Question

Create a heapsort function in C++ using priority_queue in a vector. The vector contains 20 numbers with varying numbers between 0-20 with some duplicates. From what I understand this should only take around 6 lines with the brackets. The heapsort just needs to put the numbers in order from 0-20 using the priority queue. priority queue is implemented using #include <queue> and the function also includes <algorithm> .

Use this as a base:

template

void heapsorter(std::vector& vec) {

}

Answer 1

CODE:

#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <ctime>
using namespace std;
//using thee given template we define the heapsort function
void heapsort(vector<int>& vec){

   //We implement the heapsort algorithm using min-heap , as we want to sort thre values in ascending order
   //Given below is the definition of a min-heap using priority queue.We use the greater comparator to implement sorting in ascending order
   //If the vector is to be sorted in decreasing order , the priority_queue should be definedd in the following manner:

   // priority_queue<int> pri_queue;

   priority_queue<int , vector<int>,greater <int>> pri_queue;
   // we push each element of the vector using the push() function.
   for(int i =0;i<vec.size();i++){
       pri_queue.push(vec[i]);
   }
   //Printing the queue elements one by one by popping them of from the queue top.
   cout<<"\nSORTED VALUES ARE ";
   while(pri_queue.empty() == false){
       cout<<pri_queue.top()<<" ";
       pri_queue.pop();
   }
}

int main(){
   //this is used to generate new valus with every execution of the program
   srand(time(NULL));
   //we define a vector to store 20 values from 0-20 with duplicates.
   vector<int> vec;
   cout<<"Vector elements are : ";
   for(int i=0;i<20;i++){
       //this is used to push values into the vector from 0-20 with duplicates
       vec.push_back(rand()%21);
       cout<<vec[i]<<" ";
   }
   // we call the heapsort function to sort the vector in increasing order.
   heapsort(vec);

}

OUTPUT:

Screenshot of code: