#include<bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1000003;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename Monoid, typename OperatorMonoid, typename F, typename G, typename H, typename S >
struct LinkCutTree {
  //using F = function< Monoid(Monoid, Monoid) >;
  //using G = function< Monoid(Monoid, OperatorMonoid, int) >;
  //using H = function< OperatorMonoid(OperatorMonoid, OperatorMonoid) >;
  //using S = function< Monoid(Monoid) >;

  struct Node {
    Node *l, *r, *p;
    int idx;
    Monoid key, sum;
    OperatorMonoid lazy;

    bool rev;
    int sz;

    bool is_root() {
      return !p || (p->l != this && p->r != this);
    }

    Node(int idx, const Monoid &key, const OperatorMonoid &om) :
        idx(idx), key(key), sum(key), lazy(om), sz(1),
        l(nullptr), r(nullptr), p(nullptr), rev(false) {}
  };

  const Monoid M1;
  const OperatorMonoid OM0;
  const F f;
  const G g;
  const H h;
  const S s;

  LinkCutTree() : LinkCutTree([](Monoid a, Monoid b) { return a + b; }, [](Monoid a) { return a; }, Monoid()) {}

  LinkCutTree(const F &f, const S &s, const Monoid &M1) :
      LinkCutTree(f, G(), H(), s, M1, OperatorMonoid()) {}

  LinkCutTree(const F &f, const G &g, const H &h, const S &s,
              const Monoid &M1, const OperatorMonoid &OM0) :
      f(f), g(g), h(h), s(s), M1(M1), OM0(OM0) {}

  Node *make_node(int idx, const Monoid &v = Monoid()) {
    return new Node(idx, v, OM0);
  }

  void propagate(Node *t, const OperatorMonoid &x) {
    t->lazy = h(t->lazy, x);
    t->key = g(t->key, x, 1);
    t->sum = g(t->sum, x, t->sz);
  }

  void toggle(Node *t) {
    assert(t);
    swap(t->l, t->r);
    t->sum = s(t->sum);
    t->rev ^= true;
  }

  void push(Node *t) {
    if(t->lazy != OM0) {
      if(t->l) propagate(t->l, t->lazy);
      if(t->r) propagate(t->r, t->lazy);
      t->lazy = OM0;
    }
    if(t->rev) {
      if(t->l) toggle(t->l);
      if(t->r) toggle(t->r);
      t->rev = false;
    }
  }

  void update(Node *t) {
    t->sz = 1;
    t->sum = t->key;
    if(t->l) t->sz += t->l->sz, t->sum = f(t->l->sum, t->sum);
    if(t->r) t->sz += t->r->sz, t->sum = f(t->sum, t->r->sum);
  }

  void rotr(Node *t) {
    auto *x = t->p, *y = x->p;
    if((x->l = t->r)) t->r->p = x;
    t->r = x, x->p = t;
    update(x), update(t);
    if((t->p = y)) {
      if(y->l == x) y->l = t;
      if(y->r == x) y->r = t;
      update(y);
    }
  }

  void rotl(Node *t) {
    auto *x = t->p, *y = x->p;
    if((x->r = t->l)) t->l->p = x;
    t->l = x, x->p = t;
    update(x), update(t);
    if((t->p = y)) {
      if(y->l == x) y->l = t;
      if(y->r == x) y->r = t;
      update(y);
    }
  }

  void splay(Node *t) {
    push(t);
    while(!t->is_root()) {
      auto *q = t->p;
      if(q->is_root()) {
        push(q), push(t);
        if(q->l == t) rotr(t);
        else rotl(t);
      } else {
        auto *r = q->p;
        push(r), push(q), push(t);
        if(r->l == q) {
          if(q->l == t) rotr(q), rotr(t);
          else rotl(t), rotr(t);
        } else {
          if(q->r == t) rotl(q), rotl(t);
          else rotr(t), rotl(t);
        }
      }
    }
  }

  Node *expose(Node *t) {
    Node *rp = nullptr;
    for(Node *cur = t; cur; cur = cur->p) {
      splay(cur);
      cur->r = rp;
      update(cur);
      rp = cur;
    }
    splay(t);
    return rp;
  }

  void link(Node *child, Node *parent) {
    expose(child);
    expose(parent);
    child->p = parent;
    parent->r = child;
  }

  void cut(Node *child) {
    expose(child);
    auto *parent = child->l;
    child->l = nullptr;
    parent->p = nullptr;
  }

  void evert(Node *t) {
    expose(t);
    toggle(t);
    push(t);
  }

  Node *lca(Node *u, Node *v) {
    expose(u);
    return expose(v);
  }

  vector< int > getpath(Node *x) {
    vector< int > vs;
    function< void(Node *) > dfs = [&](Node *cur) {
      if(!cur) return;
      push(cur);
      dfs(cur->r);
      vs.push_back(cur->idx);
      dfs(cur->l);
    };
    expose(x);
    dfs(x);
    return vs;
  }

  void set_propagate(Node *t, const OperatorMonoid &x) {
    expose(t);
    propagate(t, x);
    push(t);
  }
};


int main() {
  int N, Q;
  cin >> N >> Q;
  struct submax {
    int64 lsum, rsum, ans, all;
  } e{-infll, -infll, -infll, 0};
  auto f = [](const submax &a, const submax &b) {
    submax c;
    c.ans = max({a.ans, b.ans, a.rsum + b.lsum});
    c.all = a.all + b.all;
    c.lsum = max(a.lsum, a.all + b.lsum);
    c.rsum = max(b.rsum, b.all + a.rsum);
    return c;
  };
  auto g = [](submax a, int64 b, int p) {
    a.ans = max(b, b * p);
    a.all = b * p;
    a.lsum = a.ans;
    a.rsum = a.ans;
    return a;
  };
  auto h = [](int64 a, int64 b) {
    return b;
  };
  auto s = [](submax a) {
    swap(a.lsum, a.rsum);
    return a;
  };
  using LCT = LinkCutTree< submax, int64, decltype(f), decltype(g), decltype(h), decltype(s) >;
  LCT lct(f, g, h, s, e, infll);
  vector< LCT::Node * > nodes;
  for(int i = 0; i < N; i++) {
    int x;
    cin >> x;
    nodes.emplace_back(lct.make_node(i, g(e, x, 1)));
  }
  for(int i = 1; i < N; i++) {
    int x, y;
    cin >> x >> y;
    --x, --y;
    lct.evert(nodes[y]);
    lct.link(nodes[y], nodes[x]);
  }
  while(Q--) {
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    --b, --c;
    lct.evert(nodes[b]);
    lct.expose(nodes[c]);
    if(a == 1) {
      lct.set_propagate(nodes[c], d);
    } else {
      cout << nodes[c]->sum.ans << "\n";
    }
  }
}





Measured memory_bytes: 29460