[BZOJ3611][Heoi2014]大工程 虚树+dp

构建虚树不难，dp有一点技巧
把虚树上的询问点和虚点分开来讨论，初值设置的时候有一点点不同

/**************************************************************    Problem: 3611    User: di4CoveRy    Language: C++    Result: Accepted    Time:12792 ms    Memory:194580 kb****************************************************************/#include <bits/stdc++.h>#define N 1000005#define LOG 20#define INF (1<<30)using namespace std;typedef long long LL;int rd() { int r; scanf("%d",&r); return r; }struct Edge{ int a,b,next; }e[2*N],E[2*N];int G[N],T[N],D[N],fa[N],h[N],sta[N],dfn[N],Jump[N][LOG+1],siz[N],tme,n,m,tp;LL F[N],ans1;int head[N],Head[N],cnt,tot;int ans2,ans3;bool vis[N],momsen[N];inline void add(int a,int b) { e[++cnt] = (Edge){a,b,head[a]}; head[a] = cnt; }inline void add_Edge(int a,int b) { add(a,b); add(b,a); }inline void ins_Edge(int x,int y) { E[++tot] = (Edge){x,y,Head[x]}; Head[x] = tot; }inline void ins(int x,int y) {     if (x == y) return ;//  printf("::virtual : %d %d\n",x,y);    ins_Edge(x,y); ins_Edge(y,x);}void dfs(int u) {    vis[u] = 1; D[u] = D[ fa[u] ] + 1;    dfn[u] = ++tme;    for (int i=head[u];i;i=e[i].next) {        int v = e[i].b; if (vis[v]) continue;        Jump[v][0] = u;        fa[v] = u;        dfs(v);    }}int LCA(int u,int v) {    if (D[u] < D[v]) swap(u,v);    for (int i=LOG;i>=0;i--)        if (D[ Jump[u][i] ] >= D[v]) u = Jump[u][i];    if (u == v) return u;    for (int i=LOG;i>=0;i--)        if (Jump[u][i] != Jump[v][i])            u = Jump[u][i] , v = Jump[v][i];    return Jump[u][0];}void _pre() {    for (int i=1;i<=LOG;i++)        for (int _=1;_<=n;_++) Jump[_][i] = Jump[ Jump[_][i-1] ][i-1];}void dp(int u,int fr) {    siz[u] = momsen[u]?1LL:0LL;    F[u] = 0LL;    G[u] = momsen[u]?0LL:-INF;    T[u] = momsen[u]?0LL: INF;    for (int i=Head[u];i;i=E[i].next) {        int v = E[i].b; if (v == fr) continue;        dp(v,u);        ans1 += ( F[u] + siz[u] * (D[v]-D[u]) ) * siz[v] + F[v] * siz[u];        F[u] += siz[v] * (D[v]-D[u]) + F[v];         siz[u] += siz[v];        ans2 = max(G[v]+G[u]+(D[v]-D[u]) , ans2);        G[u] = max(G[u] , G[v]+D[v]-D[u]);        ans3 = min(T[v]+T[u]+(D[v]-D[u]) , ans3);        T[u] = min(T[u] , T[v]+D[v]-D[u]);    }    Head[u] = 0;}bool cmp(int p1,int p2) { return dfn[p1] < dfn[p2]; }void solve() {    int k = rd(); tot = 0;    for (int i=1;i<=k;i++) h[i] = rd();    sort(h+1,h+k+1,cmp);    for (int i=1;i<=k;i++) momsen[ h[i] ]=1;    sta[tp=1] = 1; sta[++tp] = h[1];    for (int _=2;_<=k;_++) {        for (;;) {            int u = h[_] , p = sta[tp] , q = sta[tp-1] , lca = LCA(p,u);            if (D[q] > D[lca]) ins(q,p),sta[tp--]=0;            if (D[q] == D[lca]) { ins(q,p); sta[tp--]=0; break; }            if (D[q] < D[lca]) {                ins(lca,p);                sta[tp] = lca;                 break;            }        }        sta[++tp] = h[_];    }    while (--tp) ins(sta[tp],sta[tp+1]) , sta[tp+1] = 0;    ans1 = 0 , ans2 = -INF , ans3 = INF;    dp(1,1);    printf("%lld %d %d\n",ans1,ans3,ans2);    for (int i=1;i<=k;i++) momsen[ h[i] ] = 0;    return ;}int main() {    #ifndef ONLINE_JUDGE        freopen("1.in","r",stdin);    #endif    n = rd();    for (int i=1;i<=n-1;i++) add_Edge(rd(),rd());    dfs(1);    _pre();    m = rd();    for (int i=1;i<=m;i++) solve();    return 0;}