Петя и карточки

#pragma once
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <vector>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <queue>
#include <stack>
#include <climits>
#include <deque>
#include <ctime>
#include <iomanip>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <fstream>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;

#define mh() make_heap()
#define poph() pop_heap()
#define pushh() push_heap()
#define sor(n) n.begin(), n.end()
#define rsor(n) n.rbegin(), n.rend()
#define mp make_pair
#define files freopen("input.txt", "rt", stdin); freopen("output.txt", "wt", stdout)
#define p(T) pair<T,T>
#define toch(x) cout.precision(x), cout.setf(ios::fixed)
#define znac(l) abs(l)/l
#define IOS ios::sync_with_stdio(false)
#define IOSB cin.tie(0), cout.tie(0);
const ll ok = ll(1e9 + 7);
string t[2 * 131072];
void add(int pos, string new_val) {
    pos += 131071;
    t[pos] = new_val;
    for (pos = pos >> 1; pos; pos = pos >> 1)
    {
        string p = t[pos];
        t[pos] =  t[pos << 1]+ t[(pos << 1) + 1];
        if (p == t[pos])
            break;
    }
}

void del(int pos) {
    pos += 131071;
    t[pos] = "";
    for (pos = pos >> 1; pos; pos = pos >> 1)
    {
        string p = t[pos];
        t[pos] = t[pos << 1] + t[(pos << 1) + 1];
        if (p == t[pos])
            break;
    }
}

string sumotr(ll tl, ll tr, ll pos, ll nl, ll nr)
{
    if (tl == nl && tr == nr)
        return t[pos];
    else
        if (tl > tr)
            return"";
    ll nm = (nl + nr) >> 1;
    string sum = "";
    sum += sumotr(tl, min(nm, tr), pos << 1, nl, nm);
    sum += sumotr(max(nm + 1, tl), tr, (pos << 1) + 1, nm + 1, nr);
    return sum;
}

int main()
{
    IOSB;
    IOS;
#ifdef TheCompiler
    files;
#endif
    ll n;
    cin >> n;
    stack<ll>last;
    map<string, ll>z;
    ll k = 1;
    for (int i = 1; i <= n; i++)
    {
        string a;
        cin >> a;
        if (a == "more")
        {
            cin >> a;
            add(k, a);
            z[a] = k;
            k++;
        }
        else
            if (a == "del")
            {
                cin >> a;
                if (z.find(a) != z.end()&&z[a] != -1 )
                {
                    del(z[a]);
                    z[a] = -1;
                }
                else
                    cout << "You stupid" << endl;
            }
            else
                if (a == "chng")
                {
                    string b;
                    cin >> a >> b;
                    add(z[a], b);
                }
            else
            {
                ll t1, t2;
                cin >> t1 >> t2;
                cout << sumotr(t1, t2, 1, 1, 131072) << endl;
            }
    }
    return 0;
}