steps to reproduce

Write a loop, from 1 to 80000, each time add a random int to the max heap.

In theory it takes very little time(NlogN, N=80000, <1sec ), but the program does take a long time.

I'v also tested the BinaryHeap in https://github.com/SolutionsDesign/Algorithmia, it performs well, so it is probably due to the bad algorithm.

Given an array A of random integers and an integer k, find and return the kth largest element in the array.
Try to do this question in less than O(nlogn) time.
Input Format :

Line 1 : An integer N i.e. size of the array
Line 2 : N integers which are elements of the array, separated by spaces
Line 3 : An integer k

Output Format :

kth largest element

Input Constraints :
1 <= N, Ai,

I'm 100% sure I accidentally implemented this wrong for two children nodes — should fix. Algorithm should be something like:

find node to delete
  if has two children
  _node := max in left subtree || min in right subtree
  swap values
  delete _node

https://github.com/Divyanshnigam/PEPCO/blob/master/Binary%20Search%20Tree/Largest_BST.cpp