215. Kth Largest Element in an Array

Medium


Given an integer array nums and an integer k, return the kth largest element in the array.

Note that it is the kth largest element in the sorted order, not the kth distinct element.

You must solve it in O(n) time complexity.

 

Example 1:

Input: nums = [3,2,1,5,6,4], k = 2
Output: 5

Example 2:

Input: nums = [3,2,3,1,2,4,5,5,6], k = 4
Output: 4

 

Constraints:

  • 1 <= k <= nums.length <= 105
  • -104 <= nums[i] <= 104




 class Solution:
    def findKthLargest(self, nums: List[int], k: int) -> int:

        #nums = [x*-1 for x in nums]
#         heapq.heapify(nums)

#         for i in range(len(nums)):
#             num = nums[0]
#             heapq.heappop(nums)

#             if i == k-1:
#                 return -num

        heap = nums[:k]
        heapq.heapify(heap)
        for num in nums[k:]:
            if num > heap[0]:
                heapq.heappushpop(heap, num)

        return heap[0]

Random Note


when you have something circular, most of the time you can have one variableand another can be calculated using size, current value and doing %