解决思路

堆

public class KthLargest {
    private PriorityQueue<Integer> queue;
    private int limit;
    public KthLargest(int k, int[] nums) {
        limit = k;
        queue = new PriorityQueue<>(k);
        for (int num : nums) {
            add(num);
        }
    }
    public int add(int val) {
        if (queue.size() < limit) {
            queue.add(val);
        } else if (val > queue.peek()) {
            queue.poll();
            queue.add(val);
        }
        return queue.peek();
    }
}