frequency_queries.cpp

#include <bits/stdc++.h>


using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

vector<int> freqQuery(vector<vector<int>> queries) {
   
    int q;
    int type;
    int current_count;
    vector<int> query;
    vector<int> query_results;
    unordered_map<long, int> count_map;
    unordered_map<int, long> frequency_map;
    
    q = queries.size();
    
    for(int i =0 ; i < q ;i++){
        query = queries[ i ];
        type = query[0];
        switch(type){
            case 1:
                frequency_map[count_map[ query[1] ]]--;
                count_map[ query[1] ]++;
                frequency_map[count_map[ query[1] ]]++;
                
                break;
            case 2:
                current_count = count_map[ query[1] ];
                if(current_count > 0){
                    frequency_map[current_count]--;
                    count_map[ query[1] ]--;
                    frequency_map[count_map[ query[1] ]]++;
                }
                break;
            case 3:
                query_results.push_back(( frequency_map[query[1]] > 0 )? 1:0); 
                break;
            default:
                break;
        }   
        
    }
    return query_results;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string q_temp;
    getline(cin, q_temp);

    int q = stoi(ltrim(rtrim(q_temp)));

    vector<vector<int>> queries(q);

    for (int i = 0; i < q; i++) {
        queries[i].resize(2);

        string queries_row_temp_temp;
        getline(cin, queries_row_temp_temp);

        vector<string> queries_row_temp = split(rtrim(queries_row_temp_temp));

        for (int j = 0; j < 2; j++) {
            int queries_row_item = stoi(queries_row_temp[j]);

            queries[i][j] = queries_row_item;
        }
    }

    vector<int> ans = freqQuery(queries);

    for (int i = 0; i < ans.size(); i++) {
        fout << ans[i];

        if (i != ans.size() - 1) {
            fout << "\n";
        }
    }

    fout << "\n";

    fout.close();

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}

vector<string> split(const string &str) {
    vector<string> tokens;

    string::size_type start = 0;
    string::size_type end = 0;

    while ((end = str.find(" ", start)) != string::npos) {
        tokens.push_back(str.substr(start, end - start));

        start = end + 1;
    }

    tokens.push_back(str.substr(start));

    return tokens;
}