Sparse Arrays-HackerRank Solution

 Problem:

There is a collection of input strings and a collection of query strings. For each query string, determine how many times it occurs in the list of input strings. Return an array of the results.

Example

There are  instances of ',  of '' and  of ''. For each query, add an element to the return array, .

Function Description

Complete the function matchingStrings in the editor below. The function must return an array of integers representing the frequency of occurrence of each query string in strings.

matchingStrings has the following parameters:

• string strings[n] - an array of strings to search
• string queries[q] - an array of query strings

Returns

• int[q]: an array of results for each query

Input Format

The first line contains and integer , the size of .
Each of the next  lines contains a string .
The next line contains , the size of .
Each of the next  lines contains a string .

Solution:

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);

string rtrim(const string &);

/*

 * Complete the 'matchingStrings' function below.

 *

 * The function is expected to return an INTEGER_ARRAY.

 * The function accepts following parameters:

 *  1. STRING_ARRAY strings

 *  2. STRING_ARRAY queries

 */

vector<int> matchingStrings(vector<string> strings, vector<string> queries) {

}

int main()

{

    ofstream fout(getenv("OUTPUT_PATH"));

    string strings_count_temp;

    getline(cin, strings_count_temp);

    int strings_count = stoi(ltrim(rtrim(strings_count_temp)));

    vector<string> strings(strings_count);

    for (int i = 0; i < strings_count; i++) {

        string strings_item;

        getline(cin, strings_item);

        strings[i] = strings_item;

    }

    string queries_count_temp;

    getline(cin, queries_count_temp);

    int queries_count = stoi(ltrim(rtrim(queries_count_temp)));

    vector<string> queries(queries_count);

    for (int i = 0; i < queries_count; i++) {

        string queries_item;

        getline(cin, queries_item);

        queries[i] = queries_item;

    }

    vector<int> res = matchingStrings(strings, queries);

    for (size_t i = 0; i < res.size(); i++) {

        fout << res[i];

        if (i != res.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;

}