#include <bits/stdc++.h>
using namespace std;

class HLD {
	vector<vector<int>> G;
	vector<int> vid, head, heavy, par, dep;
	int dfs(int v, int prev) {
		par[v] = prev;
		int cnt = 1, ma = 0;
		for (int to : G[v]) if (to != prev) {
			dep[to] = dep[v] + 1;
			int c = dfs(to, v);
			cnt += c;
			if (ma < c) {
				ma = c;
				heavy[v] = to;
			}
		}
		return cnt;
	}
public:
	HLD(int n) : G(n), vid(n, -1), head(n), heavy(n, -1), par(n), dep(n) {}
	void add(int u, int v) {
		G[u].push_back(v);
		G[v].push_back(u);
	}
	void build() {
		dfs(0, -1);
		int k = 0;
		queue<int> q;
		q.push(0);
		while (!q.empty()) {
			int h = q.front(); q.pop();
			for (int i = h; i != -1; i = heavy[i]) {
				vid[i] = k++;
				head[i] = h;
				for (int j : G[i]) if (j != par[i] && j != heavy[i]) q.push(j);
			}
		}
	}
	int operator[](int v) {
		return vid[v];
	}
	void for_each(int u, int v, function<void(int, int)> f) {
		while (true) {
			if (vid[u] > vid[v]) swap(u, v);
			f(max(vid[head[v]], vid[u]), vid[v]);
			if (head[u] == head[v]) break;
			v = par[head[v]];
		}
	}
};

template <typename T>
class SegmentTree {
	const int n;
	vector<vector<T>> data;
	vector<T> merge(const vector<T>& l, const vector<T>& r) {
		int nl = l.size(), nr = r.size();
		vector<T> res(nl + nr);
		for (int i = 0, j = 0, k = 0; i < nl || j < nr; k++) {
			if (j == nr)
				res[k] = l[i++];
			else if (i == nl)
				res[k] = r[j++];
			else if (l[i] <= r[j])
				res[k] = l[i++];
			else
				res[k] = r[j++];
		}
		return res;
	}
	int size(int n) {
		int res;
		for (res = 1; res < n; res <<= 1);
		return res;
	}
	T sub(int l, int r, int node, int lb, int ub, T val) {
		if (ub <= l || r <= lb) return 0;
		if (l <= lb && ub <= r) return upper_bound(data[node].begin(), data[node].end(), val) - data[node].begin();
		return sub(l, r, node * 2, lb, (lb + ub) / 2, val) + sub(l, r, node * 2 + 1, (lb + ub) / 2, ub, val);
	}
public:
	SegmentTree(const vector<T>& data_) : n(size(data_.size())), data(n * 2) {
		for (int i = 0; i < (int)data_.size(); i++)
			data[i + n].push_back(data_[i]);
		for (int i = n - 1; i >= 0; i--)
			data[i] = merge(data[i * 2], data[i * 2 + 1]);
	}
	void Update(int p, T val) {
		p += n;
		data[p][0] = val;
		while (p >>= 1) data[p] = merge(data[p * 2], data[p * 2 + 1]);
	}
	void Add(int p, T val) {
		p += n;
		data[p][0] += val;
		while (p >>= 1) data[p] = merge(data[p * 2], data[p * 2 + 1]);
	}
	T Find(int l, int r, T val) {
		return sub(l, r + 1, 1, 0, n, val);
	}
};

int main()
{
	cin.sync_with_stdio(false);
	cin.tie(0);
	int N, Q;
	cin >> N >> Q;
	vector<int> W(N), base(N);
	for (int i = 0; i < N; i++) {
		cin >> W[i];
	}
	HLD hl(N);
	for (int i = 0, u, v; i < N - 1; i++) {
		cin >> u >> v; u--; v--;
		hl.add(u, v);
	}
	hl.build();
	for (int i = 0; i < N; i++) {
		base[hl[i]] = W[i];
	}
	int v, w, l;
	SegmentTree<int> st(base);
	while (Q--) {
		cin >> v >> w >> l; v--; w--;
		int lb = 0, ub = 1000000000;
		while (lb + 1 < ub) {
			int c = lb + (ub - lb) / 2;
			int sum = 0;
			hl.for_each(v, w, [&](int ll, int rr) {
				sum += st.Find(ll, rr, c);
			});
			if (sum >= l) {
				ub = c;
			}
			else {
				lb = c;
			}
		}
		printf("%d\n", ub);
	}
	return 0;
}

Measured memory_bytes: 31872