Most Visited Sector in a Circular Track

Given an integer n and an integer array rounds. We have a circular track that consists of n sectors labeled from 1 to n. A marathon will be held on this track, the marathon consists of m rounds. The ith round starts at sector rounds[i - 1] and ends at sector rounds[i]. For example, round 1 starts at sector rounds[0] and ends at sector rounds[1]

Return an array of the most visited sectors sorted in ascending order.

Notice that you circulate the track in ascending order of sector numbers in the counter-clockwise direction (See the first example).

Example 1:

Input: n = 4, rounds = [1,3,1,2]
Output: [1,2]
Explanation: The marathon starts at sector 1. The order of the visited sectors is as follows:
1 --> 2 --> 3 (end of round 1) --> 4 --> 1 (end of round 2) --> 2 (end of round 3 and the marathon)
We can see that both sectors 1 and 2 are visited twice and they are the most visited sectors. Sectors 3 and 4 are visited only once.

Example 2:

Input: n = 2, rounds = [2,1,2,1,2,1,2,1,2]
Output: [2]

Approach

C++

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

vector<int> mostVisited(int n, vector<int> &rounds)
{
    vector<int> mostVisited;
    int start = rounds[0];
    int end = rounds.back();
    if (start <= end)
    {
        for (int i = start; i <= end; ++i)
            mostVisited.push_back(i);
    }
    else
    {
        for (int i = 1; i <= n; ++i)
        {
            if (i >= start || i <= end)
                mostVisited.push_back(i);
        }
    }
    return mostVisited;
}

int main()
{
    int n = 4;
    vector<int> rounds = {1, 3, 1, 2};

    vector<int> res = mostVisited(n, rounds);

    cout << "[";
    for (int i = 0; i < res.size(); i++)
    {
        cout << res[i];
        if (i != res.size() - 1)
            cout << ",";
    }
    cout << "]";

    return 0;
}