refactor(game): add Map.closest and improve flag assignment logic

- Introduced `Map.closest` to encapsulate nearest‑position search and replaced duplicated distance loops in flag targeting.
- Updated flag assignment to consider enemy players carrying flags and to use the new helper for both ally and enemy flag selection.
- Cleaned up unused imports and renamed `mypolicy` to `mypolicy.py` for clarity.
- Adjusted frontend `game_config.json` to use new team identifiers, increase players to 3, raise flag count to 9, and enable random flag placement.

CTF/backend/mypolicy.py

@@ -1,16 +1,15 @@
 import asyncio
-import random
 from lib.game_engine import GameMap, run_game_server
 import threading
 import collections
 
-# 1. Initialize the global world model
 world = GameMap(show_gap_in_msec=10.0)
 lock = threading.Lock()
 last_updated_time = -1
 update_threshold = 10
 player_to_flag_assign = {}
 my_side_is_left = None
+
 class Map:
     def __init__(self):
         self.width  = world.width
@@ -84,11 +83,8 @@ class Map:
                     dist[v] = dist[u] + 1
                     prev[v] = u
                     queue.append(v)
-
-        # ---- 若不可达，返回空字符串 ----
         if dist[dst_idx] == float('inf'):
             return ""
-        # ---- 重建路径（逆序） ----
         path = []
         cur = dst_idx
         while cur is not None:
@@ -125,7 +121,15 @@ class Map:
         if dist[dst_idx] == float('inf'):
             return -1
         return dist[dst_idx]
-
+    def closest(self, posx_start, posy_start, positions):
+        closest_pos = None
+        min_length = float('inf')
+        for pos in positions:
+            temp = self.length(posx_start, posy_start, pos[0], pos[1])
+            if temp != -1 and temp < min_length:
+                min_length = temp
+                closest_pos = pos
+        return closest_pos
 myMap = Map()
 def start_game(req):
     global player_to_flag_assign,my_side_is_left
@@ -141,14 +145,16 @@ def plan_next_actions(req):
     global player_to_flag_assign,myMap,my_side_is_left
 
     my_players = world.list_players(mine=True, inPrison=False, hasFlag=None)
-    opponents = world.list_players(mine=False, inPrison=False, hasFlag=None)
+    enemy_players_flags = world.list_players(mine=False, inPrison=False, hasFlag=True)
     enemy_flags = world.list_flags(mine=False, canPickup=True)
-    my_flags = world.list_flags(mine=True, canPickup=True)
     my_targets = list(world.list_targets(mine=True))
     active_player_names = {p["name"] for p in my_players if not p["hasFlag"]}
     flags_list = []
-    for flags in my_flags:
+    regard_list = []
+    for flags in enemy_flags:
         flags_list.append((flags["posX"],flags["posY"]))
+    for p in enemy_players_flags:
+        regard_list.append((p["posX"],p["posY"]))
     player_to_flag_assign = {
         name: pos for name, pos in player_to_flag_assign.items()
         if name in active_player_names
@@ -160,14 +166,7 @@ def plan_next_actions(req):
             if p["name"] in player_to_flag_assign and player_to_flag_assign[p["name"]] in flags_list:
                 flags_list.remove(player_to_flag_assign[p["name"]])
                 continue
-            closest_flag = None
-            min_length = float('inf')
-            for f in flags_list:
-                temp = myMap.length(p["posX"],p["posY"],f[0],f[1])
-                if temp != -1 and temp < min_length:
-                    min_length = temp
-                    closest_flag = f
-            f = closest_flag
+            f = myMap.closest(p["posX"],p["posY"],flags_list)
             if f is not None:
                 player_to_flag_assign[p["name"]] = (f[0],f[1])
                 print(f[0], f[1])
@@ -177,16 +176,16 @@ def plan_next_actions(req):
     player_moves = {}
 
     for p in my_players:
-        curr_pos = (p["posX"], p["posY"])
-
-        # Determine Target: Either the assigned flag or the home target
         if p["hasFlag"]:
             dest = my_targets[0]
         elif p["name"] in player_to_flag_assign:
             dest = player_to_flag_assign[p["name"]]
         else:
-            continue
-
+            f = myMap.closest(p["posX"],p["posY"],regard_list)
+            if f is not None:
+                dest = (f[0],f[1])
+            else:
+                continue
         player_moves[p["name"]] = myMap.guideance(p["posX"],p["posY"],dest[0],dest[1])
 
     return player_moves