using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using StringBuilder = System.Text.StringBuilder;
//using System.Numerics;

namespace Program
{
    public class Solver
    {
        public void Solve()
        {
            var n = sc.Integer();
            var m = sc.Integer();
            var G = new HeavyLightDecomposition(n);
            var A = sc.Integer(n);
            for (int i = 0; i < n - 1; i++)
            {
                var a = sc.Integer() - 1;
                var b = sc.Integer() - 1;
                G.AddEdge(a, b);
            }
            G.ComputeSubTreeSize(0);
            G.Decomposite(new Edge(-1, 0), -1, 0, 0);
            G.BuildLCA();
            G.BuildHLLCA();
            for (int i = 0; i < n; i++)
            {
                G.Update(i, i, A[i]);
            }
            for (int i = 0; i < m; i++)
            {
                var t = sc.Integer();
                var a = sc.Integer() - 1;
                var b = sc.Integer() - 1;
                var c = sc.Integer();
                var lca = G.GetLCA(a, b);
                if (t == 1)
                {
                    //Debug.WriteLine("{0}->{1} {2}", a, b, c);
                    G.Update(lca, a, c);
                    G.Update(lca, b, c);
                }
                else
                {
                    var l = G.Query(lca, a);
                    var r = G.Query(lca, b);
                    var max = Math.Max(l.Value, r.Value);
                    if (lca != a && lca != b)
                        max = Math.Max(max, l.Key + r.Key - G.Query(lca, lca).Key);
                    IO.Printer.Out.WriteLine(max);
                }
            }
        }
        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region Ex
namespace Program.IO
{
    using System.IO;
    using System.Text;
    using System.Globalization;
    public class Printer : StreamWriter
    {
        static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; }
        public static Printer Out { get; set; }
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
        public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
        public void Write<T>(string format, IEnumerable<T> source) { base.Write(format, source.OfType<object>().ToArray()); }
        public void WriteLine<T>(string format, IEnumerable<T> source) { base.WriteLine(format, source.OfType<object>().ToArray()); }
    }
    public class StreamScanner
    {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read()
        {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while (b < 33 || 126 < b); return (char)b; }

        public string Scan()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public long Long()
        {
            if (isEof) return long.MinValue;
            long ret = 0; byte b = 0; var ng = false;
            do b = read();
            while (b != '-' && (b < '0' || '9' < b));
            if (b == '-') { ng = true; b = read(); }
            for (; true; b = read())
            {
                if (b < '0' || '9' < b)
                    return ng ? -ret : ret;
                else ret = ret * 10 + b - '0';
            }
        }
        public int Integer() { return (isEof) ? int.MinValue : (int)Long(); }
        public double Double() { return double.Parse(Scan(), CultureInfo.InvariantCulture); }
        private T[] enumerate<T>(int n, Func<T> f)
        {
            var a = new T[n];
            for (int i = 0; i < n; ++i) a[i] = f();
            return a;
        }

        public char[] Char(int n) { return enumerate(n, Char); }
        public string[] Scan(int n) { return enumerate(n, Scan); }
        public double[] Double(int n) { return enumerate(n, Double); }
        public int[] Integer(int n) { return enumerate(n, Integer); }
        public long[] Long(int n) { return enumerate(n, Long); }
    }
}
static class Ex
{
    static public string AsString(this IEnumerable<char> ie) { return new string(System.Linq.Enumerable.ToArray(ie)); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") { return string.Join(st, ie.Select(x => x.ToString()).ToArray()); }
    static public void Main()
    {
        var solver = new Program.Solver();
        solver.Solve();
        Program.IO.Printer.Out.Flush();
    }
}
#endregion

#region HLDecomposition
public struct Edge
{
    public int from, to;
    public Edge(int f, int t)
    {
        from = f; to = t;
    }
    public override string ToString()
    {
        return string.Format("{0}->{1}", from, to);
    }
}
public class HeavyLightDecomposition
{
    public void Update(int from, int to, int val)
    {
        var f = go[from];
        var t = go[to];
        if (f.id == t.id)
        {
            f.seg.Update(pos[from], pos[to] + 1, val);
        }
        else
        {
            var ch = GetAncestorAt(t, f.depth + 1);
            var med = H[ch];
            f.seg.Update(pos[from], pos[med.light.from] + 1, val);
            Update(med.light.to, to, val);
        }

    }
    public KeyValuePair<long, long> Query(int from, int to)
    {
        var f = go[from];
        var t = go[to];
        if (f.id == t.id)
        {
            var l = f.seg.QueryLeft(pos[from], pos[to] + 1);
            var max = f.seg.Query(pos[from], pos[to] + 1);
            return new KeyValuePair<long, long>(l, max);
        }
        else
        {
            var ch = GetAncestorAt(t, f.depth + 1);
            var med = H[ch];
            var l = f.seg.QueryLeft(pos[from], pos[med.light.from] + 1);
            var lsum = f.seg.QuerySum(pos[from], pos[med.light.from] + 1);
            var r = Query(med.light.to, to);
            var lmax = Math.Max(l, lsum + r.Key);
            var max = Math.Max(lmax, r.Value);
            max = Math.Max(max, f.seg.QueryRight(pos[from], pos[med.light.from] + 1) + r.Key);
            max = Math.Max(max, f.seg.Query(pos[from], pos[med.light.from] + 1));
            return new KeyValuePair<long, long>(lmax, max);
        }
    }

    List<Edge>[] G;
    List<Node> H = new List<Node>();
    int[] subTreeSize;
    int[] par;
    int[] pos;
    int[,] parent;
    int[] depth;

    Node[] go;
    int[,] hlpar;
    public HeavyLightDecomposition(int n)
    {
        G = Enumerate(n, x => new List<Edge>());
        subTreeSize = new int[n];
        pos = new int[n];
        depth = new int[n];
        par = new int[n];
        parent = new int[32, n];
        go = new Node[n];
    }
    public void AddEdge(int f, int t)
    {
        G[f].Add(new Edge(f, t));
        G[t].Add(new Edge(t, f));
    }
    public void ComputeSubTreeSize(int root)
    {
        var stack = new Stack<KeyValuePair<int, int>>();
        stack.Push(new KeyValuePair<int, int>(root, -1));
        var visit = new bool[G.Length];
        while (stack.Any())
        {
            var p = stack.Pop();
            var cur = p.Key;
            var prev = p.Value;
            if (visit[p.Key])
            {
                foreach (var next in G[cur])
                {
                    var to = To(next);
                    if (to != prev)
                        subTreeSize[cur] += subTreeSize[to];
                }
            }
            else
            {
                visit[cur] = true;
                stack.Push(new KeyValuePair<int, int>(cur, prev));
                subTreeSize[cur]++;
                foreach (var next in G[cur])
                {
                    var to = To(next);
                    if (to != prev) stack.Push(new KeyValuePair<int, int>(to, cur));
                }
            }
        }
    }
    public void Decomposite(Edge light, int prevId, int d, int lv)
    {
        var node = new Node();
        node.light = light;
        node.id = H.Count;
        node.par = prevId;
        node.depth = lv;
        H.Add(node);
        var prev = light.from;
        var cur = light.to;
        while (cur != prev)
        {
            var next = cur;
            var max = 0;
            depth[cur] = d;
            par[cur] = prev;
            go[cur] = node;
            pos[cur] = node.heavy.Count;
            foreach (var to in G[cur])
            {
                var t = To(to);
                if (t != prev) max = Math.Max(max, subTreeSize[t]);
            }
            foreach (var to in G[cur])
            {
                var t = To(to);
                if (t == prev) continue;
                if (max == subTreeSize[t])
                {
                    //Debug.WriteLine("{0}->{1}", cur, t);
                    max = 1 << 30;
                    next = t;
                    node.heavy.Add(to);
                }
                else Decomposite(to, node.id, d + 1, lv + 1);
            }
            prev = cur;
            cur = next;
            d++;
        }
        node.init();

    }
    public void BuildLCA()
    {
        for (int k = 0; k < 31; k++)
            for (int v = 0; v < G.Length; v++)
                parent[k, v] = -1;
        for (int i = 0; i < G.Length; i++)
            parent[0, i] = par[i];
        for (int k = 0; k < 31; k++)
        {
            for (int v = 0; v < G.Length; v++)
                if (parent[k, v] < 0) parent[k + 1, v] = -1;
                else parent[k + 1, v] = parent[k, parent[k, v]];
        }

    }
    public void BuildHLLCA()
    {
        hlpar = new int[32, H.Count];
        for (int k = 0; k < 31; k++)
            for (int v = 0; v < H.Count; v++)
                hlpar[k, v] = -1;
        for (int i = 0; i < H.Count; i++)
            hlpar[0, i] = H[i].par;
        for (int k = 0; k < 31; k++)
        {
            for (int v = 0; v < H.Count; v++)
                if (hlpar[k, v] < 0) hlpar[k + 1, v] = -1;
                else hlpar[k + 1, v] = hlpar[k, hlpar[k, v]];
        }

    }
    public int GetAncestorAt(Node v, int d)
    {
        if (v.depth < d)
            throw new Exception();
        for (int i = 0; i < 32; i++)
            if ((((v.depth - d) >> i) & 1) == 1)
                v = H[hlpar[i, v.id]];
        return v.id;
    }


    public int To(Edge t) { return t.to; }


    public int GetLCA(int u, int v)
    {
        if (depth[u] > depth[v]) { var tmp = u; u = v; v = tmp; }
        for (int k = 0; k < 32; k++)
            if ((((depth[v] - depth[u]) >> k) & 1) == 1)
                v = parent[k, v];
        if (u == v)
            return u;
        for (int i = 31; i >= 0; i--)
            if (parent[i, u] != parent[i, v])
            {
                u = parent[i, u];
                v = parent[i, v];
            }
        return parent[0, u];
    }
    public int GetAncestor(int v, int k)
    {
        var to = depth[v] - k;
        for (int i = 0; i < 32; i++)
            if ((((depth[v] - to) >> i) & 1) == 1)
                v = parent[i, v];
        return v;
    }
    public int GetAncestorAt(int v, int d)
    {
        if (depth[v] < d)
            throw new Exception();
        for (int i = 0; i < 32; i++)
            if ((((depth[v] - d) >> i) & 1) == 1)
                v = parent[i, v];
        return v;
    }
    static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }

}
#endregion
public class Node
{
    public Edge light;
    public List<Edge> heavy = new List<Edge>();
    public int par;
    public int depth;
    public int id;
    public LazyEvaluateRangeAddSegmentTree seg;
    public void init()
    {
        seg = new LazyEvaluateRangeAddSegmentTree(heavy.Count + 1);
    }
    public override string ToString()
    {
        var s = new List<int>();
        s.Add(light.from);
        s.Add(light.to);
        foreach (var e in heavy)
            s.Add(e.to);
        return s.AsJoinedString("->");
    }
}

#region LazyEvaluateRangeAddSegmentTree
public class LazyEvaluateRangeAddSegmentTree
{
    int n;
    long[] sum;
    long[] left, right, ans;
    long[] lazy;
    public LazyEvaluateRangeAddSegmentTree(int size)
    {
        n = 1;
        while (n < size)
            n <<= 1;
        sum = new long[n << 1];
        lazy = new long[n << 1];
        for (int i = 0; i < lazy.Length; i++)
            lazy[i] = int.MinValue;
        left = new long[n << 1];
        right = new long[n << 1];
        ans = new long[n << 1];
    }
    private void lazyEval(int k, int a, int b)
    {
        if (lazy[k] == int.MinValue)
            return;
        Update(a, (a + b) >> 1, lazy[k], k << 1, a, (a + b) >> 1);
        Update((a + b) >> 1, b, lazy[k], (k << 1) + 1, (a + b) >> 1, b);
        lazy[k] = int.MinValue;
    }
    private void eval(int k)
    {
        int l = k << 1, r = (k << 1) + 1;
        ans[k] = Math.Max(Math.Max(ans[l], ans[r]), left[r] + right[l]);
        sum[k] = sum[l] + sum[r];
        left[k] = Math.Max(sum[l] + left[r], left[l]);
        right[k] = Math.Max(sum[r] + right[l], right[r]);
    }
    public void Update(int a, int b, int v)
    {
        Update(a, b, v, 1, 0, n);
    }
    private void Update(int a, int b, long v, int k, int l, int r)
    {
        if (r <= a || b <= l)
            return;
        else if (a <= l && r <= b)
        {
            lazy[k] = v;
            sum[k] = lazy[k] * (r - l);
            left[k] = right[k] = ans[k] = lazy[k] >= 0 ? (r - l) * lazy[k] : lazy[k];
        }
        else
        {
            lazyEval(k, l, r);
            Update(a, b, v, k << 1, l, (l + r) >> 1);
            Update(a, b, v, (k << 1) + 1, (l + r) >> 1, r);
            eval(k);
        }
    }
    public long Query(int a, int b) { return Query(a, b, 1, 0, n); }
    private long Query(int a, int b, int k, int l, int r)
    {
        if (r <= a || b <= l)
            return int.MinValue;
        if (a <= l && r <= b)
            return ans[k];
        else
        {
            lazyEval(k, l, r);
            var vl = Query(a, b, k << 1, l, (l + r) >> 1);
            var vr = Query(a, b, (k << 1) + 1, (l + r) >> 1, r);
            var vll = QueryRight(a, b, k << 1, l, (l + r) >> 1);
            var vrr = QueryLeft(a, b, (k << 1) + 1, (l + r) >> 1, r);
            eval(k);
            return Math.Max(Math.Max(vl, vr), vll + vrr);
        }
    }
    public long QuerySum(int a, int b) { return QuerySum(a, b, 1, 0, n); }
    private long QuerySum(int a, int b, int k, int l, int r)
    {
        if (r <= a || b <= l)
            return 0;
        if (a <= l && r <= b)
            return sum[k];
        else
        {
            lazyEval(k, l, r);
            var vl = QuerySum(a, b, k << 1, l, (l + r) >> 1);
            var vr = QuerySum(a, b, (k << 1) + 1, (l + r) >> 1, r);
            eval(k);
            return vl + vr;
        }
    }
    public long QueryLeft(int a, int b) { return QueryLeft(a, b, 1, 0, n); }
    private long QueryLeft(int a, int b, int k, int l, int r)
    {
        if (r <= a || b <= l)
            return int.MinValue;
        if (a <= l && r <= b)
            return left[k];
        else
        {
            lazyEval(k, l, r);
            var vl = QueryLeft(a, b, k << 1, l, (l + r) >> 1);
            var lsum = QuerySum(a, b, k << 1, l, (l + r) >> 1);
            var vr = QueryLeft(a, b, (k << 1) + 1, (l + r) >> 1, r);
            eval(k);
            return Math.Max(vl, lsum + vr);
        }
    }
    public long QueryRight(int a, int b) { return QueryRight(a, b, 1, 0, n); }
    private long QueryRight(int a, int b, int k, int l, int r)
    {
        if (r <= a || b <= l)
            return int.MinValue;
        if (a <= l && r <= b)
            return right[k];
        else
        {
            lazyEval(k, l, r);
            var vl = QueryRight(a, b, k << 1, l, (l + r) >> 1);
            var vr = QueryRight(a, b, (k << 1) + 1, (l + r) >> 1, r);
            var rsum = QuerySum(a, b, (k << 1) + 1, (l + r) >> 1, r);
            eval(k);
            return Math.Max(vl + rsum, vr);
        }
    }
}
#endregion


Measured memory_bytes: 168548