Dynamic 2-D map for A*search pathfinding problem

Question

The Problem is a Dynamic map (the user can change size of the map) that has obstacles(obstacle location determined by the user also) and the tile could only move to adjacent tiles(only 4 moves or less), Can anyone solve that in Java? (without visualization only sample code).

Answer 1

basically im trying to match the value of one Map with the key of another. my thinking is that this requires me to loop through the first Map and for each value through the second Map and match up the key to it. heres my code so far:
private static Map equiJoin(Map relation1, Map relation2) // The 2 maps
Map resultRelation = new TreeMap();
Iterator keys1Iterator = relation1.keySet().iterator();
Iterator values1Iterator = relation1.values().iterator();
while (keys1Iterator.hasNext() ) // Loop through relation1
String primaryKey1 = (String) keys1Iterator.next();
String foreignKey1 = (String) values1Iterator.next();
List list = new ArrayList();
Iterator keys2Iterator = relation2.keySet().iterator();
Iterator values2Iterator = relation2.values().iterator();
while (keys2Iterator.hasNext() ) // Loop through relation2
String primaryKey2 = (String) keys2Iterator.next();
String foreignKey2 = (String) values2Iterator.next();
if(primaryKey2.equals(foreignKey1))
list.add(foreignKey1);
list.add(foreignKey2);
resultRelation.put(primaryKey1, list);
return resultRelation;
im trying to come up with ways to make this faster, perhaps by turing the second while loop/linear search into a binary search. i do indeed think using the get(key) more would increase the speed but im still thinking about ways to implement that in the above code, the problem being that i dont know what key im looking for until i loop through it (if u know what i mean) =)
many thanks.