restructure, slow security solution

asecbadge.py

@@ -0,0 +1,42 @@
+from collections import deque, defaultdict
+from intset import IntSet
+
+N, L, B = map(int, input().split())
+
+S, D = map(int, input().split())
+
+rooms = defaultdict(dict)
+
+ALL = IntSet(1, B + 1)
+NONE = IntSet()
+
+for i in range(L):
+    a, b, x, y = map(int, input().split())
+    rooms[a][b] = IntSet(x, y + 1)
+
+ranges = defaultdict(lambda: NONE)
+ranges[S] = ALL
+
+q = deque([S])
+
+while q:
+    if len(ranges[D]) == B:
+        break
+
+    curr = q.pop()
+
+    # if curr == D:
+    #     continue
+
+    for neighbor, r in rooms[curr].items():
+        old = ranges[neighbor]
+        new = ranges[neighbor] | ranges[curr] & r
+        if old != new:
+            # try:
+            #     q.remove(neighbor)
+            # except ValueError:
+            #     pass
+            q.append(neighbor)
+        ranges[neighbor] = new
+
+print(len(ranges[D]))