<虚树+树型DP> SDOI2011消耗战

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>using namespace std;typedef long long LL;
const int MAXN = 25e4 + 10;inline LL in()
{LL x = 0, flag = 1; char ch = getchar();while (ch < '0' || ch > '9') { if (ch == '-') flag = 1; ch = getchar(); }while (ch >= '0' && ch <= '9') x = (x << 3) + (x << 1) + (ch ^ 48), ch = getchar();return x * flag;
}int n, m;struct Gra
{int head[MAXN], nume;struct Adj { int nex, to; LL w; } adj[MAXN << 1] ;void clear(){memset(head, 0, sizeof head);nume = 0;}void addedge(int from, int to, LL w){adj[++ nume] = (Adj) { head[from], to, w } ;head[from] = nume ;}void link(int from, int to, LL w){addedge(from, to, w);addedge(to, from, w);}
} g[2];
int dep[MAXN], up[21][MAXN], lg[MAXN], dfn[MAXN], ind;
LL mn[MAXN];
void DFS(int u, int fa)
{dfn[u] = ++ ind;dep[u] = dep[fa] + 1;up[0][u] = fa;for (int i = 1; (1 << i) <= dep[u]; ++ i)up[i][u] = up[i - 1][up[i - 1][u]];for (int i = g[0].head[u]; i; i = g[0].adj[i].nex){int v = g[0].adj[i].to;if (v == fa) continue;mn[v] = min(mn[u], g[0].adj[i].w);DFS(v, u);}
}
int lca(int x, int y)
{if (dep[x] > dep[y]) swap(x, y);while (dep[x] != dep[y]) y = up[lg[dep[y] - dep[x]]][y];if (x == y) return x;for (int i = lg[dep[x]]; i >= 0; -- i)if (up[i][x] != up[i][y]) x = up[i][x], y = up[i][y];return up[0][x];
}int key[MAXN], stk[MAXN], top;
bool iskey[MAXN];
void insert(int u)
{if (top == 1) return  (void) (stk[++ top] = u);int LCA = lca(u, stk[top]);if (LCA == stk[top]) return (void) (stk[++ top] = u);while (top > 1 && dep[LCA] <= dep[stk[top - 1]]){g[1].addedge(stk[top - 1], stk[top], 0);-- top;}if (LCA != stk[top]) g[1].addedge(LCA, stk[top], 0), stk[top] = LCA;stk[++ top] = u;
}
LL search(int u)
{LL ret = 0;for (int i = g[1].head[u]; i; i = g[1].adj[i].nex){int v = g[1].adj[i].to;ret += search(v);}if (iskey[u] || ret > mn[u] * 1LL) ret = mn[u];iskey[u] = false; g[1].head[u] = 0;return ret;
}bool cmp(int x, int y) { return dfn[x] < dfn[y]; }int main()
{n = in();for (int i = 1; i <= n; ++ i) lg[i] = lg[i - 1] + ((2 << lg[i - 1]) == i);for (int i = 1; i < n; ++ i){int u = in(), v = in(); LL w = in();g[0].link(u, v, w);}mn[1] = 1e18;DFS(1, 0);m = in();while (m --){int q = in();for (int i = 1; i <= q; ++ i) key[i] = in(), iskey[key[i]] = true ;sort(key + 1, key + q + 1, cmp);top = 0;stk[++ top] = 1;for (int i = 1; i <= q; ++ i) insert(key[i]);while (top > 1) g[1].addedge(stk[top - 1], stk[top], 0), -- top;g[1].nume = 0;printf("%lld\n", search(1));}return 0;
}