multimap

As we now, there is the concept of BiMap and multiMap but is there a multiBiMap ? so what do I mean by this. In multiMap you have one-to-many relationship between K and V, a single key can be associated to multiple value, hence the name. In bi map you have K,V pair which is bi-directional mean you can get V,K relationship as well. Like having a two regular maps but synchronized. I need a bi directional multi map where you combine these two concepts. import java.util.Set; import com.google.common.collect.HashMultimap; import com.google.common.collect.SetMultimap; public class ManyToMany<K, V> {

I am looking for a high-performance, concurrent, MultiMap. I have searched everywhere but I simply cannot find a solution that uses the same approach as ConcurrentHashMap (Only locking a segment of the hash array). The multimap will be both read, added to and removed from often. The multimap key will be a String and it's value will be arbitrary. I need O(1) to find all values for a given key, O(N) is OK for removal, but O(logN) would be preferred. It is crucial that removal of the last value for a given key will remove the container of values from the key, as to not leak memory. HERE'S THE

Suppose I have a list of tuples List[(A, B)] . What is the best way to convert it to a multimap , which maps A to Set[B] ? Can I build an immutable multimap ? Can I build an immutable multimap ? Not with the MultiMap in Scala standard library. Of course, you can write your own. What is the best way to convert it to a multimap? import scala.collection.mutable.{HashMap, Set, MultiMap} def list2multimap[A, B](list: List[(A, B)]) = list.foldLeft(new HashMap[A, Set[B]] with MultiMap[A, B]){(acc, pair) => acc.addBinding(pair._1, pair._2)} I'm a bit confused, Multimap doesn't map A to Set[B] , it

I have two multimaps.i would like to create a new multimap which has the common key-value pairs in the given those two multimaps: for eg: #include <iostream> #include <string> #include <map> using namespace std; int main () { multimap<std::string, std::string> m; multimap<std::string, std::string> n; m.insert(multimap<string,string>::value_type("1-2","1-1")); m.insert(multimap<string,string>::value_type("1-2","1-2")); m.insert(multimap<string,string>::value_type("1-2","1-3")); m.insert(multimap<string,string>::value_type("1-2","1-4")); m.insert(multimap<string,string>::value_type("1-3","2-1"))

I found that they have one key and multiple values which is unique. The multimap stores pairs of (key, value) where both key and value can appear several times. The map<key, set<value>> will only store each value once for a specific key. To do that, it will have to be able to compare the values, not just the keys. It depends on your application if the values that compare equal are equivalent, or if you wish to store them separately anyway. Perhaps they contain fields that are different but do not take part in the comparison for the set. A std::map is an associative container, that allows you