带花树

Posted 2020-06-13

带花树模板

  1 #include<queue>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<algorithm>
  5 #define N 605
  6 #define M 200010
  7 using namespace std;
  8 int n,m,tot,head[N],match[N],fa[N],flower[N];
  9 bool inflower[N],vis[N];
 10 struct edge{int next,to;}e[M];
 11 queue<int>q;
 12 inline void add(int u,int v)
 13 {
 14     e[++tot]=(edge){head[u],v};
 15     head[u]=tot;
 16     e[++tot]=(edge){head[v],u};
 17     head[v]=tot;
 18 }
 19 int lca(int u,int v)
 20 {
 21     int inpath[N];
 22     memset(inpath,0,sizeof(inpath));
 23     while(1)
 24     {
 25         u=flower[u];
 26         inpath[u]=1;
 27         if(!match[u])break;
 28         u=fa[match[u]];
 29     }
 30     while(1)
 31     {
 32         v=flower[v];
 33         if(inpath[v])return v;
 34         v=fa[match[v]];
 35     }
 36 }
 37 void reset(int u,int anc)
 38 {
 39     while(u!=anc)
 40     {
 41         int v=match[u];
 42         inflower[flower[u]]=1;
 43         inflower[flower[v]]=1;
 44         v=fa[v];
 45         if(flower[v]!=anc)fa[v]=match[u];
 46         u=v;
 47     }
 48 }
 49 void bloom(int u,int v)
 50 {
 51     int t=lca(u,v);
 52     memset(inflower,0,sizeof(inflower));
 53     reset(u,t);reset(v,t);
 54     if(flower[u]!=t)fa[u]=v;
 55     if(flower[v]!=t)fa[v]=u;
 56     for(int i=1;i<=n;i++)
 57     if(inflower[flower[i]])
 58     {
 59         flower[i]=t;
 60         if(!vis[i])
 61         vis[i]=1,q.push(i);
 62     }
 63 }
 64 bool path(int s)
 65 {
 66     memset(vis,0,sizeof(vis));
 67     memset(fa,0,sizeof(fa));
 68     for(int i=1;i<=n;i++)flower[i]=i;
 69     while(!q.empty())q.pop();
 70     q.push(s);vis[s]=1;
 71     while(!q.empty())
 72     {
 73         int u=q.front();q.pop();
 74         for(int i=head[u];i;i=e[i].next)
 75         if(flower[u]!=flower[e[i].to]&&match[u]!=e[i].to)
 76         {
 77             if(e[i].to==s||(match[e[i].to]&&fa[match[e[i].to]]))
 78             bloom(u,e[i].to);
 79             else if(!fa[e[i].to])
 80             {
 81                 fa[e[i].to]=u;
 82                 if(match[e[i].to])
 83                 {
 84                     q.push(match[e[i].to]);
 85                     vis[match[e[i].to]]=1;
 86                 }
 87                 else
 88                 {
 89                     u=e[i].to;
 90                     while(u)
 91                     {
 92                         match[u]=fa[u];
 93                         swap(u,match[fa[u]]);
 94                     }
 95                     return 1;
 96                 }
 97             }
 98         }
 99     }
100     return 0;
101 }
102 void init()
103 {
104     int t,x,y;
105     scanf("%d%d%d",&n,&m,&t);
106     memset(head,0,sizeof(head));
107     memset(match,0,sizeof(match));
108     int ans=tot=0;
109     for(int i=1;i<=n;i++)
110     if(!match[i])ans+=path(i);
111 }
112 int main()
113 {
114     int T;
115     scanf("%d",&T);
116     while(T--)init();
117 }

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