# Heap

Published on Wednesday, 18 July 2018

### What is Heap?

Heap is a binary tree representation.

Intro to Algo by C.L.R.S (page 159) can be applied part that I had trouble is the derivation.

• n element heap has height of `lg n`
• at most `n / (2^(h+1))` nodes of any height h

(i draw some examples which worked)

changed the limit to get better approx for `O()`

Leaf nodes are (in 0 based index),

``````n/2, n/2+1, n/2+2, n/2+3 ... ... ... n
``````

Question: Why does the book (CLRS) use 1 based index where programming languages are based on 0? A common standard among books for pseudocode.

### delete element operation

The idea is similar to `Extract-Min`. We replace `i` with `A[size-1]` then, we heapify. Applied that this idea on to solve hackkerrank qHeap.

Deriving the tighter bound I mean in some pages in book.

A problem that uses counting sort but probably hard (Codeforces Round #182 (Div. 1)), http://codeforces.com/contest/301/problem/D

### Min-Max Fine Heaps

heap, introduced by Carlsson[2], using bit in each node to indicate its larger child, to improve the performance of Min-Max Heap. We call it Min-Max Fine Heap. Also a technique similar to the one used by Gonnet and Munro[5] for traditional heaps will be employed for better performance. In the next sections we shall present the structure of the heap, algorithm for carrying out the standard operations on deq

Hash table runtime complexity (insert, search and delete) https://stackoverflow.com/questions/9214353/hash-table-runtime-complexity-insert-search-and-delete

Show that second smallest of n elements can be found with `n + logn -2` in worst case..

Heap during finding the minimum??? https://www.careercup.com/question?id=354885

** on my heap sort or heap implementation verification ** https://www.hackerrank.com/contests/hw1/challenges/heap-sort https://www.hackerrank.com/challenges/qheap1/problem

checking if anybody got accepted with dijkstra short reach github.com hackerrank dijkstrashortreach cpp implementation

### References

1. Page# 159 the book, Introduction to Algorithm - C.L.R.S
2. Stony Brook Univ. Lecture - Dijkstraâ€™s SSSP & Fibonacci Heaps