Old driver tree 80pts求debug

TLE on #5,#6

code:

#include<iostream>
#include<set>
#include<vector>
#include<algorithm>
#include<cstdio>
using namespace std;
typedef long long ll;
#define int long long

const ll mod = 1000000007;
const ll maxn = 100055;

struct node {
    ll l, r;
    mutable ll v;
    node(ll L, ll R = 0, ll V = 0) : l(L), r(R), v(V) {}
    bool operator<(const node& a)const {
        return l < a.l;
    }
};

ll n, v, op, l, r, x;
set<node>odt;

#define IT set<node>::iterator

set<node>::iterator split(int pos) {
    set<node>::iterator it = odt.lower_bound(node(pos));
    if (it != odt.end() && it->l == pos)return it;
    it--;
    if (it->r < pos)return odt.end();
    ll l = it->l;
    ll r = it->r;
    ll v = it->v;
    odt.erase(it);
    odt.insert(node(l, pos - 1, v));
    return odt.insert(node(pos, r, v)).first;
}
void add(ll l, ll r, ll x) {
    set<node>::iterator itr = split(r + 1), itl = split(l);
    for (register set<node>::iterator it = itl; it != itr; it++)it->v += x;
}
void assign(ll l, ll r, ll x) {
    set<node>::iterator itr = split(r + 1), itl = split(l);
    odt.erase(itl, itr);
    odt.insert(node(l, r, x));
}
ll query(ll l, ll r) {
    ll maxn = 1099521627776;
    maxn *= -1;
    set<node>::iterator itr = split(r + 1), itl = split(l);
    for (register set<node>::iterator it = itl; it != itr; it++) {
        maxn = max(maxn, it->v);
    }
    return maxn;
}
signed main() {
    int n, m;
    scanf("%lld%lld", &n, &m);
    for (register int i = 1; i <= n; i++) {
        scanf("%lld", &v);
        odt.insert(node(i, i, v));
    }
    for (register int i = 1; i <= m; i++) {
        scanf("%lld", &op);
        if (op == 1) {
            scanf("%lld%lld%lld", &l, &r, &x);
            assign(l, r, x);
        }
        else if (op == 2) {
            scanf("%lld%lld%lld", &l, &r, &x);
            add(l, r, x);
        }
        else {
            scanf("%lld%lld", &l, &r);
            cout << query(l, r) << endl;
        }
    }
    return 0;
}