duplicate key value pairs
data-structures, java
Solution
You can simulate multiple key-value (KV) pairs by saving a list of values for each in a map. This is a standard implementation approach for "multivalue" maps.
So, if the key is a `Character` object and the value is `Boolean`, you can do
Map<Character, List<Boolean>> multimap = new HashMap<Character, List<Boolean>>();
and every time you want to add a new value to an existing KV pair in the map just call
multimap.get(key).add(value);
where `key` is the Character and `value` its corresponding `Boolean` value.
The `Guava` library by `Google` (free download) has a Multimap interface implemented in various ways, so essentially you can instantiate a `MultiMap<Character, Boolean>` map and use it accordingly. Similarly, you can get the `Apache Commons Collections` library and use its `MultiValueMap` class. You may also want to check the answers to a similar StackOverflow question, or another one.
If you only want to store one of each value per key, then a `Set` should be used in the place of the `List`.
Problem
Is there a native data structure in java that accepts key value pairs and allows duplicates? I am creating a checklist of characters in a string but some characters occur more than once. ex ``` j -> false a -> false v -> false a -> false ```