# 構建小頂堆跳轉
def sift(li, low, higt):
tmp = li[low]
i = low
j = 2 * i + 1
while j <= higt: # 情況2：i已經是最后一層
if j + 1 <= higt and li[j + 1] < li[j]: # 右孩子存在並且小於左孩子
j += 1
if tmp > li[j]:
li[i] = li[j]
i = j
j = 2 * i + 1
else:
break # 情況1：j位置比tmp小
li[i] = tmp
def top_k(li, k):
heap = li[0:k]
# 建堆
for i in range(k // 2 - 1, -1, -1):
sift(heap, i, k - 1)
for i in range(k, len(li)):
if li[i] > heap[0]:
heap[0] = li[i]
sift(heap, 0, k - 1)
# 挨個輸出
for i in range(k - 1, -1, -1):
heap[0], heap[i] = heap[i], heap[0]
sift(heap, 0, i - 1)
return heap
li = [0, 8, 6, 2, 4, 9, 1, 4, 6]
print(top_k(li, 3))
