Created
July 1, 2022 17:17
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TreeMultiMap: Data structure that (partially) implements a TreeMap with a key and a list of values
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| import java.util.ArrayList; | |
| import java.util.List; | |
| import java.util.Map; | |
| import java.util.TreeMap; | |
| public class TreeMultiMap<K extends Comparable<K>, V> { | |
| private final TreeMap<K, List<V>> treeMap; | |
| int size; | |
| public TreeMultiMap() { | |
| treeMap = new TreeMap<>(Comparable::compareTo); | |
| size = 0; | |
| } | |
| public void put(K key, V value) { | |
| if (treeMap.containsKey(key)) { | |
| treeMap.get(key).add(value); | |
| } else { | |
| treeMap.put(key, new ArrayList<>() {{ | |
| add(value); | |
| }}); | |
| } | |
| size++; | |
| } | |
| public V removeFirst() { | |
| K key = treeMap.firstKey(); | |
| if (key == null) { | |
| return null; | |
| } | |
| size--; | |
| if (treeMap.get(key).size() == 1) { | |
| V value = treeMap.remove(key).get(0); | |
| treeMap.remove(key); | |
| return value; | |
| } else { | |
| return treeMap.get(key).remove(0); | |
| } | |
| } | |
| public List<Map.Entry<K, V>> getAllDescending() { | |
| List<Map.Entry<K, V>> entries = new ArrayList<>(); | |
| for (Map.Entry<K, List<V>> entry : treeMap.descendingMap().entrySet()) { | |
| for (V value : entry.getValue()) { | |
| entries.add(new Map.Entry<>() { | |
| @Override | |
| public K getKey() { | |
| return entry.getKey(); | |
| } | |
| @Override | |
| public V getValue() { | |
| return value; | |
| } | |
| @Override | |
| public V setValue(V value) { | |
| throw new UnsupportedOperationException(); | |
| } | |
| }); | |
| } | |
| } | |
| return entries; | |
| } | |
| public int size() { | |
| return size; | |
| } | |
| } |
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