diff --git a/AgRobotSwarmForSearch/search.py b/AgRobotSwarmForSearch/search.py
index 276dee913c9078d2b475e0297822cf6d692c4908..eafe6fc790fbba8655014aedd78ac9523e3796ec 100644
--- a/AgRobotSwarmForSearch/search.py
+++ b/AgRobotSwarmForSearch/search.py
@@ -119,6 +119,7 @@ class Simulation:
         return [n for n in self.sim_graph.neighbors(node)]
 
     def expand(self) -> tuple[bool, str]:
+        ### this has grown very badly ### Please rewrite
         self.current_node = self.chosen
         self.mark_expansion_step(self.current_node)
         self.expansion_step += 1
@@ -130,17 +131,9 @@ class Simulation:
         children = sorted(self.generate_child_nodes(self.current_node))
         for child in children:
             # check if child already in explored or frontier
+
             if child in self.explored_set:
                 continue
-            if child in self.frontier_set:
-                continue
-
-            # create entry in frontier
-            self.frontier.append((self.current_node, child))
-            self.frontier_history["item"].append((self.current_node, child))
-            self.frontier_history_unsorted["item"].append((self.current_node, child))
-            self.frontier_history["avail"].append(True)
-            self.frontier_history_unsorted["step"].append("")
 
             # calculate the path cost g(n) and heuristic values h(n)
             cost_to_node = self.get_cost_of_current_path()
@@ -148,28 +141,82 @@ class Simulation:
                 (self.current_node, child)
             ]["dist"]
             path_cost = cost_to_node + cost_from_node_to_child
-            self.frontier_history["path_cost"].append(path_cost)
-            self.frontier_history_unsorted["path_cost"].append(path_cost)
             heuristic = self.get_heuristic(node=child)
-            self.frontier_history["heuristic"].append(heuristic)
-            self.frontier_history_unsorted["heuristic"].append(heuristic)
-
-            # calculate f(n)
-            if self.search_method == "UCS":
-                # f(n) = g(n)
-                self.frontier_history["cost"].append(path_cost)
-                self.frontier_history_unsorted["cost"].append(path_cost)
-            elif self.search_method == "GreedyBestFirst":
-                # f(n) = h(n)
-                self.frontier_history["cost"].append(heuristic)
-                self.frontier_history_unsorted["cost"].append(heuristic)
-            elif self.search_method == "A*":
-                # f(n) = g(n) + h(n)
-                self.frontier_history["cost"].append(path_cost + heuristic)
-                self.frontier_history_unsorted["cost"].append(path_cost + heuristic)
+
+            # check if cheaper version is available if already in frontier
+            if child in self.frontier_set:
+                # when using BFS or DFS continue without checking
+                if self.search_method == "DFS" or self.search_method == "BFS":
+                    continue
+                hist_idx = next(
+                    i
+                    for i, (*_, v) in enumerate(self.frontier_history["item"])
+                    if v == child
+                )
+                hist_unsorted_idx = next(
+                    i
+                    for i, (*_, v) in enumerate(self.frontier_history_unsorted["item"])
+                    if v == child
+                )
+
+                if self.search_method == "UCS":
+                    if self.frontier_history["cost"][hist_idx] <= path_cost:
+                        continue
+                if self.search_method == "GreedyBestFirst":
+                    if self.frontier_history["cost"][hist_idx] <= heuristic:
+                        continue
+                if self.search_method == "A*":
+                    if self.frontier_history["cost"][hist_idx] <= path_cost + heuristic:
+                        continue
+
+                # update entry in frontier_hist
+                self.frontier_history["item"][hist_idx] = (self.current_node, child)
+                self.frontier_history_unsorted["item"][hist_unsorted_idx] = (
+                    self.current_node,
+                    child,
+                )
+                self.frontier_history["avail"][hist_idx] = True
+                self.frontier_history_unsorted["step"][hist_unsorted_idx] = ""
+
+                self.frontier_history["path_cost"][hist_idx] = path_cost
+                self.frontier_history_unsorted["path_cost"][
+                    hist_unsorted_idx
+                ] = path_cost
+                self.frontier_history["heuristic"][hist_idx] = heuristic
+                self.frontier_history_unsorted["heuristic"][
+                    hist_unsorted_idx
+                ] = heuristic
             else:
-                self.frontier_history["cost"].append(path_cost)
-                self.frontier_history_unsorted["cost"].append(path_cost)
+                # create entry in frontier
+                self.frontier.append((self.current_node, child))
+                self.frontier_history["item"].append((self.current_node, child))
+                self.frontier_history_unsorted["item"].append(
+                    (self.current_node, child)
+                )
+                self.frontier_history["avail"].append(True)
+                self.frontier_history_unsorted["step"].append("")
+
+                self.frontier_history["path_cost"].append(path_cost)
+                self.frontier_history_unsorted["path_cost"].append(path_cost)
+                self.frontier_history["heuristic"].append(heuristic)
+                self.frontier_history_unsorted["heuristic"].append(heuristic)
+
+                # calculate f(n)
+                if self.search_method == "UCS":
+                    # f(n) = g(n)
+                    self.frontier_history["cost"].append(path_cost)
+                    self.frontier_history_unsorted["cost"].append(path_cost)
+                elif self.search_method == "GreedyBestFirst":
+                    # f(n) = h(n)
+                    self.frontier_history["cost"].append(heuristic)
+                    self.frontier_history_unsorted["cost"].append(heuristic)
+                elif self.search_method == "A*":
+                    # f(n) = g(n) + h(n)
+                    self.frontier_history["cost"].append(path_cost + heuristic)
+                    self.frontier_history_unsorted["cost"].append(path_cost + heuristic)
+                else:
+                    self.frontier_history["cost"].append(path_cost)
+                    self.frontier_history_unsorted["cost"].append(path_cost)
 
             if self.search_method == "DFS" or self.search_method == "BFS":
                 # # test every child added to frontier for goal