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| #include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
const int N = 2.5e5, K = 2.5e5, LogN = 18;
struct edge {
int to;
long long w;
};
int dfn[N + 1], dfn_time, fa[N + 1][LogN + 1];
long long d[N + 1], min_w[N + 1][LogN + 1], a[K], f[N + 1];
bool flag[N + 1];
std::vector<edge> g[N + 1], tree[N + 1];
void dfs(int x, long long now_min, int depth) {
d[x] = depth;
dfn[x] = ++dfn_time;
for(int i = 1; (1 << i) <= d[x]; i++) {
fa[x][i] = fa[fa[x][i - 1]][i - 1];
min_w[x][i] = std::min(min_w[x][i - 1], min_w[fa[x][i - 1]][i - 1]);
}
for (auto nxt : g[x])
if (nxt.to != fa[x][0]) {
fa[nxt.to][0] = x;
min_w[nxt.to][0] = nxt.w;
dfs(nxt.to, std::min(now_min, nxt.w), depth + 1);
}
}
int get_lca(int x, int y) {
if (d[x] < d[y]) std::swap(x, y);
while (d[x] > d[y])
x = fa[x][int(log2(d[x] - d[y]))];
if (x == y) return x;
for (int i = log2(d[x]); i >= 0; --i) {
if (fa[x][i] == fa[y][i]) continue;
x = fa[x][i];
y = fa[y][i];
}
return fa[x][0];
}
int get_min(int x, int y) {
long long ans = 1LL << 50;
if (d[x] < d[y]) std::swap(x, y);
while (d[x] > d[y]) {
ans = std::min(ans, min_w[x][int(log2(d[x] - d[y]))]);
x = fa[x][int(log2(d[x] - d[y]))];
}
return ans;
}
void dp(int x) {
f[x] = 0;
for (auto nxt : tree[x]) {
dp(nxt.to);
if (flag[nxt.to]) f[x] += nxt.w;
else f[x] += std::min(f[nxt.to], nxt.w);
}
tree[x].clear();
}
int main() {
int n;
scanf("%d", &n);
for (int i = 1; i < n; i++) {
int u, v, w;
scanf("%d%d%d", &u, &v, &w);
g[u].push_back({v, w});
g[v].push_back({u, w});
}
dfs(1, 0x7fffffff, 0);
int m;
scanf("%d", &m);
while (m--) {
int k;
scanf("%d", &k);
for (int i = 1; i <= k; i++) {
scanf("%lld", &a[i]);
flag[a[i]] = true;
}
std::sort(a + 1, a + k + 1, [](int x, int y){return dfn[x] < dfn[y];});
std::vector<int> s;
s.push_back(1);
for (int i = 1; i <= k; i++) {
int lca = get_lca(a[i], s.back());
if (lca == s.back()) {
s.push_back(a[i]);
} else {
while (dfn[lca] < dfn[s.back()] && dfn[lca] < dfn[s[s.size() - 2]]) {
tree[s[s.size() - 2]].push_back({s.back(), get_min(s.back(), s[s.size() - 2])});
s.pop_back();
}
if (dfn[lca] > dfn[s[s.size() - 2]]) {
tree[lca].push_back({s.back(), get_min(lca, s.back())});
s.pop_back();
s.push_back(lca);
s.push_back(a[i]);
} else {
tree[lca].push_back({s.back(), get_min(lca, s.back())});
s.pop_back();
s.push_back(a[i]);
}
}
}
while (s.size() > 1) {
tree[s[s.size() - 2]].push_back({s.back(), get_min(s.back(), s[s.size() - 2])});
s.pop_back();
}
dp(1);
printf("%lld\n", f[1]);
for (int i = 1; i <= k; i++)
flag[a[i]] = false;
}
}
|
