80分求调， 后两个测试点TLE，有调必关

#include <bits/stdc++.h>
#include <algorithm>
#include <deque>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iostream>
#include <istream>
#include <iterator>
#include <list>
#include <map>
#include <ostream>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include <forward_list>
using namespace std;
forward_list<int> fl;
int n;
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n;
	fl = {1};
	for(int i = 1; i <= n; i++)
	{
		int a, x, y;
		cin >> a;
		if(a == 1)
		{
			cin >> x >> y;
			auto itr = find(fl.begin(), fl.end(), x);
			fl.insert_after(itr, y);
		}
		else if(a == 2)
		{
			cin >> x;
			auto itr = find(fl.begin(), fl.end(), x);
			if (itr != fl.end())
			{
				auto next_itr = next(itr);
				if (next_itr != fl.end())
				{
					cout << *next_itr << endl;
				}
				else
				{
					cout << 0 << endl;
				}
			}
			else
			{
				cout << 0 << endl;
			}
		}
		else
		{
			cin >> x;
			auto itr = find(fl.begin(), fl.end(), x);
			fl.erase_after(itr);
		}
	}
	return 0;
}