mirror of
https://github.com/zhm-real/PathPlanning.git
synced 2026-08-30 00:50:46 +08:00
zhm-real
154 lines
4.0 KiB
Python
154 lines
4.0 KiB
Python
import collections
|
|
import heapq
|
|
import itertools
|
|
|
|
class QueueFIFO:
|
|
"""
|
|
Class: QueueFIFO
|
|
Description: QueueFIFO is designed for First-in-First-out rule.
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.queue = collections.deque()
|
|
|
|
def empty(self):
|
|
return len(self.queue) == 0
|
|
|
|
def put(self, node):
|
|
self.queue.append(node) # enter from back
|
|
|
|
def get(self):
|
|
return self.queue.popleft() # leave from front
|
|
|
|
|
|
class QueueLIFO:
|
|
"""
|
|
Class: QueueLIFO
|
|
Description: QueueLIFO is designed for Last-in-First-out rule.
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.queue = collections.deque()
|
|
|
|
def empty(self):
|
|
return len(self.queue) == 0
|
|
|
|
def put(self, node):
|
|
self.queue.append(node) # enter from back
|
|
|
|
def get(self):
|
|
return self.queue.pop() # leave from back
|
|
|
|
|
|
class QueuePrior:
|
|
"""
|
|
Class: QueuePrior
|
|
Description: QueuePrior reorders elements using value [priority]
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.queue = []
|
|
|
|
def empty(self):
|
|
return len(self.queue) == 0
|
|
|
|
def put(self, item, priority):
|
|
heapq.heappush(self.queue, (priority, item)) # reorder x using priority
|
|
|
|
def get(self):
|
|
return heapq.heappop(self.queue)[1] # pop out the smallest item
|
|
|
|
def enumerate(self):
|
|
return self.queue
|
|
|
|
def check_remove(self, item):
|
|
for (p, x) in self.queue:
|
|
if item == x:
|
|
self.queue.remove((p, x))
|
|
|
|
def top_key(self):
|
|
return self.queue[0][0]
|
|
|
|
class MinheapPQ:
|
|
"""
|
|
A priority queue based on min heap, which takes O(logn) on element removal
|
|
https://docs.python.org/3/library/heapq.html#priority-queue-implementation-notes
|
|
"""
|
|
def __init__(self):
|
|
self.pq = [] # lis of the entries arranged in a heap
|
|
self.nodes = set()
|
|
self.entry_finder = {} # mapping of the item entries
|
|
self.counter = itertools.count() # unique sequence count
|
|
self.REMOVED = '<removed-item>'
|
|
|
|
def put(self, item, priority):
|
|
'''add a new task or update the priority of an existing item'''
|
|
if item in self.entry_finder:
|
|
self.check_remove(item)
|
|
count = next(self.counter)
|
|
entry = [priority, count, item]
|
|
self.entry_finder[item] = entry
|
|
heapq.heappush(self.pq, entry)
|
|
self.nodes.add(item)
|
|
|
|
def check_remove(self, item):
|
|
if item not in self.entry_finder:
|
|
return
|
|
entry = self.entry_finder.pop(item)
|
|
entry[-1] = self.REMOVED
|
|
self.nodes.remove(item)
|
|
|
|
def get(self):
|
|
"""Remove and return the lowest priority task. Raise KeyError if empty."""
|
|
while self.pq:
|
|
priority, count, item = heapq.heappop(self.pq)
|
|
if item is not self.REMOVED:
|
|
del self.entry_finder[item]
|
|
self.nodes.remove(item)
|
|
return item
|
|
raise KeyError('pop from an empty priority queue')
|
|
|
|
def top_key(self):
|
|
return self.pq[0][0]
|
|
|
|
def enumerate(self):
|
|
return self.pq
|
|
|
|
def allnodes(self):
|
|
return self.nodes
|
|
|
|
# class QueuePrior:
|
|
# """
|
|
# Class: QueuePrior
|
|
# Description: QueuePrior reorders elements using value [priority]
|
|
# """
|
|
|
|
# def __init__(self):
|
|
# self.queue = []
|
|
|
|
# def empty(self):
|
|
# return len(self.queue) == 0
|
|
|
|
# def put(self, item, priority):
|
|
# count = 0
|
|
# for (p, x) in self.queue:
|
|
# if x == item:
|
|
# self.queue[count] = (priority, item)
|
|
# break
|
|
# count += 1
|
|
# if count == len(self.queue):
|
|
# heapq.heappush(self.queue, (priority, item)) # reorder x using priority
|
|
|
|
# def get(self):
|
|
# return heapq.heappop(self.queue)[1] # pop out the smallest item
|
|
|
|
# def enumerate(self):
|
|
# return self.queue
|
|
|
|
# def check_remove(self, item):
|
|
# for (p, x) in self.queue:
|
|
# if item == x:
|
|
# self.queue.remove((p, x))
|
|
|
|
# def top_key(self):
|
|
# return self.queue[0][0] |