What is the main task of the Map data structure and what is its advantage?

The main task of the Map data structure is to store "key-value" pairs with the ability to quickly access a value by its key. The advantage of Map is that it provides efficient search, insertion, and deletion of elements, usually in near-constant time (O(1)), which is significantly faster than list traversal.

Example of using Map in Java:

import java.util.HashMap;

public class Example {
    public static void main(String[] args) {
        Map<String, Integer> map = new HashMap<>();
        map.put("apple", 3);
        map.put("banana", 5);

        int count = map.get("apple"); // Get the value by the key "apple"
        System.out.println("Number of apples: " + count);
    }
}