Update of /cvsroot/rails/18xx/rails/game
In directory sfp-cvsdas-1.v30.ch3.sourceforge.com:/tmp/cvs-serv14471/rails/game
Modified Files:
MapManager.java
Log Message:
Added getHexDistance() to calculate the "as a crow with passport flies" distance for 1835.
Index: MapManager.java
===================================================================
RCS file: /cvsroot/rails/18xx/rails/game/MapManager.java,v
retrieving revision 1.15
retrieving revision 1.16
diff -C2 -d -r1.15 -r1.16
*** MapManager.java 8 Feb 2010 21:20:39 -0000 1.15
--- MapManager.java 9 Feb 2010 20:00:40 -0000 1.16
***************
*** 38,42 ****
protected static Logger log =
Logger.getLogger(MapManager.class.getPackage().getName());
!
public MapManager() {
}
--- 38,42 ----
protected static Logger log =
Logger.getLogger(MapManager.class.getPackage().getName());
!
public MapManager() {
}
***************
*** 214,217 ****
--- 214,269 ----
}
+ /**
+ * Calculate the distance between two hexes as in 1835,
+ * i.e. as "the crow without a passport flies".
+ * @param hex1
+ * @param hex2
+ * @return
+ */
+ public int getHexDistance (MapHex hex1, MapHex hex2) {
+ Map<MapHex, Integer> passed = new HashMap<MapHex, Integer>();
+ return calculateHexDistance (hex1, hex2, 1, passed);
+ }
+
+ /** Helper method to calculate the distance between two hexes.
+ * Called recursively. */
+ private int calculateHexDistance (MapHex hex1, MapHex hex2, int depth,
+ Map<MapHex, Integer> passed) {
+
+ /* Map to sort the neighbours (roughly) into decreasing distance */
+ SortedMap<Integer, MapHex> neighbours = new TreeMap<Integer, MapHex>();
+
+ for (MapHex hex3 : hex1.getNeighbors()) {
+
+ if (hex3 == null) continue;
+
+ // Are we finished?
+ if (hex3 == hex2) {
+ return 1;
+ }
+
+ if (passed.containsKey(hex3) && passed.get(hex3) < depth - 1) {
+ // Backtrack
+ return -1;
+ }
+ // Sort neighbours on decreasing (rough) distance
+ int distance = Math.abs(hex2.getX() - hex3.getX())
+ + Math.abs(hex2.getY() - hex3.getY());
+ neighbours.put(distance, hex3);
+ }
+ passed.put (hex1, depth);
+ for (MapHex neighbour : neighbours.values()) {
+ if (passed.containsKey(neighbour)) continue;
+ int result = calculateHexDistance (neighbour, hex2, depth+1, passed);
+ if (result < 0) {
+ return 0; // Continue backtracking
+ } else if (result > 0) {
+ return result + 1;
+ }
+ // Continue loop if result == 0
+ }
+ // Should never get here
+ return 0;
+ }
}
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