CodingChallengesSolutions/hackerrank/hashmap/frequency_query1.cpp at master · NicolaBernini/CodingChallengesSolutions · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151

// Solution to Frequency Query
// https://www.hackerrank.com/challenges/frequency-queries/

#include <bits/stdc++.h>
#include <unordered_map>
using namespace std;

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

// Complete the freqQuery function below.
vector<int> freqQuery(vector< vector<int> > queries)
{
    unordered_map<int, unsigned int> obs;
    unordered_map<unsigned int, unsigned int> freq;

    vector<int> res;

    for(const auto& q : queries)
    {
        if(q[0] == 1)
        {
            if(obs.find(q[1]) == obs.end())
            {
                obs[q[1]] = 1;

                if(freq.find(1) == freq.end()) freq[1] = 1;
                else freq[1]++;
            }
            else
            {
                freq[obs[q[1]]]--;
                obs[q[1]]++;
                if(freq.find(obs[q[1]]) == freq.end()) freq[obs[q[1]]] = 1;
                else freq[obs[q[1]]]++;
            }

        }
        else if(q[0] == 2)
        {
            if(obs.find(q[1]) != obs.end())
            {
                freq[obs[q[1]]]--;
                obs[q[1]]--;
                if(obs[q[1]] > 0)
                {
                    if(freq.find(obs[q[1]]) == freq.end()) freq[obs[q[1]]] = 1;
                    else freq[obs[q[1]]]++;
                }
                else
                {
                    obs.erase(q[1]);
                }
            }
        }
        else if(q[0] == 3)
        {
            res.push_back((freq[q[1]]>0)?1:0);
        }
        else
        {
            throw std::runtime_error("Unexpected");
        }
    }

    return res;
}

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;
}