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| int n = edges.size() + 1;
vector neibor(n + 1, vector<pair<int, int>>());
for (auto &e : edges)
{
int i = e[0] + 1, j = e[1] + 1, w = e[2];
neibor[i].emplace_back(j, w);
neibor[j].emplace_back(i, w);
}
auto getUpLog = [](int n) -> int
{ return n ? __lg(n - 1) + 1 : 0; };
const int MX = getUpLog(n - 1);
vector fa(n + 1, vector(MX + 1, 0));
vector cost(n + 1, vector(MX + 1, 0));
vector depth(n + 1, 0);
{
auto dfs = [&](this auto &&dfs, int u, int father) -> void
{
fa[u][0] = father;
depth[u] = depth[father] + 1;
for (int k = 1; k <= MX; k++)
{
fa[u][k] = fa[fa[u][k - 1]][k - 1];
cost[u][k] = cost[fa[u][k - 1]][k - 1] + cost[u][k - 1];
}
for (auto &[v, w] : neibor[u])
{
if (v != father)
{
cost[v][0] = w;
dfs(v, u);
}
}
};
dfs(1, 0);
}
auto lca = [&](int u, int v) -> int
{
if (depth[u] > depth[v])
{
swap(u, v);
};
int dist = depth[v] - depth[u], ans = 0;
for (int k = 0; dist; k++, dist >>= 1)
{
if (dist & 1)
{
ans += cost[v][k];
v = fa[v][k];
}
}
if (u == v)
{
return ans;
}
for (int k = MX; k >= 0 && u != v; k--)
{
if (fa[u][k] != fa[v][k])
{
ans += cost[u][k] + cost[v][k];
u = fa[u][k];
v = fa[v][k];
}
}
ans += cost[u][0] + cost[v][0];
return ans;
};
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