[BZOJ2286][Sdoi2011消耗战] 虚树

看别人的博客建虚树看了半天没看懂，按照自己的思路写，最后才发现是博主把一个深度depth写成了dfn
诶虚树入门，虚树建出来以后dp一下就出来了
虚树的构造主要思想就是维护右链
注意long long

#include <bits/stdc++.h>#define N 2000050#define LOG 25#define INF (1LL<<62)using namespace std;typedef long long LL;int rd() {    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x*f;}LL cut[N];int h[N],dfn[N],Jump[N][LOG+1],D[N],fa[N],tmp[N],cnt,tme;int sta[N],tp,k,tot,n,m;struct Edge{ int a,b,v,next; }e[2*N];inline void add(int a,int b,int v) {     e[++cnt] = (Edge){a,b,v,h[a]};h[a] = cnt;}inline void add_Edge(int a,int b,int v) { add(a,b,v); add(b,a,v); }vector<int> E[N];inline void ins(int a,int b) {     if (a == b) return ;//  printf("::debug %d %d\n",a,b);    E[a].push_back(b) , E[b].push_back(a); }void dfs(int u) {    dfn[u] = ++tme; D[u] = D[ fa[u] ] + 1;    for (int i=h[u];i;i=e[i].next) {        int v = e[i].b , cp = e[i].v;        if (dfn[v]) continue;        cut[v] = min(cut[u] , 1LL*cp);        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];}bool cmp(int p1,int p2) { return dfn[p1] < dfn[p2]; }LL dp(int u,int fr) {    LL ret = 0LL;    for (int i=0;i<(int)E[u].size();i++) {        int v = E[u][i]; if (v == fr) continue;        ret += dp(v,u);    }    if (!ret) ret = cut[u];    E[u].clear();    return min(1LL*cut[u] , ret);}inline void solve() {    #ifndef ONLINE_JUDGE        memset(sta,0,sizeof(sta));        memset(tmp,0,sizeof(tmp));    #endif    cnt = 0 , k = rd() , tot = 1;    for (int i=1;i<=k;i++) tmp[i] = rd();    sort(tmp+1,tmp+k+1,cmp);    for (int i=2;i<=k;i++)         if (LCA(tmp[tot],tmp[i]) != tmp[tot]) tmp[++tot] = tmp[i];    sta[++tp] = 1;    sta[++tp] = tmp[1];    for (int i=2;i<=tot;i++) {        for (;;) {            int now = tmp[i] , p = sta[tp] , q = sta[tp-1] , lca = LCA(now,p);            if (D[q] > D[lca]) ins(q,p) , tp--;            if (D[q] == D[lca]) {                 ins(lca,p);                 sta[tp--] = 0;                break;            }            if (D[q] < D[lca]) {                ins(lca,p);                sta[tp] = lca;                  break;            }        }        sta[++tp] = tmp[i];    }    while (--tp) ins(sta[tp],sta[tp+1]);    LL ans = dp(1,0);    printf("%I64d\n",ans);    return ;}void _pre() {    for (int i=1;i<=LOG;i++)        for (int _=1;_<=n;_++) Jump[_][i] = Jump[ Jump[_][i-1] ][i-1];}int main() {    #ifndef ONLINE_JUDGE        freopen("1.in","r",stdin);    #endif    n = rd();    for (int _=1;_<=n-1;_++) { int a=rd(),b=rd(),v=rd(); add_Edge(a,b,v); }    cut[1] = INF; Jump[1][0] = 1;    dfs(1);    _pre();    m = rd();    for (int _=1;_<=m;_++) solve();    return 0;}