kkanyo/coding_test

Study for coding-test

Practice for coding-test

I commit here solved problem at coding-test site.

These codes may not be the perfect answer!

If you have better answer and share that, I appreciated for.

• HackerRank Profile: https://www.hackerrank.com/kkanyo33

coding_test's Issues

Attending_Workshops: Time limit exceeded

When the number of test case is too many, time limit exceed.
So, need to optimize this code.

// need to optimize
int CalculateMaxWorkshops(Available_Workshops* ptr) {
    int currentTime = 0;
    int result = 0;
    
    for (int i=0; i < (ptr->n)-1; i++) {    // sort by endTime
        for (int j=i+1; j < ptr->n; j++) {  // Earliest end time first
            struct Workshop tmp;
            if (ptr->arrWs[i].endTime > ptr->arrWs[j].endTime) {
                tmp = ptr->arrWs[i];
                ptr->arrWs[i] = ptr->arrWs[j];
                ptr->arrWs[j] = tmp;
            }
        }
    }
    
    for (int i=0; i < ptr->n; i++) {    
        if (currentTime <= ptr->arrWs[i].startTime) {   //pass the workshop already start
            currentTime = ptr->arrWs[i].endTime;
            result++;
        }
    }
    
    return result;
}

Now, time complexity of 'CalculateMaxWorkshops' function is O(n^2).

Time limit exceeded

This code did not execute within the time limits. Please optimize your code.
It works only when the number of samples is small.

Because, This code's time complexity is 'O(n^2)'.

    while (i < n) {
        subArr.push_back(arr[i++]);

        for (auto j : subArr) {         //O(n^2), Not effective
            if (j > max) { max = j; }
        }
        cout << max << " ";
        
        max = 0;
        subArr.pop_front();
    }

Magic Spells: Do not work correctly about generic spell of some test case

When the generic spells input consecutively, somtimes, result about one of the generic spell is incorrect.
However, If only input the it with problem, it works correctly.

else {  // For generic spells
        // find the longest common subsequence using dynamic programming
        string scrollName_ = spell->revealScrollName();
        string journal_ = SpellJournal::read();
        long long scrollNameSize = scrollName_.size();
        long long journalSize = journal_.size();
        int table[journalSize+1][scrollNameSize+1];
        
        for (int i = 0; i < scrollNameSize; i++) { table[0][i] = 0; }
        for (int i = 0; i < journalSize; i++) { table[i][0] = 0; }
        
        for (int i = 1; i <= journalSize; i++) {
            for (int j = 1; j <= scrollNameSize; j++) {
                if (journal_[i-1] == scrollName_[j-1]) {
                    table[i][j] = table[i-1][j-1] + 1;
                }
                else { 
                    table[i][j] = max(table[i-1][j], table[i][j-1]);
                }
            }
        }
        cout << table[journalSize][scrollNameSize] << endl;
    }

This code related to find a longest subsequence of letters that are contained in both the spell name and spell journal.
I think problem is in this code.
Need to find cause of error and optimize that code.