Description
Design a class to find the kth largest element in a stream. Note that it is the kth largest element in the sorted order, not the kth distinct element.
Your KthLargest
class will have a constructor which accepts an integer k
and an integer array nums
, which contains initial elements from the stream. For each call to the method KthLargest.add
, return the element representing the kth largest element in the stream.
Example:
int k = 3;
int[] arr = [4,5,8,2];
KthLargest kthLargest = new KthLargest(3, arr);
kthLargest.add(3); // returns 4
kthLargest.add(5); // returns 5
kthLargest.add(10); // returns 5
kthLargest.add(9); // returns 8
kthLargest.add(4); // returns 8
Note:
You may assume that nums
’ length ≥ k-1
and k
≥ 1.
Solutions
1. Heap
# Time: O(n)
# Space: O(n)
class KthLargest:
def __init__(self, k: int, nums: List[int]):
self.nums = nums
self.k = k
heapq.heapify(self.nums)
while len(nums) > k:
heapq.heappop(self.nums)
def add(self, val: int) -> int:
if len(self.nums) < self.k:
heapq.heappush(self.nums, val)
elif val > self.nums[0]:
heapq.heapreplace(self.nums, val)
return self.nums[0]
# Your KthLargest object will be instantiated and called as such:
# obj = KthLargest(k, nums)
# param_1 = obj.add(val)
# 10/10 cases passed (88 ms)
# Your runtime beats 97.43 % of python3 submissions
# Your memory usage beats 82.61 % of python3 submissions (16.6 MB)