Switch to using heapq (#38)

The docstring of `SearchNode.__lt__` says you're using "heapq".

This patch actually makes it so ;-) and also improves efficiency.

Author: smurfix

astar/__init__.py

@@ -5,7 +5,7 @@
 from typing import Callable, Dict, Iterable, Union, TypeVar, Generic
 from math import inf as infinity
 from operator import attrgetter
-import sortedcontainers  # type: ignore
+import heapq
 
 # introduce generic type
 T = TypeVar("T")
@@ -48,23 +48,29 @@ def __missing__(self, k) -> SearchNode[T]:
 
 class OpenSet(Generic[SNType]):
     def __init__(self) -> None:
-        self.sortedlist = sortedcontainers.SortedList(key=attrgetter("fscore"))
+        self.heap: list[SNType] = []
 
     def push(self, item: SNType) -> None:
         item.in_openset = True
-        self.sortedlist.add(item)
+        heapq.heappush(self.heap, item)
 
     def pop(self) -> SNType:
-        item = self.sortedlist.pop(0)
+        item = heapq.heappop(self.heap)
         item.in_openset = False
         return item
 
     def remove(self, item: SNType) -> None:
-        self.sortedlist.remove(item)
+        idx = self.heap.index(item)
         item.in_openset = False
+        item = self.heap.pop()
+        if idx < len(self.heap):
+            self.heap[idx] = item
+            # Fix heap invariants
+            heapq._siftup(self.heap, idx)
+            heapq._siftdown(self.heap, 0, idx)
 
     def __len__(self) -> int:
-        return len(self.sortedlist)
+        return len(self.heap)
 
 
 ################################################################################*

pyproject.toml

@@ -19,7 +19,6 @@ packages = [
 
 [tool.poetry.dependencies]
 python = ">=3.8,<4.0.0"
-sortedcontainers = ">=2.4.0"
 
 [tool.poetry.dev-dependencies]
 black = ">=23.3.0"