int n,m,f,s,t,cnt;
 13 int Head[N],Depth[N],cur[N],Father[N];
 14 int Next[M],V[M],W[M];
 15 bool Map[N][N];
 16 
 17 int Find(int x){return x==Father[x]?x:Father[x]=Find(Father[x]);}
 18 void Union(int x,int y){
 19     int fx=Find(x),fy=Find(y);
 20     if(fx!=fy){
 21         Father[fx]=fy;
 22     }
 23 }
 24 
 25 void init(){
 26     cnt=-1;
 27     memset(Head,-1,sizeof(Head));
 28     memset(Next,-1,sizeof(Next));
 29 }
 30 
 31 void add_edge(int u,int v,int w){
 32     cnt++;Next[cnt]=Head[u];V[cnt]=v;W[cnt]=w;Head[u]=cnt;
 33     cnt++;Next[cnt]=Head[v];V[cnt]=u;W[cnt]=0;Head[v]=cnt;
 34 }
 35 
 36 bool bfs(){
 37     queue <int> Q;
 38     while(!Q.empty()) Q.pop();
 39     memset(Depth,0,sizeof(Depth));
 40     Depth[s]=1;
 41     Q.push(s);
 42     while(!Q.empty()){
 43         int u=Q.front();Q.pop();
 44         for(int i=Head[u];i!=-1;i=Next[i]){
 45             if((W[i]>0)&&(Depth[V[i]]==0)){
 46                 Depth[V[i]]=Depth[u]+1;
 47                 Q.push(V[i]);
 48             }
 49         }
 50     }
 51     if(Depth[t]==0) return 0;
 52     return 1;
 53 }
 54 
 55 int dfs(int u,int dist){
 56     if(u==t) return dist;
 57     for(int& i=cur[u];i!=-1;i=Next[i]){
 58         if((Depth[V[i]]==Depth[u]+1)&&W[i]!=0){
 59             int di=dfs(V[i],min(dist,W[i]));
 60             if(di>0){
 61                 W[i]-=di;
 62                 W[i^1]+=di;
 63                 return di;
 64             }
 65         }
 66     }
 67     return 0;
 68 }
 69 
 70 int Dinic(){
 71     int ans=0;
 72     while(bfs()){
 73         for(int i=0;i<=2*n+1;i++) cur[i]=Head[i];
 74         while(int d=dfs(s,INF)) ans+=d;
 75     }
 76     return ans;
 77 }
 78 
 79 int check(int k){
 80     init();
 81     for(int i=1;i<=n;i++)
 82     for(int j=1+n;j<=2*n;j++)
 83     if(Map[i][j]) add_edge(i,j,1);
 84 
 85     for(int i=1;i<=n;i++) add_edge(s,i,k);
 86     for(int i=1+n;i<=2*n;i++) add_edge(i,t,k);
 87 
 88     if(Dinic()==k*n) return 1;
 89     else return 0;
 90 }
 91 
 92 int main(){
 93     int T,a,b;
 94     scanf("%d",&T);
 95     while(T--){
 96         memset(Map,0,sizeof(Map));
 97         for(int i=0;i<N;i++) Father[i]=i;
 98         scanf("%d %d %d",&n,&m,&f);
 99         for(int i=1;i<=m;i++){
100             scanf("%d %d",&a,&b);
101             Map[a][b+n]=1;
102         }
103         for(int i=1;i<=f;i++){
104             scanf("%d %d",&a,&b);
105             Union(a,b);
106         }
107         for(int i=1;i<=n;i++)
108         for(int j=i+1;j<=n;j++)
109             if(Find(i)==Find(j)){
110                 for(int k=1+n;k<=2*n;k++){
111                     Map[i][k]=Map[j][k]=(Map[i][k]||Map[j][k]);
112                 }
113             }
114         int s=0;t=2*n+1;
115         int l=0,r=111,mid;
116         while(r-l>1){
117             mid=(l+r)/2;
118             if(check(mid)) l=mid;
119             else r=mid;
120         }
121         printf("%d\n",l);
122     }
123     return 0;
124 }