优先级队列实现为最大堆。最初，它有 5 个元素。堆的层序遍历是：10, 8, 5, 3, 2。两个新元素1和7按这个顺序插入到堆中。元素插入后堆的层序遍历为：
(一) 10, 8, 7, 3, 2, 1, 5
(B) 10, 8, 7, 2, 3, 1, 5
(C) 10, 8, 7, 1, 2, 3, 5
(D) 10, 8, 7, 5, 3, 2, 1答案：(一)
解释：
Initially heap has 10, 8, 5, 3, 2
10
/ \
8 5
/ \
3 2
After insertion of 1
10
/ \
8 5
/ \ /
3 2 1
No need to heapify as 5 is greater than 1.
After insertion of 7
10
/ \
8 5
/ \ / \
3 2 1 7
Heapify 5 as 7 is greater than 5
10
/ \
8 7
/ \ / \
3 2 1 5
No need to heapify any further as 10 is
greater than 7 这个问题的测验