heapq模块常见操作python代码

以下是 `heapq` 模块中常见的操作和对应的 Python 代码示例：

1. 将列表转化为堆：`heapq.heapify(lst)`

import heapq

lst = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5]
heapq.heapify(lst)
print(lst)  # 输出 [1, 1, 2, 3, 3, 9, 4, 6, 5, 5, 5]

2. 从堆中弹出最小的元素：`heapq.heappop(heap)`

import heapq

heap = [1, 3, 2, 6, 4, 8, 5, 7, 9]
min_element = heapq.heappop(heap)
print(min_element)  # 输出 1

3. 将元素加入堆中：`heapq.heappush(heap, item)`

import heapq

heap = [1, 3, 2, 6, 4, 8, 5, 7, 9]
heapq.heappush(heap, 0)
print(heap)  # 输出 [0, 1, 2, 6, 3, 8, 5, 7, 9, 4]

4. 获取堆中最小的元素，但不弹出：`heapq.nsmallest(n, heap)`

import heapq

heap = [1, 3, 2, 6, 4, 8, 5, 7, 9]
smallest_3 = heapq.nsmallest(3, heap)
print(smallest_3)  # 输出 [1, 2, 3]

5. 获取堆中最大的元素，但不弹出：`heapq.nlargest(n, heap)`

import heapq

heap = [1, 3, 2, 6, 4, 8, 5, 7, 9]
largest_3 = heapq.nlargest(3, heap)
print(largest_3)  # 输出 [9, 8, 7]