Heap vs Priority Queue

Add Answer

Javasper answered on May 1, 2021 Popularity 9/10 Helpfulness 2/10

answer Heap vs Priority Queue

related min heap and max heap using priority queue

related Difference between Priority Queue and Heap

related priority queue with min heap

related priority queue using heap

Heap vs Priority Queue

Comment

A priority queue is not a data structure, it is abstract. It does not say how things are implemented.
A heap IS a data structure. It specifies how things are implemented
In the real world, we implement heaps

Popularity 9/10 Helpfulness 2/10 Language whatever

Source: Grepper

Tags: heap priority-queue whatever

Link to this answer
Share Copy Link

Contributed on Jul 25 2022

Javasper

0 Answers Avg Quality 2/10

Closely Related Answers

min heap and max heap using priority queue

Comment

#include <bits/stdc++.h>
#define cl cout << endl;
using namespace std;
int main()
{
    priority_queue<int, vector<int>,greater<int>> pqm; //min heap
    priority_queue<int, vector<int>> pq;  //max heap
    vector<int> v = {100, 2, 89, 36, 42, 91, 555};

    for (int i = 0; i < v.size(); i++)
    {

        pq.push(v[i]);
        pqm.push(v[i]);
        

        // pq.push(temp);
    }

        cout<<"max heap is: ";
        cl

        while (!pq.empty())
        {
            int temp = pq.top();
            pq.pop();
            cout << temp << endl;
        }

        cout<<"min heap is: ";
        cl

        while (!pqm.empty())
        {
            int temp = pqm.top();
            pqm.pop();
            cout << temp << endl;
        }

    return 0;
}

Popularity 10/10 Helpfulness 5/10 Language cpp

Source: Grepper

Tags: c++

Link to this answer
Share Copy Link

Contributed on Sep 13 2021

Delightful Duck

0 Answers Avg Quality 2/10

Difference between Priority Queue and Heap

Comments(1)

This website provides a really clear explanation. http://pages.cs.wisc.edu/~vernon/cs367/notes/11.PRIORITY-Q.html

In short, a priority queue can be implemented using many of the data structures that we've already studied (an array, a linked list, or a binary search tree). However, those data structures do not provide the most efficient operations. To make all of the operations very efficient, we'll use a new data structure called a heap.

Popularity 10/10 Helpfulness 4/10 Language whatever

Source: softwareengineering.stackexchange.com

Tags: between

Link to this answer
Share Copy Link

Contributed on May 01 2021

Exuberant Eel

0 Answers Avg Quality 2/10

priority queue with min heap

Comment

This is frequently used in Competitive Programming.
We first multiply all elements with (-1). Then we create a max heap (max heap is the default for priority queue). 
When we access the data and want to print it we simply multiply those elements with (-1) again.

Popularity 10/10 Helpfulness 1/10 Language whatever

Source: Grepper

Tags: min-heap min-hea

Link to this answer
Share Copy Link

Contributed on Jul 31 2021

vizard

0 Answers Avg Quality 2/10

priority queue using heap

Comment

-1

// C++ code to implement priority-queue
// using array implementation of
// binary heap
 
#include <bits/stdc++.h>
using namespace std;
 
int H[50];
int size = -1;
 
// Function to return the index of the
// parent node of a given node
int parent(int i)
{
 
    return (i - 1) / 2;
}
 
// Function to return the index of the
// left child of the given node
int leftChild(int i)
{
 
    return ((2 * i) + 1);
}
 
// Function to return the index of the
// right child of the given node
int rightChild(int i)
{
 
    return ((2 * i) + 2);
}
 
// Function to shift up the node in order
// to maintain the heap property
void shiftUp(int i)
{
    while (i > 0 && H[parent(i)] < H[i]) {
 
        // Swap parent and current node
        swap(H[parent(i)], H[i]);
 
        // Update i to parent of i
        i = parent(i);
    }
}
 
// Function to shift down the node in
// order to maintain the heap property
void shiftDown(int i)
{
    int maxIndex = i;
 
    // Left Child
    int l = leftChild(i);
 
    if (l <= size && H[l] > H[maxIndex]) {
        maxIndex = l;
    }
 
    // Right Child
    int r = rightChild(i);
 
    if (r <= size && H[r] > H[maxIndex]) {
        maxIndex = r;
    }
 
    // If i not same as maxIndex
    if (i != maxIndex) {
        swap(H[i], H[maxIndex]);
        shiftDown(maxIndex);
    }
}
 
// Function to insert a new element
// in the Binary Heap
void insert(int p)
{
    size = size + 1;
    H[size] = p;
 
    // Shift Up to maintain heap property
    shiftUp(size);
}
 
// Function to extract the element with
// maximum priority
int extractMax()
{
    int result = H[0];
 
    // Replace the value at the root
    // with the last leaf
    H[0] = H[size];
    size = size - 1;
 
    // Shift down the replaced element
    // to maintain the heap property
    shiftDown(0);
    return result;
}
 
// Function to change the priority
// of an element
void changePriority(int i, int p)
{
    int oldp = H[i];
    H[i] = p;
 
    if (p > oldp) {
        shiftUp(i);
    }
    else {
        shiftDown(i);
    }
}
 
// Function to get value of the current
// maximum element
int getMax()
{
 
    return H[0];
}
 
// Function to remove the element
// located at given index
void remove(int i)
{
    H[i] = getMax() + 1;
 
    // Shift the node to the root
    // of the heap
    shiftUp(i);
 
    // Extract the node
    extractMax();
}
 
// Driver Code
int main()
{
 
    /*         45
            /      \
           31      14
          /  \    /  \
         13  20  7   11
        /  \
       12   7
    Create a priority queue shown in
    example in a binary max heap form.
    Queue will be represented in the
    form of array as:
    45 31 14 13 20 7 11 12 7 */
 
    // Insert the element to the
    // priority queue
    insert(45);
    insert(20);
    insert(14);
    insert(12);
    insert(31);
    insert(7);
    insert(11);
    insert(13);
    insert(7);
 
    int i = 0;
 
    // Priority queue before extracting max
    cout << "Priority Queue : ";
    while (i <= size) {
        cout << H[i] << " ";
        i++;
    }
 
    cout << "\n";
 
    // Node with maximum priority
    cout << "Node with maximum priority : "
         << extractMax() << "\n";
 
    // Priority queue after extracting max
    cout << "Priority queue after "
         << "extracting maximum : ";
    int j = 0;
    while (j <= size) {
        cout << H[j] << " ";
        j++;
    }
 
    cout << "\n";
 
    // Change the priority of element
    // present at index 2 to 49
    changePriority(2, 49);
    cout << "Priority queue after "
         << "priority change : ";
    int k = 0;
    while (k <= size) {
        cout << H[k] << " ";
        k++;
    }
 
    cout << "\n";
 
    // Remove element at index 3
    remove(3);
    cout << "Priority queue after "
         << "removing the element : ";
    int l = 0;
    while (l <= size) {
        cout << H[l] << " ";
        l++;
    }
    return 0;
}

Popularity 10/10 Helpfulness 1/10 Language cpp

Source: www.geeksforgeeks.org

Tags: c++

Link to this answer
Share Copy Link

Contributed on Dec 29 2021

Lucky Lobster

0 Answers Avg Quality 2/10

Heap vs Priority Queue

Contents

More Related Answers

Heap vs Priority Queue

Closely Related Answers

min heap and max heap using priority queue

Difference between Priority Queue and Heap

priority queue with min heap

priority queue using heap

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.