Jamie's Contact Groups

  1 #include<iostream>
  2 #include<cstring>
  3 #include<algorithm>
  4 #include<cstdio>
  5 #include<queue>
  6 #define INF 100000000
  7 using namespace std;
  8 const int N=3205;
  9 const int M=1000000;
 10 struct Node{
 11    int v;
 12    int f;
 13    int next;
 14 }edge[M];
 15 int n,m,u,v,cnt,sx,ex;
 16 int head[N],pre[N];
 17 int val[N][40];//根据题目要求申请
 18 void init(){
 19     cnt=0;
 20     memset(head,-1,sizeof(head));
 21 }
 22 void add(int u,int v,int w){
 23     edge[cnt].v=v;
 24     edge[cnt].f=w;
 25     edge[cnt].next=head[u];
 26     head[u]=cnt++;
 27     edge[cnt].f=0;
 28     edge[cnt].v=u;
 29     edge[cnt].next=head[v];
 30     head[v]=cnt++;
 31 }
 32 bool BFS(){
 33   memset(pre,0,sizeof(pre));
 34   pre[sx]=1;
 35   queue<int>Q;
 36   Q.push(sx);
 37  while(!Q.empty()){
 38      int d=Q.front();
 39      Q.pop();
 40      for(int i=head[d];i!=-1;i=edge[i].next    ){
 41         if(edge[i].f&&!pre[edge[i].v]){
 42             pre[edge[i].v]=pre[d]+1;
 43             Q.push(edge[i].v);
 44         }
 45      }
 46   }
 47  return pre[ex]>0;
 48 }
 49 int dinic(int flow,int ps){
 50     int f=flow;
 51      if(ps==ex)return f;
 52      for(int i=head[ps];i!=-1;i=edge[i].next){
 53         if(edge[i].f&&pre[edge[i].v]==pre[ps]+1){
 54             int a=edge[i].f;
 55             int t=dinic(min(a,flow),edge[i].v);
 56               edge[i].f-=t;
 57               edge[i^1].f+=t;
 58             flow-=t;
 59              if(flow<=0)break;
 60         }
 61 
 62      }
 63       if(f-flow<=0)pre[ps]=-1;
 64       return f-flow;
 65 }
 66 int solve(){
 67     int sum=0;
 68     while(BFS())
 69         sum+=dinic(INF,sx);
 70     return sum;
 71 }
 72 char str[20];
 73 int ans[N][N];
 74 int tot[N],top;
 75 void build(int mid){
 76      init();
 77      for(int i=1;i<=n;i++){
 78         for(int j=1;j<=tot[i];j++){
 79             add(i+n,ans[i][j]+2*n,1);
 80         }
 81         add(i,i+n,1);
 82         add(0,i,1);
 83      }
 84      for(int i=1;i<=m;i++){
 85         add(i+2*n,i+2*n+m,mid);
 86         add(i+2*n+m,2*m+2*n+1,INF);
 87      }
 88 }
 89 int as,temp;
 90 int main() {
 91     while(~scanf("%d%d",&n,&m)&&n) {
 92          init();
 93          as=0;
 94        for(int i=1;i<=n;i++){
 95           scanf("%s",str);
 96           top=0;
 97           while(getchar()!=‘\n‘){
 98               scanf("%d",&temp);
 99               //printf("**%d\n",temp);
100               ans[i][++top]=++temp;
101           }
102             tot[i]=top;
103        }
104        int l=0,r=n;
105        sx=0,ex=2*n+2*m+1;
106        while(l<=r){
107           int mid=(l+r)/2;
108           build(mid);
109           if(solve()==n){
110             r=mid-1;
111             as=mid;
112           }
113           else
114             l=mid+1;
115        }
116     printf("%d\n",as);
117 
118     }
119     return 0;
120 }