1. In a d-ary heap, up-heaps (e.g., insert, decrease-key if you track heap nodes as they move around) take time O (log_d n) and down-heaps (e.g., delete-min) take time O (d log_d n), where n is the number of nodes. The reason that down-heaps are more expensive is that we have to find the minimum child to promote, whereas up-heaps just compare ...I implemented a D-ary max heap backed by a vector for resizing. I would like to know any possible improvements in performance, design, and in the code in general. #pragma once #include <vector...The d-ary heap data structure is a generalization of a binary heap in which each node has d children instead of 2. This speeds up "push" or "decrease priority" operations ( O(log n / log d) ) with the tradeoff of slower "pop" or "increase priority" ( O(d log n / log d) ). d-ary heap O(log dV) O(d log dV) O((dV + E) log dV) Fibonacci heap O(1) amortized O(log V) O(E +V log V) Which is best depends on sparsityof graph: ratio E/V (average degree). Linked list vs. binary heap Dense graph: E = £(V2) Linked list is better: O(V2) Sparse graph: E = O(V) Binary heap is better: O(V log V) d-ary heap Best choice d ¼E/V ...I find d * i + 2 - d for the index of the first child, if items are numbered starting from 1. Here is the reasoning. Each row contains the children of the previous row. If n[r] are the number of items on row r, one must have n[r+1] = d * n[r], which proves that n[r] = d**r if the first row is numbered 0.The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2. [1] [2] [3] Thus, a binary heap is a 2-heap, and a ternary heap is a 3-heap. According to Tarjan [2] and Jensen et al., [4] d -ary heaps were invented by Donald B. Johnson in 1975. Sep 9, 2016 · 1 Answer. In a ternary heap, each node has up to three children. The heap is represented in the array in breadth-first order, with the root node at 0, and the children of node x at locations (x*3)+1, (x*3)+2, and (x*3)+3. The node at location x is at (x-1)/3. So, your array, [90,82,79,76,46,1,49,44,61,62], looks like this when displayed the ... Internally, the d-ary heap is represented as dynamically sized array (std::vector), that directly stores the values. The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used.Explanation: Although pairing heap is an efficient algorithm, it is worse than the Fibonacci heap. Also, pairing heap is faster than d-ary heap and binary heap. 13.Sep 3, 2012 · The d_ary_heap_indirect is designed to only allow priorities to increase. If in the update () and push_or_update () functions you change: preserve_heap_property_up (index); to. preserve_heap_property_up (index); preserve_heap_property_down (); it seems to allow increasing or decreasing the priorities while keeping the queue sorted. Binomial Heaps - Princeton University 5. (CLRS 6-2) Analysis of d-ary heaps A d-ary heap is like a binary heap, but instead of 2 children, nodes have d children. a. How would you represent a d-ary heap in a array? b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an e cient implementation of Extract-Max. Analyze its running time in terms of d and n. d. Internally, the d-ary heap is represented as dynamically sized array (std::vector), that directly stores the values. The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used.10. Instead of a binary heap, we could implement a d-ary heap, which uses d-ary tree. In such a tree, each node has between 0 and d children. As for the binary heap, we assume that a d-ary heap is a complete d-ary tree and can be stored in an array.5. (CLRS 6-2) Analysis of d-ary heaps A d-ary heap is like a binary heap, but instead of 2 children, nodes have d children. a. How would you represent a d-ary heap in a array? b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an e cient implementation of Extract-Max. Analyze its running time in terms of d and n. d.If so, I tend to think it is indeed tight. For a hint, this paper: The Analysis of Heapsort mentions that (in Abstract) The number of keys moved during 2 2 -ary heap-sort when sorting a random file of n n distinct elements is n lg n + O(n) n lg n + O ( n) in the worst case. It even further proves that (Notice that it is for the best case)Construction of a binary (or d-ary) heap out of a given array of elements may be performed in linear time using the classic Floyd algorithm, with the worst-case number of comparisons equal to 2N − 2s 2 (N) − e 2 (N) (for a binary heap), where s 2 (N) is the sum of all digits of the binary representation of N and e 2 (N) is the exponent of 2 ... D-ary heap. D-ary heap is a complete d-ary tree filled in left to right manner, in which holds, that every parent node has a higher (or equal value) than all of its descendands. Heap respecting this ordering is called max-heap, because the node with the maximal value is on the top of the tree. Analogously min-heap is a heap, in which every ...d-ary heap O(log dV) O(d log dV) O((dV + E) log dV) Fibonacci heap O(1) amortized O(log V) O(E +V log V) Which is best depends on sparsityof graph: ratio E/V (average degree). Linked list vs. binary heap Dense graph: E = £(V2) Linked list is better: O(V2) Sparse graph: E = O(V) Binary heap is better: O(V log V) d-ary heap Best choice d ¼E/V ...The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2. Here is the source code of the Java program to implement D-ary Heap. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.K-ary heap has better memory cache behaviour than a binary heap which allows them to run more quickly in practice, although it has a larger worst case running time of both extractMin () and delete () operation (both being O (k log k n) ). Implementation:•Can think of heap as a completebinary tree that maintains the heap property: –Heap Property: Every parent is better-than[less-than if min-heap, or greater-than if max-heap] bothchildren, but no ordering property between children •Minimum/Maximum value is always the top element Min-Heap 7 18 9 19 35 14 10 2839 3643 1625 Always a complete tree 2 The number of items in a full d-heap of n levels is (1-d n. A little algebra tells us that the number of levels required to hold n items in a d-heap is log d (n*(d - 1) + 1). So a 4-heap with 21 items takes log 4 (20*(4 - 1)+1), or 2.96 levels. We can’t have a partial level, so we round up to 3. See my blog post, The d-ary heap, for more ...Explanation: d-ary heap is a priority queue based data structure that is a generalization of binary heaps. Sanfoundry Global Education & Learning Series – Data Structure. To practice all areas of Data Structure, here is complete set of 1000+ Multiple Choice Questions and Answers .•Can think of heap as a completebinary tree that maintains the heap property: –Heap Property: Every parent is better-than[less-than if min-heap, or greater-than if max-heap] bothchildren, but no ordering property between children •Minimum/Maximum value is always the top element Min-Heap 7 18 9 19 35 14 10 2839 3643 1625 Always a complete treePrim’s algorithm can be efficiently implemented using _____ for graphs with greater density. a d-ary heap b linear search c fibonacci heap d binary search. BUY.Implement D-ary Heap 4-way. * Description - Implement D-ary Heap (4-way in this case each node has 4 children) max heap, each node has priority level and string value associated. System.out.println ("Error: heap is full!"); // if inserted element is larger we move the parent down, we continue doing this until heap order is correct and insert ... I am using a Dijkstra for finding a shortest path in graph. I used to use std::set but I think a heap could perform better. But I am having troubles using the d_ary_heap or the priority_queue.Show that in the worst case, BUILD-HEAP' requires (n lg n) time to build an n-element heap. 7-2 Analysis of d-ary heaps. A d-ary heap is like a binary heap, but instead of 2 children, nodes have d children. a. How would you represent a d-ary heap in an array? b. What is the height of a d-ary heap of n elements in terms of n and d? c.Prim’s algorithm can be efficiently implemented using _____ for graphs with greater density. a d-ary heap b linear search c fibonacci heap d binary search. BUY.c. Give an efficient implementation of Extract-Max in a d-ary max-heap. (Hint: How would you modify the existing code?) Analyze the running time of your implementation in terms of n and d. (Note that d must be part of your Θexpression even if it occurs in a constant term.) d. Give an efficient implementation of Insert in a d-ary max-heapThe binary heap is a special case of the d-ary heap in which d = 2. Summary of running times. Here are time complexities of various heap data structures. Function names assume a min-heap. For the meaning of "O(f)" and "Θ(f)" see Big O notation.d-ARY-MAX-HEAPIFY (A, i) largest = i for k = 1 to d if d-ARY-CHILD (k, i) ≤ A. heap-size and A [d-ARY-CHILD (k, i)] > A [i] if A [d-ARY-CHILD (k, i)] > largest largest = A [d-ARY-CHILD (k, i)] if largest!= i exchange A [i] with A [largest] d-ARY-MAX-HEAPIFY (A, largest)K-ary heap has better memory cache behaviour than a binary heap which allows them to run more quickly in practice, although it has a larger worst case running time of both extractMin () and delete () operation (both being O (k log k n) ). Implementation:Sep 9, 2016 · 1 Answer. In a ternary heap, each node has up to three children. The heap is represented in the array in breadth-first order, with the root node at 0, and the children of node x at locations (x*3)+1, (x*3)+2, and (x*3)+3. The node at location x is at (x-1)/3. So, your array, [90,82,79,76,46,1,49,44,61,62], looks like this when displayed the ... See Answer. Question: How would you represent a d-ary heap in an array? Answer this question by: Giving an expression for J-th-Child (i,j): the index of the j-th child as a function of the index i of the given node, and the child index j within the given node. Giving an expression for D-Ary-Parent (i): the index of the parent of a node as a ...Jun 30, 2023 · Implementation (Max Heap) We will store the n-ary heap in the form of an array where: The maximum value node will be at the 0th index. The parent of a node at the ith index will be at (i-1)/k. The children of a node at the ith index will be at indices: (k*i)+1, (k*i)+2 … (k*i)+k. getMax (): It returns the maximum element in the heap. b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an efficient implementation of EXTRACT-MAX in a d-ary max-heap. 6-2 Analysis of d-ary heaps. A d-ary heap is like a binary heap, but (with one possible exception) non-leaf. nodes have d children instead of 2 children. a.1 Answer. In a ternary heap, each node has up to three children. The heap is represented in the array in breadth-first order, with the root node at 0, and the children of node x at locations (x*3)+1, (x*3)+2, and (x*3)+3. The node at location x is at (x-1)/3. So, your array, [90,82,79,76,46,1,49,44,61,62], looks like this when displayed the ...Python functions for working with D-ary Heap (Heap with more than 2 child nodes). For more info about this Data Structure Please gothrough: ...Computer Science. Computer Science questions and answers. c++ part 1 answer questions 1) List 5 uses of heaps 2) Define a d-ary heap 3) Define a complete binary heap 4) Why do most implementations of heaps use arrays or vectors 5) What is a heap called a Parent Child sort order heap ? Explanation: Although pairing heap is an efficient algorithm, it is worse than the Fibonacci heap. Also, pairing heap is faster than d-ary heap and binary heap. 13.d-ary heap Article Creation Date : 22-Jun-2021 12:47:06 AM. d-heap: d-heap is generalization of binary heap.it is one kind f advantage in c++.d-heap is a priority ...A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children.. How would you represent a d-ary heap in an array?A d-ary heap can be implemented using a dimensional array as follows.The root is kept in A[1], its d children are kept in order in A[2] through A[d+1] and so on.Jun 1, 2023 · D-ary Heap D-ary heaps are an advanced variation of binary heaps where each internal node can have up to ‘D’ children instead of only (or at most) two. They offer better cache performance and reduced tree height compared to binary heaps, especially for large D values. dary_heap. A priority queue implemented with a d -ary heap. Insertion and popping the largest element have O (log ( n )) time complexity. Checking the largest element is O (1). Converting a vector to a d -ary heap can be done in-place, and has O ( n) complexity. A d -ary heap can also be converted to a sorted vector in-place, allowing it to be ... Binomial Heaps - Princeton University Therefore, the total amount of time to create a heap in this way is. The exact value of the above (the worst-case number of comparisons during the construction of d-ary heap) is known to be equal to:, where s d (n) is the sum of all digits of the standard base-d representation of n and e d (n) is the exponent of d in the factorization of n ... boost::heap::priority_queue. The priority_queue class is a wrapper to the stl heap functions. It implements a heap as container adaptor ontop of a std::vector and is immutable. boost::heap::d_ary_heap. D-ary heaps are a generalization of binary heap with each non-leaf node having N children. For a low arity, the height of the heap is larger ... Sep 9, 2016 · 1 Answer. In a ternary heap, each node has up to three children. The heap is represented in the array in breadth-first order, with the root node at 0, and the children of node x at locations (x*3)+1, (x*3)+2, and (x*3)+3. The node at location x is at (x-1)/3. So, your array, [90,82,79,76,46,1,49,44,61,62], looks like this when displayed the ... D-ary Heap in Java. The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2. Thus, a binary heap is a 2-heap, and a ternary heap is a 3-heap.Explanation: d-ary heap is a priority queue based data structure that is a generalization of binary heaps. Sanfoundry Global Education & Learning Series – Data Structure. To practice all areas of Data Structure, here is complete set of 1000+ Multiple Choice Questions and Answers . Jun 30, 2023 · Implementation (Max Heap) We will store the n-ary heap in the form of an array where: The maximum value node will be at the 0th index. The parent of a node at the ith index will be at (i-1)/k. The children of a node at the ith index will be at indices: (k*i)+1, (k*i)+2 … (k*i)+k. getMax (): It returns the maximum element in the heap. Explanation: Although pairing heap is an efficient algorithm, it is worse than the Fibonacci heap. Also, pairing heap is faster than d-ary heap and binary heap. 13.This C++ Program demonstrates the implementation of D-ary Heap. Here is source code of the C++ Program to demonstrate the implementation of D-ary Heap. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below. /* * C++ Program to Implement D-ary-Heap */#include <iostream>#include <cstring>#include <cstdlib>using namespace std;/* * D-ary ... A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children.. How would you represent a d-ary heap in an array?A d-ary heap can be implemented using a dimensional array as follows.The root is kept in A[1], its d children are kept in order in A[2] through A[d+1] and so on.A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children.. How would you represent a d-ary heap in an array?A d-ary heap can be implemented using a dimensional array as follows.The root is kept in A[1], its d children are kept in order in A[2] through A[d+1] and so on.Computer Science. Computer Science questions and answers. c++ part 1 answer questions 1) List 5 uses of heaps 2) Define a d-ary heap 3) Define a complete binary heap 4) Why do most implementations of heaps use arrays or vectors 5) What is a heap called a Parent Child sort order heap ?Internally, the d-ary heap is represented as dynamically sized array (std::vector), that directly stores the values. The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used. Computer Science. Computer Science questions and answers. c++ part 1 answer questions 1) List 5 uses of heaps 2) Define a d-ary heap 3) Define a complete binary heap 4) Why do most implementations of heaps use arrays or vectors 5) What is a heap called a Parent Child sort order heap ?K-ary heap has better memory cache behaviour than a binary heap which allows them to run more quickly in practice, although it has a larger worst case running time of both extractMin () and delete () operation (both being O (k log k n) ). Implementation:Dec 7, 2012 · 1 Answer. From the explanation itself you can deduct that you have n delete min operations each requiring O (d log (n)/log (d)) and m decrease priority operations of O (log (n)/log (d)). The combined work is then (m*log (n)+n*d*log (n))/log (d). If you fill in the suggested d value, the global behavior is as stated O (m*log (n)/log (d)). Feb 6, 2019 · Development. After checking out the repo, cd to the repository. Then, run pip install . to install the package locally. You can also run python (or) python3 for an interactive prompt that will allow you to experiment. Question. A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children. a. How would you represent a d-ary heap in an array? b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an efficient implementation of EXTRACT-MAX in a d-ary max-heap. Analyze its ...When creating a d-ary heap from a set of n items, most of the items are in positions that will eventually hold leaves of the d-ary tree, and no downward swapping is performed for those items. At most n / d + 1 items are non-leaves, and may be swapped downwards at least once, at a cost of O( d ) time to find the child to swap them with.Question. A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children. a. How would you represent a d-ary heap in an array? b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an efficient implementation of EXTRACT-MAX in a d-ary max-heap. Analyze its ...The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2. Thus, a binary heap is a 2-heap, and a ternary heap is a 3-heap. According to Tarjan and Jensen et al., d-ary heaps were invented by Donald B. Johnson in 1975.node has d children. It is an almost complete,d-ary tre, and a node must be less than or equal to all its children. Design an array representation of the heap. Design a Deletemin and Increasekey procedure here. Solution: We generalize the representation of a 2-ary (binary) heap to a d -ary heap. Root is stored in array element 0. The children ... Contact Datils (You can follow me at)Instagram: https://www.instagram.com/ahmadshoebkhan/LinkedIn: https://www.linkedin.com/in/ahmad-shoeb-957b6364/Faceboo...2 The number of items in a full d-heap of n levels is (1-d n. A little algebra tells us that the number of levels required to hold n items in a d-heap is log d (n*(d - 1) + 1). So a 4-heap with 21 items takes log 4 (20*(4 - 1)+1), or 2.96 levels. We can’t have a partial level, so we round up to 3. See my blog post, The d-ary heap, for more ...DHeap - Fast d-ary heap for ruby. A fast d -ary heap priority queue implementation for ruby, implemented as a C extension. A regular queue has "FIFO" behavior: first in, first out. A stack is "LIFO": last in first out. A priority queue pushes each element with a score and pops out in order by score. Priority queues are often used in algorithms ...May 9, 2017 · When the tree in question is the infinite d-ary tree, this algorithm becomes (naively) initialize a queue Q = [1] nextID = 2 forever (Q is always nonempty) pop the head of Q into v repeat d times let w = nextID (w is a child of v) increment nextChildID push w into Q (d.) The procedure MAX-HEAP-INSERT given in the text for binary heaps works fine for d-ary heaps too. The worst-case running time is still O(h), where h is the height of the heap. (Since only parent pointers are followed, the numberof children a node has is irrelevant.) For a d-ary heap, this is O(log d n) =O(lg n/ lg d). (e.)May 6, 2015 · 1. In a d-ary heap, up-heaps (e.g., insert, decrease-key if you track heap nodes as they move around) take time O (log_d n) and down-heaps (e.g., delete-min) take time O (d log_d n), where n is the number of nodes. The reason that down-heaps are more expensive is that we have to find the minimum child to promote, whereas up-heaps just compare ... Internally, the d-ary heap is represented as dynamically sized array (std::vector), that directly stores the values. The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used. D-ary Heap in Java. The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2. Thus, a binary heap is a 2-heap, and a ternary heap is a 3-heap.boost::heap::priority_queue. The priority_queue class is a wrapper to the stl heap functions. It implements a heap as container adaptor ontop of a std::vector and is immutable. boost::heap::d_ary_heap. D-ary heaps are a generalization of binary heap with each non-leaf node having N children. For a low arity, the height of the heap is larger ... Aug 10, 2019 · A d-ary heap is just like a regular heap but instead of two childrens to each element, there are d childrens! d is given when building a heap, either by giving an argument or by passing it while calling init. Here is my Implementation: import math class DHeap: ''' creates d-heap ''' ''' heap: A python's list ''' def __init__ (self, heap: list ... We would like to show you a description here but the site won’t allow us. Sep 9, 2016 · 1 Answer. In a ternary heap, each node has up to three children. The heap is represented in the array in breadth-first order, with the root node at 0, and the children of node x at locations (x*3)+1, (x*3)+2, and (x*3)+3. The node at location x is at (x-1)/3. So, your array, [90,82,79,76,46,1,49,44,61,62], looks like this when displayed the ... Contact Datils (You can follow me at)Instagram: https://www.instagram.com/ahmadshoebkhan/LinkedIn: https://www.linkedin.com/in/ahmad-shoeb-957b6364/Faceboo...1. In a d-ary heap, up-heaps (e.g., insert, decrease-key if you track heap nodes as they move around) take time O (log_d n) and down-heaps (e.g., delete-min) take time O (d log_d n), where n is the number of nodes. The reason that down-heaps are more expensive is that we have to find the minimum child to promote, whereas up-heaps just compare ...The d-ary heap or d-heap is a priority queue data structure, a generalization of the binary heap in which the nodes have d children instead of 2 This data structure allows decrease priority operations to be performed more quickly than binary heaps, at the expense of slower delete minimum operations. Python functions for working with D-ary Heap (Heap with more than 2 child nodes). For more info about this Data Structure Please gothrough: ...
We would like to show you a description here but the site won’t allow us.. Sdgande san diego
Based on my understanding, different questions where HEAP is common data structure to use can be categorized in following 4 categories: Top K Pattern. Merge K Sorted Pattern. Two Heaps Pattern. Minimum Number Pattern. All questions under one patterns has some similarities in terms of using HEAP as a data structure.1 Answer. From the explanation itself you can deduct that you have n delete min operations each requiring O (d log (n)/log (d)) and m decrease priority operations of O (log (n)/log (d)). The combined work is then (m*log (n)+n*d*log (n))/log (d). If you fill in the suggested d value, the global behavior is as stated O (m*log (n)/log (d)).Jul 16, 2015 · I implemented a D-ary max heap backed by a vector for resizing. I would like to know any possible improvements in performance, design, and in the code in general. #pragma once #include <vector... A d -ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children. How would you represent a d -ary heap in an array? What is the height of a d -ary heap of n elements in terms of n and d? Give an efficient implementation of EXTRACT-MAX in a d -ary max-heap.Jun 30, 2023 · Implementation (Max Heap) We will store the n-ary heap in the form of an array where: The maximum value node will be at the 0th index. The parent of a node at the ith index will be at (i-1)/k. The children of a node at the ith index will be at indices: (k*i)+1, (k*i)+2 … (k*i)+k. getMax (): It returns the maximum element in the heap. 1 Answer. Add the d parameter to all your functions, and generalise. The formula for where to start the heapify function is (num + 1) // d - 1. Where you have left and right indices and choose the one that has the greatest value, instead iterate the children in a for loop to find the child with the greatest value.1 Answer. In your insert, percolateUp and percolateDown methods, you need to use getParent () and getChild () methods. Currently, insert method divides indexes by 2 to get to the parent of an element which is only true if you have a 2-heap. Also, your heap implementation uses array [0] as a placeholder. In that case, your getParent () and ...5. (CLRS 6-2) Analysis of d-ary heaps A d-ary heap is like a binary heap, but instead of 2 children, nodes have d children. a. How would you represent a d-ary heap in a array? b. What is the height of a d-ary heap of n elements in terms of n and d? c. Give an e cient implementation of Extract-Max. Analyze its running time in terms of d and n. d.Explanation: d-ary heap is a priority queue based data structure that is a generalization of binary heaps. Sanfoundry Global Education & Learning Series – Data Structure. To practice all areas of Data Structure, here is complete set of 1000+ Multiple Choice Questions and Answers .2 Answers. Sorted by: 4. This uses the common identity to convert between logarithmic bases: logx(z) = logm(z) / logm(x) By multiplying both sides by log m (x), you get: logm(z) = logx(z) * logm(x) Which is equivalent to the answer in the question you site. More information is available here.ヒープ （ 英: heap ）とは、「子要素は親要素より常に大きいか等しい（または常に小さいか等しい）」という制約を持つ 木構造 の事。. 単に「ヒープ」という場合、 二分木 を使った 二分ヒープ を指すことが多いため、そちらを参照すること。. 二分ヒープ ... A d-ary heap is like a binary heap, but (with one possible exception) non-leaf nodes have d children instead of 2 children. . a. How would you represent a d-ary heap in an array? . b. What is the height of a d-ary heap of n elements in terms of n and d? . c. Give an efficient implementation of EXTRACT-MAX in a d-ary max-heap..