703. Kth Largest Element in a Stream

class KthLargest {

    private final Queue<Integer> minHeap; // 小顶堆
    private final int k;

    public KthLargest(int k, int[] nums) {
        this.minHeap = new PriorityQueue<>();
        this.k = k;

        for (int num : nums) {
            add(num);
        }
    }

    public int add(int val) {
        if (minHeap.size() < k) {
            minHeap.offer(val);
        } else {
            if (val > minHeap.peek()) {
                minHeap.offer(val);
                minHeap.poll();
            }
        }

        return minHeap.peek();
    }

}

Reference