Kattis challenge to finding the number of different elements in a set

Question

I have started doing Kattis challenges from their website. For now I am still at the low complexity ones.

The first line of input contains a single positive integer T≤50 indicating the number of test cases. The first line of each test case also contains a single positive integer n indicating the number of elements available for the test case.

Elements only contain lowercase letters, have at least one letter, and do not contain spaces.

The number elements for a test case is at most 100 and each element contains no more than 20 characters.

For each test case, I have to output a single line containing a single integer that is the number of distinct elements found in the specific test case.

To view the challenge follow this link: I've Been Everywhere, Man

Sample input:

2
7
saskatoon
toronto
winnipeg
toronto
vancouver
saskatoon
toronto
3
edmonton
edmonton
edmonton

Sample output:

4
1

Here is the code:

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using std::cin;
using std::cout;
using std::vector;
using std::string;

int main()
{
    int testCasesCount = 0, tripsCount = 0;
    vector<string> trips;
    vector<int> testCasesResults;

    cin >> testCasesCount;

    for (int i = 0; i < testCasesCount; i++) {
        cin >> tripsCount;

        string destination;
        int uniqueCount = 0;
        for (int j = 0; j < tripsCount; j++) {
            cin >> destination;

            if (std::find(trips.begin(), trips.end(), destination) == trips.end())
                trips.push_back(destination);
        }

        testCasesResults.push_back(uniqueCount);
    }

    for (unsigned int i = 0; i < testCasesResults.size(); i++)
        cout << testCasesResults.at(i) << "\n";

    return 0;
}

The code is working fine, BUT it's kind of ugly, at least that's how I see it.

My first question is to ask if there is a better way to check if an array/vector contains a certain element?

And the second question - can someone give me some tips as to what I can improve and what will be a good idea to avoid?

Answer 1

As you yourself hinted in the question title, you should be using a set. Discarding duplicates using a set is easier and more efficient than using a vector.

Answer 2

If you want to improve things even further, don't add the results to a vector, just print them out as you get them:

int testCasesCount = 0 , tripsCount = 0;
set<string> trips;
cin >> testCasesCount;

for ( int i = 0; i < testCasesCount; i++ ) {
    cin >> tripsCount;
    string destination;
    for ( int j = 0; j < tripsCount; j++ ) {
        cin >> destination;
        //If destination is a duplicate, emplace will just fail.
        trips.emplace( destination );
    }
    cout << trips.size() << '\n';
    trips.clear();
}