Python笔记精讲之数据结构

最小堆

代码：

>>> import heapq
>>> import random
>>> data=list(range(10))
>>> random.shuffle(data)   #随机打乱
>>> data
[9, 0, 4, 2, 7, 8, 5, 3, 6, 1]
>>> heap=[]
>>> for n in data:
...     heapq.heap
heapq.heapify(      heapq.heappush(     heapq.heapreplace(
heapq.heappop(      heapq.heappushpop(  
...     heapq.heappush(heap,n)   #创建堆
... 
>>> heap
[0, 1, 4, 3, 2, 8, 5, 9, 6, 7]
>>> heapq.heappush(heap,0.5)
>>> heap
[0, 0.5, 4, 3, 1, 8, 5, 9, 6, 7, 2]
>>> heapq.heappop(heap)     #弹出最小的元素堆会自动重建
0
>>> heapq.heappop(heap)
0.5
>>> myheap=[1,2,3,5,7,8,9,4,10,333]
>>> heapq.heapify(myheap)      #将列表转化为堆
>>> myheap
[1, 2, 3, 4, 7, 8, 9, 5, 10, 333]
>>> heapq.heapreplace(myheap,6)  #替换堆中的元素值，自动重新构建堆
1    #返回被替换的最小值
>>> myheap
[2, 4, 3, 5, 7, 8, 9, 6, 10, 333]
>>> heapq.nlargest(3,myheap)   #返回前3个最大的元素
[333, 10, 9]
>>> heapq.nsmallest(3,myheap)   #返回前3个最小的元素
[2, 3, 4]

队列

>>> import queue

>>> q=queue.
queue.Empty(          queue.Queue(          queue.heappush(
queue.Full(           queue.SimpleQueue(    queue.threading
queue.LifoQueue(      queue.deque(          queue.time(
queue.PriorityQueue(  queue.heappop(        
>>> q=queue.Queue()
>>> q.put(0)
>>> q.put(3)
>>> q.put(2)
>>> q.queue
deque([0, 3, 2])
>>> q.get()
0
>>> q.get()
3

“后进先出”队列

>>> lifo=queue.LifoQueue(5)
>>> lifo.put(6)
>>> lifo.put(2)
>>> lifo.put(7)
>>> lifo.put(5)
>>> 
>>> lifo.get()
5
>>> lifo.get()
7

优先级队列

>>> pq=queue.PriorityQueue(5)
>>> pq.put(3)
>>> pq.put(5)
>>> pq.put(1)
>>> pq.put(8)
>>> pq.queue
[1, 5, 3, 8]
>>> pq.get()
1
>>> pq.get()
3
>>> pq.get()
5
>>> pq.get()
8