Kth Largest Element in a Stream.cpp

/*
Kth Largest Element in a Stream
===============================

Design a class to find the kth largest element in a stream. Note that it is the kth largest element in the sorted order, not the kth distinct element.

Implement KthLargest class:

KthLargest(int k, int[] nums) Initializes the object with the integer k and the stream of integers nums.
int add(int val) Returns the element representing the kth largest element in the stream.

Example 1:
Input
["KthLargest", "add", "add", "add", "add", "add"]
[[3, [4, 5, 8, 2]], [3], [5], [10], [9], [4]]
Output
[null, 4, 5, 5, 8, 8]

Explanation
KthLargest kthLargest = new KthLargest(3, [4, 5, 8, 2]);
kthLargest.add(3);   // return 4
kthLargest.add(5);   // return 5
kthLargest.add(10);  // return 5
kthLargest.add(9);   // return 8
kthLargest.add(4);   // return 8

Constraints:
1 <= k <= 104
0 <= nums.length <= 104
-104 <= nums[i] <= 104
-104 <= val <= 104
At most 104 calls will be made to add.
It is guaranteed that there will be at least k elements in the array when you search for the kth element.
*/

class KthLargest
{
public:
  priority_queue<int, vector<int>, greater<int>> pq;
  int k;

  KthLargest(int k, vector<int> &nums)
  {
    this->k = k;
    for (int i = 0; i < nums.size(); ++i)
    {
      if (pq.size() < k)
        pq.push(nums[i]);
      else
      {
        if (pq.top() < nums[i])
        {
          pq.pop();
          pq.push(nums[i]);
        }
      }
    }
  }

  int add(int num)
  {
    if (pq.size() < k)
      pq.push(num);
    else
    {
      if (pq.top() < num)
      {
        pq.pop();
        pq.push(num);
      }
    }
    return pq.top();
  }
};

/**
 * Your KthLargest object will be instantiated and called as such:
 * KthLargest* obj = new KthLargest(k, nums);
 * int param_1 = obj->add(val);
 */