Кучи и очереди с приоритетом

a = [1, 4, 3, 9, 7, 8, 5]
valid = True
for parent in range(len(a) // 2):
    left = 2 * parent + 1
    right = left + 1
    if left < len(a) and a[parent] > a[left]:
        valid = False
    if right < len(a) and a[parent] > a[right]:
        valid = False
print(valid)

i = 3
left = 2 * i + 1
right = 2 * i + 2
print(left, right)

i = 8
parent = (i - 1) // 2
print(parent)

a = [3, 5, 4, 9, 7, 8]
a.append(2)
i = len(a) - 1
while i > 0:
    p = (i - 1) // 2
    if a[p] <= a[i]:
        break
    a[p], a[i] = a[i], a[p]
    i = p
print(a)

a = [4, 9, 7, 3, 8, 6]
i = 0
left, right = 1, 2

for i in range(n // 2 - 1, -1, -1):
    sift_down(a, i)

import heapq
heap = []
for priority, order, name in [(2,0,'A'), (1,1,'B'), (1,2,'C'), (3,3,'D')]:
    heapq.heappush(heap, (priority, order, name))
out = []
while heap:
    out.append(heapq.heappop(heap)[2])
print(out)

while heap:
    dist, v = heapq.heappop(heap)
    if dist != best[v]:
        continue
    break

import heapq
values = [4, 9, 2]
heap = []
for x in values:
    heapq.heappush(heap, -x)
print(-heapq.heappop(heap))

import heapq
k = 3
heap = []
for x in [5, 1, 9, 3, 8, 7]:
    if len(heap) < k:
        heapq.heappush(heap, x)
    elif x > heap[0]:
        heapq.heapreplace(heap, x)
print(sorted(heap))

def keep_k_smallest(stream, k):
    heap = []
    for value in stream:
        if len(heap) < k:
            push_candidate(heap, value)
        elif value < largest_saved(heap):
            replace_largest(heap, value)
    return heap

# Нужно выбрать тип кучи для heap.

# heap содержит k наибольших элементов