703. 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
[[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]);
```

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.

703. Kth Largest Element in a Stream
``````use std::cmp::Reverse;
use std::collections::BinaryHeap;

struct KthLargest {
pq: BinaryHeap<Reverse<i32>>,
k: usize,
}

impl KthLargest {
fn new(k: i32, nums: Vec<i32>) -> Self {
let mut pq: BinaryHeap<Reverse<i32>> = BinaryHeap::new();
let k = k as usize;
for x in nums {
pq.push(Reverse(x));
if pq.len() > k {
pq.pop();
}
}
KthLargest { pq, k }
}

fn add(&mut self, val: i32) -> i32 {
self.pq.push(Reverse(val));
if self.pq.len() > self.k {
self.pq.pop();
}
let x = *self.pq.peek().unwrap();
x.0
}
}

#[test]
fn test() {
let k = 3;
let nums = vec![4, 5, 8, 2];
let mut obj = KthLargest::new(k, nums);