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