一般图匹配（带花树）

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int tol,head[maxn];
struct edge
{
    int u,v,next;
}es[maxm];
void addedge( int u , int v )
{
    es[tol].u = u;
    es[tol].v = v;
    es[tol].next = head[u];
    head[u] = tol++;
}
int n,m,f[maxn],match[maxn],id[maxn],pre[maxn];
int st,ed,q[maxn];
int tim,vis[maxn];
int Find( int x ){ return x==f[x]?f[x]:f[x]=Find(f[x]); }
int Lca ( int u , int v )
{
    tim++;
    while( vis[u]!=tim )
    {
        if ( u!=0 )
        {
            u = Find(u);
            if ( vis[u]==tim ) return u;
            vis[u] = tim;
            if ( match[u]!=0 ) u = Find(pre[match[u]]);
            else u = 0;
        }
        swap( u , v );
    }
    return u;
}
void change( int u , int v , int k )
{
    while ( Find(u)!=k )
    {
        pre[u] = v;
        int t = match[u];
        id[t] = 0;
        q[ed++] = t;
        if ( ed>=n-1 ) ed = 1;
        if ( Find(t)==t ) f[t] = k;
        if ( Find(u)==u ) f[u] = k;
        v = t; u = pre[v];
    }
}
void check( int X )
{
    for ( int i=1 ; i<=n ; i++ )
        f[i] = i,id[i] = -1;
    st = 1;
    ed = 2;
    q[st] = X,id[X] = 0;
    while ( st!=ed )
    {
        int u = q[st];
        for ( int i=head[u] ; i!=-1 ; i=es[i].next )
        {
            int v = es[i].v;
            if ( match[v]==0&&v!=X )
            {
                pre[v] = u;
                int last,t,now = v;
                while ( now!=0 )
                {
                    t = pre[now];
                    last = match[t];
                    match[t] = now;
                    match[now] = t;
                    now = last;
                }
                return;
            }
            if ( id[v]==-1 )
            {
                id[v] = 1;
                pre[v] = u;
                id[match[v]] = 0;
                q[ed++] = match[v];
                if ( ed>=n-1 ) ed = 1;
            }
            else if ( id[v]==0&&Find(u)!=Find(v) )
            {
                int lca = Lca( u , v );
                change( u , v , lca );
                change( v , u , lca );
            }
        }
        st++;
        if ( st>=n-1 ) st = 1;
    }
}
int solve()
{
    tim = 0; memset ( vis , 0 , sizeof(vis) );
    memset ( match , 0 , sizeof(match) );
    for ( int i=1 ; i<=n ; i++ )
        if ( match[i]==0 ) check(i);
    int res = 0;
    for ( int i=1 ; i<=n ; i++ )
        if ( match[i]!=0 ) res++;
    return res>>1;
}