Kth Largest Element Using Max Heap in DSA C++ - Build from Scratch

Kth Largest Element Using Max Heap

📖 Scenario: You have a list of exam scores from students. You want to find the kth largest score to see who scored in the top group.

🎯 Goal: Build a program that uses a max heap to find the kth largest element from a list of numbers.

📋 What You'll Learn

Create a vector called scores with the exact values: 85, 92, 78, 90, 88, 76, 95

Create an integer variable called k and set it to 3

Use a max heap to find the kth largest score

Print the kth largest score using std::cout

💡 Why This Matters

🌍 Real World

Finding the kth largest value is useful in ranking systems, like finding the top scores in exams or competitions.

💼 Career

Understanding heaps and priority queues is important for software roles involving data processing, optimization, and real-time systems.

1

Create the scores vector

Create a std::vector<int> called scores with these exact values: 85, 92, 78, 90, 88, 76, 95

DSA C++

#include 
#include 

int main() {
    // Create the scores vector with given values
    // Your code here
}

Hint

Use std::vector<int> scores = {85, 92, 78, 90, 88, 76, 95}; to create the vector.

2

Set the value of k

Create an integer variable called k and set it to 3 inside main()

DSA C++

#include 
#include 

int main() {
    std::vector scores = {85, 92, 78, 90, 88, 76, 95};
    // Create variable k and set it to 3
    // Your code here
}

Hint

Write int k = 3; inside main().

3

Use a max heap to find the kth largest element

Use std::priority_queue<int> called maxHeap to store all elements from scores. Then pop from maxHeap exactly k - 1 times to remove the largest elements before the kth largest. Finally, store the top element of maxHeap in an integer variable called kthLargest

DSA C++

#include 
#include 
#include 

int main() {
    std::vector scores = {85, 92, 78, 90, 88, 76, 95};
    int k = 3;
    // Create maxHeap and push all scores
    // Pop k-1 times
    // Store top element in kthLargest
    // Your code here
}

Hint

Use std::priority_queue<int> maxHeap; and push all scores. Then pop k - 1 times. Finally, get the top element.

4

Print the kth largest score

Print the value of kthLargest using std::cout followed by a newline

DSA C++

#include 
#include 
#include 

int main() {
    std::vector scores = {85, 92, 78, 90, 88, 76, 95};
    int k = 3;
    std::priority_queue maxHeap;
    for (int score : scores) {
        maxHeap.push(score);
    }
    for (int i = 0; i < k - 1; i++) {
        maxHeap.pop();
    }
    int kthLargest = maxHeap.top();
    // Print kthLargest
    // Your code here
}

Hint

Use std::cout << kthLargest << std::endl; to print the result.