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#pragma GCC optimize("O3")
#include "bits/stdc++.h"
using namespace std;
#define rep(i,a,b) for(int i=(a); i<(b); ++i)
#define all(x) x.begin(),x.end()
#define sz(x) int(x.size())
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vvi;

const int oo = 1.1e9;

mt19937 rng(69);

const int N = 4000;
int Tl[N], Tr[N], Sl[N], Sr[N];

struct segs{
    int ub; // maximum allowed here + 1
    int L[N];
    int R[N];
    int size = 0;
    void add(int l, int r){
        L[size] = l;
        R[size] = r;
        ++size;
    }
    void clear(){
        size = 0;
    }

    void unite(segs& seg, int w){
        memcpy(Tl,L,4*size);
        memcpy(Tr,R,4*size);
        Tl[size] = oo;
        memcpy(Sl,seg.L,4*seg.size);
        memcpy(Sr,seg.R,4*seg.size);
        Sl[seg.size] = oo;
        int ss = size, os = seg.size;
        clear();

        int i = 0, j = 0;
        int lastL=0, lastR=0;
        
        while(i<ss or j<os){
            int ovl = Sl[j]<oo?(Sl[j]+w-1)/w:oo;
            if (Tl[i] <= ovl){
                if (Tl[i] <= lastR){
                    lastR = max(Tr[i],lastR);
                }else{
                    if (lastR) add(lastL,lastR);
                    lastL = Tl[i];
                    lastR = Tr[i];
                }
                ++i;
            }else{
                int ovr = min((Sr[j]+w-1)/w, ub);
                if (ovl < ovr){
                    if (ovl <= lastR){
                        lastR = max(ovr,lastR);
                    }else{
                        if (lastR) add(lastL,lastR);
                        lastL = ovl;
                        lastR = ovr;
                    }
                }
                ++j;
            }
        }
        if (lastR) add(lastL,lastR);
    }
};

void solve(){
    int n,m; cin >> n >> m;

    vi cap(n);
    for(auto& c : cap){
        cin >> c;
        ++c;
    }

    //
    vector<array<int,3>> es;
    vvi adj1(n);
    rep(i,0,m){
        int x,y,w;
        cin >> x >> y >> w;
        --x, --y;
        if (w>1) {
            es.push_back({x,y,w});
        }
        else adj1[x].push_back(y);
    }

    // compress one graph

    int diam = 100;
    {
        {
            vvi d(n,vi(n,1e9));
            rep(i,0,n) d[i][i] = 0;
            rep(i,0,n) for(auto j : adj1[i])
                d[i][j] = 1;

            rep(k,0,n) rep(i,0,n) rep(j,0,n){
                d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
            }
            diam = 0;
            rep(i,0,n) rep(j,0,n) if (d[i][j] < 1000000){
                diam = max(diam, d[i][j]);
            }
        }

        while(diam>4){    
            vi ord(n);
            iota(all(ord),0);
            shuffle(all(ord),rng);

            for(auto st : ord){
                vi d(n,-1);
                vvi par(__lg(n)+1, vi(n));
                par[0][st] = st;
                d[st] = 0;
                queue<array<int,2>> q;
                q.push({st,0});
                while(sz(q)){
                    auto [at,dist] = q.front();
                    q.pop();

                    d[at] = dist;
                    for(auto to : adj1[at]) if (d[to]<0){
                        q.push({to,dist+1});
                        d[to] = dist+1;
                        par[0][to] = at;
                    }
                }

                rep(i,0,__lg(n)) rep(j,0,n) 
                    par[i+1][j] = par[i][par[i][j]];

                // add powers
                rep(i,0,n) if (d[i]>1){
                    for(int w = 2, j = 1; w<=d[i]; ++j, w*=2){
                        adj1[par[j][i]].push_back(i);
                    }
                }
            }

            vvi d(n,vi(n,1e9));
            rep(i,0,n) d[i][i] = 0;
            rep(i,0,n) for(auto j : adj1[i])
                d[i][j] = 1;

            rep(k,0,n) rep(i,0,n) rep(j,0,n){
                d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
            }
            diam = 0;
            rep(i,0,n) rep(j,0,n) if (d[i][j] < 1000000){
                diam = max(diam, d[i][j]);
            }
        }

        rep(i,0,n){
            sort(all(adj1[i]));
            adj1[i].erase(unique(all(adj1[i])),end(adj1[i]));
            for(auto j : adj1[i]){
                es.push_back({i,j,1});
            }
        }
    }

    // cout << "SIZE EDGES: " << sz(es) << '\n';
    // cout << "DIAMETER: " << diam << '\n';
    // cout << endl;
    // 

    int lo = 0, hi = cap[n-1]-1;
    while(lo<hi){
        int mid = (lo+hi+1)/2;
        
        vector<segs> a(n);
        rep(i,0,n) a[i].ub = cap[i];

        a[n-1].add(mid, cap[n-1]);

        rep(i,0,30*(diam+1)){
            shuffle(all(es),rng);

            for(auto [x,y,w] : es){
                a[x].unite(a[y], w);
            }
            if (a[0].size and *a[0].L == 1) break;
        }

        if (a[0].size and *a[0].L == 1){
            lo = mid;
        }else{
            hi = mid-1;
        }
    }

    if (lo==0) cout << "-1\n";
    else cout << lo << '\n';
}

int main(){
    cin.tie(NULL),cin.sync_with_stdio(false);
    
    int t; cin >> t;
    while(t--) solve();
}