Kth Largest Element in an Array

Java

// solution1 : MaxHeap
class Solution {
		public int findKthLargest(int[] nums, int k) {
			PriorityQueue<Integer> heap = new PriorityQueue<Integer>((a, b) -> (a - b));
			for (int num : nums) {
				heap.add(num);
				if (heap.size() > k) heap.poll();
			}
			return heap.poll();
		}
}

// Time Complexity : O(nlogk); // add an element in a heap of size k is O(logk);
// Space Complexity : O(k);


// solution2:MinHeap
class Solution {
		public int findKthLargest(int[] nums, int k) {
		PriorityQueue<Integer> heap = new PriorityQueue<Integer>((a, b) -> (b - a));
		for (int num : nums) {
			heap.add(num);
		}
	
		for (int i = 0; i < k - 1; i++) {
			heap.poll();
		}
		return heap.poll();
	}
}