Courses βeta
Data Structures

## Time Complexity of building a heap

Consider the following algorithm for building a Heap of an input array A.

BUILD-HEAP(A)

heapsize := size(A);

for i := floor(heapsize/2) downto 1

do HEAPIFY(A, i);

end for
END



What is the worst case time complexity of the above algo?
Although the worst case complexity looks like O(nLogn), upper bound of time complexity is O(n). See following links for the proof of time complexity.

http://www.cse.iitk.ac.in/users/sbaswana/Courses/ESO211/heap.pdf/
http://www.cs.sfu.ca/CourseCentral/307/petra/2009/SLN_2.pdf

### Feedback

For any feedback,email us at feedback@geeksforgeeks.org

### Report a Bug

For any report or bug,email us at support@geeksforgeeks.org