Added functionality to find the trail the algorithm took

src/main/java/mattrixwv/ProjectEuler/Problems/Problem18.java

@@ -43,6 +43,7 @@ package mattrixwv.ProjectEuler.Problems;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Iterator;
 
 import mattrixwv.ProjectEuler.Unsolved;
 
@@ -55,7 +56,6 @@ public class Problem18 extends Problem{
 		public int yLocation;
 		public int total;
 		//Used originally for debugging so I could trace the path backwards
-		@SuppressWarnings("unused")
 		public boolean fromRight;
 		location(int x, int y, int t, boolean r){
 			xLocation = x;
@@ -213,8 +213,58 @@ public class Problem18 extends Problem{
 		}
 
 		StringBuilder results = new StringBuilder();
-		//TODO: Implement this
-		results.append("This has not yet been implemented");
+		//Save the trail the algorithm took
+		ArrayList<location> trail = new ArrayList<location>();
+		trail.add(foundPoints.get(foundPoints.size() - 1));
+		boolean top = false;
+		while(!top){
+			boolean found = false;
+			int loc = foundPoints.size() - 1;
+			location toAdd = null;
+			while(!found){
+				if(loc < 0){
+					results.append("Error: Location < 0\n");
+					System.exit(1);
+				}
+				Iterator<location> it = foundPoints.iterator();
+				location tempLoc = null;
+				for(int cnt = 0;cnt < loc;++cnt){
+					tempLoc = it.next();
+				}
+				if(trail.get(0).fromRight){
+					if((tempLoc.xLocation == trail.get(0).xLocation) && (tempLoc.yLocation == (trail.get(0).yLocation - 1))){
+						found = true;
+						toAdd = tempLoc;
+					}
+					else{
+						--loc;
+					}
+				}
+				else{
+					if((tempLoc.xLocation == (trail.get(0).xLocation - 1)) && (tempLoc.yLocation == (trail.get(0).yLocation - 1))){
+						found = true;
+						toAdd = tempLoc;
+					}
+					else{
+						--loc;
+					}
+				}
+			}
+
+			trail.add(0, toAdd);
+
+			if(trail.get(0).yLocation == 0){
+				top = true;
+			}
+		}
+
+		for(location loc : trail){
+			results.append(list.get(loc.yLocation).get(loc.xLocation));
+			if(loc.yLocation < (list.size() - 1)){
+				results.append("->");
+			}
+		}
+
 		return results.toString();
 	}
 	//Returns the total that was asked for