Practice›Java Fundamentals›Module 10. Collections›10.1 HashMap

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10.1 HashMap — build a frequency map

Total: 0 / 3 pts

Practice mode — check each part and get hints as you go.

Task

Fill in countWords so that it returns a map from each distinct word to how many times it appears.

Hint: getOrDefault(word, 0) + 1 makes the first occurrence start at 1. The program looks values up by key — never rely on the order of a map.

Your solution

import java.util.HashMap;
import java.util.Map;

public class Main {

    public static Map<String, Integer> countWords(String[] words) {
        // count how many times each word appears

    }

    public static void main(String[] args) {
        Map<String, Integer> c = countWords(new String[]{"a", "b", "a", "a"});
        System.out.println(c.get("a"));
        System.out.println(c.get("b"));
        System.out.println(c.size());
    }
}

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