Find The Closest Answer in HashMap

Question

I want to search for a key in a hashmap and find the nearest one to that key!

    HashMap map = new HashMap();
         


        

Answer 1

Using a NavigableMap like a TreeMap

long key = 
NavigableMap map = new TreeMap();

Long before = map.floorKey(key);
Long after = map.ceilingKey(key);
if (before == null) return after;
if (after == null) return before;
return (key - before < after - key 
       || after - key < 0) 
       && key - before > 0 ? before : after;