Sparse Arrays in C++ HackerRank

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.

For example, given input strings = ['ab, 'ab', 'abc'], and queries = ['ab', 'abc','bc'] , we find instances of 'ab', of 'abc' and of 'bc'. For each query, we add an element to our return array, returns = [2,1,0].

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:

strings - an array of strings to search

queries - an array of query strings

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 .

Constraints

.

Output Format

Return an integer array of the results of all queries in order.

Sample Input 1

4 aba baba aba xzxb 3 aba xzxb ab

Sample Output 1

2 1 0

Explanation 1

Here, "aba" occurs twice, in the first and third string. The string "xzxb" occurs once in the fourth string, and "ab" does not occur at all.

Sample Input 2

3 def de fgh 3 de lmn fgh

Sample Output 2

1 0 1

Source Code in C++

// Complete the matchingStrings function below. vector matchingStrings(vector strings, vector queries) {

vector vect; for(int i=0;i< queries.size();i++){ vect.push_back(0); for(int j=0;j< strings.size(); j++){ if(queries[i]==strings[j]) vect[i]++; } } return vect; }

}

Please explain each line of code and please explain the logic behind each line of code. For example, explain why we need push_back(0) and why there is a 0 inside the parentheses.