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Of the maps bundled with Java, both of the implementations that implement SortedMap also implement NavigableMap. Interface versus concrete class. s SortedMap the best answer? TreeMap? As others mentioned, SortedMap is an interface while TreeMap is one of multiple implementations of that interface (and of the more recent NavigableMap.
Note that in your post you made a mistake. I know that maximum and minimum keys can be retrieved from a TreeMap in O (1) time as follows: int maxKey = tree.lastEntry().getKey(); int minKey = tree.firstEntry().getKey(); I think the time complexity should be O(lgn). The source code of getLastEntry: /**.
implements SortedMap<K,V>, Cloneable, Serializable. In NUT-SHELL HashMap : gives data in O (1) , no ordering. TreeMap : gives data in O (log N), base 2. with ordered keys. LinkedHashMap : is Hash table with linked list (think of indexed-SkipList) capability to store data in the way it gets inserted in the tree.
May 19, 2010 · if the TreeMap will only pass the key to Comparator, would it feasible if i make a reference of the TreeMap in comparator's constructor, then using the key to get the value, something like this(not sure how to pass by reference) : class byValue implements Comparator { TreeMap theTree; public byValue(TreeMap theTree) { this.theTree = theTree ...
Mar 15, 2010 · provide ordered iteration. higherKey (), lowerKey () can be used to get the successor and predecessor of a given key. To sum, the biggest difference between HashMap and TreeMap is that TreeMap implements NavigableMap<K,V>, which provide the feature of ordered iteration. Besides, both HashMap and TreeMap are members of Java Collection framework.
Apr 26, 2016 · As mentioned in the java docs, the TreeMap: is sorted according to the natural ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used. So, you will need to create your own Comparator, that sorts elements on descending order and pass that to the respective TreeMap constructor.
Dec 7, 2012 · TreeMap. A Red-Black tree based NavigableMap implementation. The map is sorted according to the natural ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used. This implementation provides guaranteed log (n) time cost for the containsKey, get, put and remove operations.
Feb 4, 2019 · 1. You should create a unique comparator for comparing the keys of the map. But because you want to print the values too, you should compare the whole entrysets instead: Comparator<Map.Entry<String, String>> c = new Comparator<Map.Entry<String, String>>() {. @Override.
Maps.filterKeys(treeMap, new Predicate<K>() { @Override public boolean apply(K key) { return false; //return true here if you need the entry to be in your new map }}); You can use filterEntries instead if you need the value as well.
Mar 4, 2016 · Herms, it would depend on the efficiency of the datastructures involved. In-place sorting an array using random-pivot quicksort is a FAAAST n log n, but Java's TreeMap is an also pretty fast n log n. Java's HashMap works at a pretty slow n.
