[LeetCode] 215. Kth Largest Element in an Array

Posted 2020-10-13

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

For example,
Given [3,2,1,5,6,4] and k = 2, return 5.

class Solution {
    public int findKthLargest(int[] nums, int k) {
        PriorityQueue<Integer> queue = new PriorityQueue<>();
        
        for (int num : nums) {
            queue.offer(num);
            if (queue.size() > k) {
                queue.poll();
            }
        }
        
        return queue.peek();
    }
}

class Solution {
    public int findKthLargest(int[] nums, int k) {
        Arrays.sort(nums);
        return nums[nums.length - k];
    }
}

 

PriorityQueue()

Creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering.

natural ordering: 1 2 3 4 5 6 7 10 11 12 20 21 (reference)