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63 lines
1.5 KiB
Plaintext
63 lines
1.5 KiB
Plaintext
---
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title: '215. Kth Largest Element in an Array'
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description: Given an integer array nums and an integer k, return the k^th largest element in the array
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icon: dot
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topics:
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- { name: "Array", slug: "array" }
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- { name: "Divide and Conquer", slug: "divide-and-conquer" }
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- { name: "Sorting", slug: "sorting" }
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- { name: "Heap (Priority Queue)", slug: "heap-priority-queue" }
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- { name: "Quickselect", slug: "quickselect" }
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video: "XEmy13g1Qxc"
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issue: "https://github.com/prdlk/leetcode/issues/118"
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sidebar:
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label: 'Kth Largest Element in an Array'
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badge: 'Medium'
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---
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### Example 1:
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- Input: `nums = [3,2,1,5,6,4], k = 2`
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- Output: `5`
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### Example 2:
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- Input: `nums = [3,2,3,1,2,4,5,5,6], k = 4`
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- Output: `4`
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### Constraints:
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- `1 <= k <= nums.length <= 10^5`
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- `-10^4 <= nums[i] <= 10^4`
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## Approach
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```mermaid
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flowchart TD
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S(["findKthLargest(nums, k)"]) --> F{"more i in range(len(nums))?"}
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F -- yes --> N["nums[i] = -nums[i] — negate so the min-heap acts as a max-heap"]
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N --> F
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F -- no --> H["heapq.heapify(nums)"]
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H --> W{"more _ in range(k - 1)?"}
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W -- yes --> P["heapq.heappop(nums) — discard the k-1 largest"]
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P --> W
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W -- no --> E(["return -heapq.heappop(nums)"])
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```
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## Solution
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```py
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import heapq
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class Solution:
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def findKthLargest(self, nums: List[int], k: int) -> int:
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for i in range(len(nums)):
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nums[i] = -nums[i]
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heapq.heapify(nums)
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for _ in range(k - 1):
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heapq.heappop(nums)
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return -heapq.heappop(nums)
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```
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