将Map<K、V>转换为Map<V、List<K>>

import java.util.*;

public class MapConverter {
    public static <K, V> Map<V, List<K>> convert(Map<K, V> originalMap) {
        Map<V, List<K>> convertedMap = new HashMap<>();

        for (Map.Entry<K, V> entry : originalMap.entrySet()) {
            K key = entry.getKey();
            V value = entry.getValue();

            if (convertedMap.containsKey(value)) {
                convertedMap.get(value).add(key);
            } else {
                List<K> keyList = new ArrayList<>();
                keyList.add(key);
                convertedMap.put(value, keyList);
            }
        }

        return convertedMap;
    }

    public static void main(String[] args) {
        Map<String, Integer> originalMap = new HashMap<>();
        originalMap.put("A", 1);
        originalMap.put("B", 2);
        originalMap.put("C", 1);
        originalMap.put("D", 3);

        Map<Integer, List<String>> convertedMap = convert(originalMap);

        for (Map.Entry<Integer, List<String>> entry : convertedMap.entrySet()) {
            Integer value = entry.getKey();
            List<String> keyList = entry.getValue();

            System.out.println("Value: " + value);
            System.out.println("Keys: " + keyList);
            System.out.println();
        }
    }
}

Value: 1
Keys: [A, C]

Value: 2
Keys: [B]

Value: 3
Keys: [D]