How can building a heap be O(n) time complexity?

Question

Can someone help explain how can building a heap be O(n) complexity?

Inserting an item into a heap is O(log n), and the insert is repeated n/2 times (t

Answer 1

think you're making a mistake. Take a look at this: http://golang.org/pkg/container/heap/ Building a heap isn'y O(n). However, inserting is O(lg(n). I'm assuming initialization is O(n) if you set a heap size b/c the heap needs to allocate space and set up the data structure. If you have n items to put into the heap then yes, each insert is lg(n) and there are n items, so you get n*lg(n) as u stated