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| #include <cstdio>
#include <vector>
#include <algorithm>
#define pb push_back
using namespace std;
template <class Type>
void read (Type &x)
{
char c;
bool flag = false;
while ((c = getchar()) < '0' || c > '9')
flag |= c == '-';
x = c - '0';
while ((c = getchar()) >= '0' && c <= '9')
x = (x << 3) + (x << 1) + c - '0';
if (flag) x = ~x + 1;
}
template <class Type, class ...Rest>
void read (Type &x, Rest &...y) { read(x); read(y...); }
template <class Type>
void write (Type x)
{
if (x < 0) putchar('-'), x = ~x + 1;
if (x > 9) write(x / 10);
putchar('0' + x % 10);
}
typedef long long LL;
const int N = 25e4 + 10, M = 20, inf = 1e5;
bool key[N];
int top, stk[N];
LL f[N];
int n, m, q, d[N], h[N];
int stmp, dfn[N], lg[N], p[N][M], w[N][M];
struct Edge { int v, w; };
vector <Edge> e[N], g[N];
void dfs (int u = 1, int fa = 0)
{
dfn[u] = ++stmp;
d[u] = d[fa] + 1;
p[u][0] = fa;
for (int i = 1; 1 << i < d[u]; ++i)
{
p[u][i] = p[p[u][i - 1]][i - 1];
w[u][i] = min(w[u][i - 1], w[p[u][i - 1]][i - 1]);
}
for (Edge i : e[u]) if (i.v ^ fa)
{
w[i.v][0] = i.w;
dfs(i.v, u);
}
}
int lca (int a, int b)
{
if (d[a] < d[b]) swap(a, b);
for (int i = lg[d[a] - d[b]]; ~i; i = lg[d[a] - d[b]])
a = p[a][i];
if (a == b) return a;
for (int i = lg[d[a] - 1]; ~i; --i)
if (p[a][i] ^ p[b][i])
a = p[a][i], b = p[b][i];
return p[a][0];
}
int calc (int a, int b)
{
int res = inf;
if (d[a] < d[b]) swap(a, b);
for (int i = lg[d[a] - d[b]]; ~i; i = lg[d[a] - d[b]])
res = min(res, w[a][i]), a = p[a][i];
if (a == b) return res;
for (int i = lg[d[a] - 1]; ~i; --i)
if (p[a][i] ^ p[b][i])
{
res = min(res, min(w[a][i], w[b][i]));
a = p[a][i], b = p[b][i];
}
return p[a][0];
}
LL dp (int u = 1)
{
f[u] = 0;
for (Edge i : g[u])
f[u] += key[i.v] ? i.w : min(dp(i.v), (LL)i.w);
return f[u];
}
int main ()
{
read(n);
for (int i = 1, a, b, c; i < n; ++i)
{
read(a, b, c);
e[a].pb((Edge){b, c}), e[b].pb((Edge){a, c});
}
lg[0] = -1;
for (int i = 2; i <= n; ++i)
lg[i] = lg[i >> 1] + 1;
dfs();
read(q);
auto add = [&](int u, int v) { g[u].pb((Edge){v, calc(u, v)}); };
while (q--)
{
read(m);
for (int i = 1; i <= m; ++i)
read(h[i]), key[h[i]] = true;
sort(h + 1, h + m + 1, [&](int a, int b){ return dfn[a] < dfn[b]; });
g[stk[top = 1] = 1].clear();
for (int i = 1; i <= m; ++i) if (h[i] ^ 1)
{
int t = lca(h[i], stk[top]);
if (t ^ stk[top])
{
for (; dfn[t] < dfn[stk[top - 1]]; --top)
add(stk[top - 1], stk[top]);
if (dfn[t] > dfn[stk[top - 1]])
{
g[t].clear();
add(t, stk[top]);
stk[top] = t;
}
else add(stk[top - 1], stk[top]), --top;
}
g[stk[++top] = h[i]].clear();
}
for (; top > 1; --top)
add(stk[top - 1], stk[top]);
write(dp()), puts("");
for (int i = 1; i <= m; ++i)
key[h[i]] = false;
}
return 0;
}
|