换根DP板子题，用换根计算每个点到叶子节点的距离即可。

时间复杂度：$O(n)$

const int maxn = 2e5 + 7;
int n, k;
vector<int> edge[maxn];

int siz[maxn], sum[maxn];
void dfs(int x, int z)
{
	siz[x] = (edge[x].size() == 1);
	sum[x] = 0;
	for (int y : edge[x])
	{
		if (y == z)
			continue;
		dfs(y, x);
		siz[x] += siz[y];
		sum[x] += sum[y] + siz[y];
	}
}

int dis[maxn];
void dfs2(int x, int z)
{
	if (x != 1)
		dis[x] = dis[z] + (siz[1] - siz[x]) - siz[x];
	else
		dis[x] = sum[x];

	for (int y : edge[x])
	{
		if (y == z)
			continue;
		dfs2(y, x);
	}
}

void solve()
{
	cin >> n >> k;
	for (int i = 1; i < n; i++)
	{
		int x, y;
		cin >> x >> y;
		edge[x].push_back(y);
		edge[y].push_back(x);
	}
	dfs(1, 0);
	dfs2(1, 0);

	for (int i = 1; i <= k; i++)
	{
		int x;
		cin >> x;
		cout << dis[x] << endl;
	}
}