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#include <iostream>
#include <vector>
#include <queue>
#include <set>
#include <tuple>
#include <algorithm>
#include <limits>

using namespace std;

struct Amplifier {
    int from, to;
    long long w;
};

struct State {
    int node;
    long long L, R;
};

vector<vector<Amplifier>> forwardGraph;
vector<vector<Amplifier>> revGraph;
vector<long long> capacity;
vector< set<long long> > reached;
int n;

long long LIMIT = 10000;

long long ceilDiv(long long a, long long b) {
    return (a + b - 1) / b;
}

bool isContained(const set<pair<long long, long long>> &intervals, long long L, long long R) {
    auto it = intervals.upper_bound({L, numeric_limits<long long>::max()});
    if (it != intervals.begin()) {
        --it;
        if (it->first <= L && it->second >= R)
            return true;
    }
    return false;
}

pair<long long, long long> mergeInterval(set<pair<long long, long long>> &intervals, long long L, long long R) {
    auto it = intervals.lower_bound({L, -1});
    if (it != intervals.begin()) {
        auto prev = it;
        prev--;
        if (prev->second >= L) {
            L = min(L, prev->first);
            R = max(R, prev->second);
            intervals.erase(prev);
        }
    }
    while (it != intervals.end() && it->first <= R) {
        L = min(L, it->first);
        R = max(R, it->second);
        auto tmp = it;
        it++;
        intervals.erase(tmp);
    }
    intervals.insert({L, R});
    return {L, R};
}

bool check(long long low, long long high) {
    if (low > high) return false;

    queue<State> q;
    q.push({n - 1, low, high});

    vector< set<pair<long long, long long>> > visited(n);
    visited[n - 1].insert({low, high});

    while (!q.empty()) {
        State cur = q.front();
        q.pop();

        auto lower = reached[cur.node].lower_bound(cur.L);
        if (lower != reached[cur.node].end() && *lower <= cur.R) {
            return true;
        }

        for (auto &amp : revGraph[cur.node]) {
            long long newLow = max((long long)1, ceilDiv(cur.L, amp.w));
            long long newHigh = min(capacity[amp.from], cur.R / amp.w);
            if (newLow > newHigh)
                continue;
            if (isContained(visited[amp.from], newLow, newHigh))
                continue;
            pair<long long, long long> merged = mergeInterval(visited[amp.from], newLow, newHigh);
            q.push({amp.from, merged.first, merged.second});
        }
    }
    return false;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
    cin >> T;
    while (T--) {
        int m;
        cin >> n >> m;

        capacity.resize(n);
        for (int i = 0; i < n; i++) {
            cin >> capacity[i];
        }

        forwardGraph.assign(n, vector<Amplifier>());
        revGraph.assign(n, vector<Amplifier>());
        for (int i = 0; i < m; i++) {
            int a, b;
            long long w;
            cin >> a >> b >> w;
            forwardGraph[a - 1].push_back({a - 1, b - 1, w});
            revGraph[b - 1].push_back({a - 1, b - 1, w});
        }

        reached.assign(n, set<long long>());
        queue<pair<int, long long>> bfsQueue;

        reached[0].insert(1);
        bfsQueue.push({0, 1});

        while (!bfsQueue.empty()) {
            auto [router, power] = bfsQueue.front();
            bfsQueue.pop();

            for (auto &amp : forwardGraph[router]) {
                int nextRouter = amp.to;
                long long newPower = power * amp.w;
                if (newPower > capacity[nextRouter]) {
                    continue;
                }
                if (reached[nextRouter].find(newPower) == reached[nextRouter].end() && newPower < LIMIT) {
                    reached[nextRouter].insert(newPower);
                    bfsQueue.push({nextRouter, newPower});
                }
            }
        }

        long long low = 1, high = capacity[n - 1], result = -1;
        if (!check(low, high)) {
            cout << -1 << endl;
            continue;
        }
        while (low <= high) {
            long long mid = (low + high) / 2;
            if (check(mid, high)) {
                result = mid;
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        cout << result << endl;
    }
    return 0;
}