Kth smallest element after every insertion in C++

In this tutorial, we are going to find the k-th smallest element after every insertion.

We are going to use the min-heap to solve the problem. Let's see the steps to complete the program.

• Initialise the array with random data.
• Initialise the priority queue.
• Till k - 1 there won't be any k-th smallest element. So, print any symbol u like.
• Write a loop that iterates from k + 1 to n.
  • Print the root of the min-heap.
  • If the element is greater than the root of the min-heap, then pop the root and insert the element.

Example

Let's see the code.

 Live Demo

#include <bits/stdc++.h>
using namespace std;
void findKthSmallestElement(int elements[], int n, int k) {
   priority_queue<int, vector<int>, greater<int>> queue;
   for (int i= 0; i < k - 1; i++) {
      queue.push(elements[i]);
      cout << "- ";
   }
   queue.push(elements[k-1]);
   for (int i = k; i < n; i++) {
      cout << queue.top() << " ";
      if (elements[i] > queue.top()) {
         queue.pop();
         queue.push(elements[i]);
      }
   }
   cout << queue.top() << endl;
}
int main() {
   int arr[] = {3, 5, 6, 2, 7, 8, 2, 3, 5, 9};
   findKthSmallestElement(arr, 10, 5);
   return 0;
}

Output

If you run the above code, then you will get the following result.

- - - - 2 3 3 3 5 5

Conclusion

If you have any queries in the tutorial, mention them in the comment section.