3. Map & Multimap

Principle: Red-Black Tree

Header: #include <map>

Methods: find(), count(), empty(), equal_rage()

Associated: std::next(), std::prev(), std::distance()

Feature: Map's key must be unique, multimap's key can be duplicated.

Code example:

#include "solution.hpp"
#include <iostream>
#include <map>

bool checkMultipleOccurrences(const std::string& fruit) {
    // Create a multimap with fruits as keys and their counts as values
    std::multimap<std::string, int> fruitMap = {
        {"apple", 5},
        {"banana", 2},
        {"apple", 3},
        {"orange", 4},
        {"apple", 4}
    };

    // TODO: Determine if the given fruit has multiple values and return true or false
    /*
    if (fruitMap.count(fruit) > 1) {
        return true;
    } else {
        return false;
    }
    */
    
    auto range = fruitMap.equal_range(fruit);
    if (std::distance(range.first, range.second) > 1) {
        return true;
    } else {
        return false;
    }
}

int main() {
    bool result = checkMultipleOccurrences("apple");
    if (result) {
        std::cout << "Multiple occurrences found." << std::endl;
    } else {
        std::cout << "No multiple occurrences." << std::endl;
    }
    return 0;
}

#include "solution.hpp"

std::map<std::string, int> count_event_frequency(const std::multimap<std::string, std::string>& events) {
    // TODO: Implement logic to return the frequency count of each date in the multimap.
    std::map<std::string, int> map;
    
    // multimap에서 꺼내서 map의 키를 검사 후 넣어
    for (const auto& event : events) {
        int count = map.count(event.first);
        if (map.count(event.first) != 0) {
            map.erase(event.first);
        }
        
        map.insert({event.first, count+1});   
    }
    
    return map;
}

int main() {
    // Create a multimap containing dates and their respective events
    std::multimap<std::string, std::string> events = {
        {"2023-06-11", "Seminar"},
        {"2023-06-11", "Workshop"},
        {"2023-06-21", "Concert"},
        {"2023-07-12", "Conference"},
        {"2023-07-12", "Meeting"}
    };

    // Get the frequency count of events on each date
    std::map<std::string, int> frequency_count = count_event_frequency(events);

    // Display the frequency count of events
    for (const auto& date : frequency_count) {
        std::cout << date.first << ": " << date.second << std::endl;
    }
    
    return 0;
}