Chtholly Tree RE on #7求助/kk

#include <iostream>
#include <set>
#include <vector>
#include <algorithm>
#define int long long
using namespace std;
struct node
{
    int l, r;
    mutable int v;
    node(int L, int R = -1, int V = 0)
    {
        l = L;
        r = R;
        v = V;
    }
};
bool operator<(const node &n, const node &m)
{
    return n.l < m.l;
}
set<node> s;
#define IT set<node>::iterator
IT split(int pos)
{
    IT it = s.lower_bound(node(pos));
    if (it != s.end() && it->l == pos)
        return it;
    it--;
    int l = it->l, r = it->r, v = it->v;
    s.erase(it);
    s.insert(node(l, pos - 1, v));
    return s.insert(node(pos, r, v)).first;
}
void assign(int l, int r, int v = 0)
{
    IT itl = split(l), itr = split(r + 1);
    s.erase(itl, itr);
    s.insert(node(l, r, v));
}
void add(int l, int r)
{
    IT itl = split(l), itr = split(r + 1);
    for (; itl != itr; ++itl)
        itl->v = !itl->v;
}
int n, op, l, r;
signed main()
{
    cin >> n;
    s.insert(node(1, 1e18, 0));
    for (int i = 0; i < n; i++)
    {
        cin >> op >> l >> r;
        if (op == 1)
        {
            assign(l, r, 1);
        }
        if (op == 2)
        {
            assign(l, r, 0);
        }
        if (op == 3)
        {
            add(l, r);
        }
        for (IT iter = s.begin(); iter != s.end(); iter++)
        {
            if (!iter->v)
            {
                cout << iter->l << endl;
                break;
            }
        }
    }
    return 0;
}