SI_InteligentnyWozekWidlowy/util/Pathfinder.py
Aleksander Szamałek 59676e176a Pathfinder
2022-04-08 00:43:25 +02:00

37 lines
1.1 KiB
Python

from typing import Optional, Dict, Tuple
from util.PathDefinitions import WeightedGraph, Location
from util.PriorityQueue import PriorityQueue
def heuristic(a: Tuple[int, int], b: Tuple[int, int]) -> float:
(x1, y1) = a
(x2, y2) = b
return abs(x1 - x2) + abs(y1 - y2)
def a_star_search(graph: WeightedGraph, start: Tuple[int, int], goal: Tuple[int, int]):
frontier = PriorityQueue()
frontier.put(start, 0)
came_from: Dict[Location, Optional[Location]] = {}
cost_so_far: Dict[Location, float] = {}
came_from[start] = None
cost_so_far[start] = 0
while not frontier.empty():
current: Location = frontier.get()
if current == goal:
break
for next in graph.neighbors(current):
new_cost = cost_so_far[current] + graph.cost(current, next)
if next not in cost_so_far or new_cost < cost_so_far[next]:
cost_so_far[next] = new_cost
priority = new_cost + heuristic(next, goal)
frontier.put(next, priority)
came_from[next] = current
return came_from, cost_so_far.keys()