84 lines
1.3 KiB
Markdown
84 lines
1.3 KiB
Markdown
---
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layout: page
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title: Kth Largest Element in an Array
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last_solved:
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category: heap
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leetcode_url: https://leetcode.com/problems/kth-largest-element-in-an-array/
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status: Attempted
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---
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Problem
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-------
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```
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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.
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Example 1:
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Input: [3,2,1,5,6,4] and k = 2
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Output: 5
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Example 2:
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Input: [3,2,3,1,2,4,5,5,6] and k = 4
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Output: 4
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```
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Solution
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----------
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- If you're trying to find the largest kth element, use a min heap.
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- As you're adding elements, evict elements if length is greater than k
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- The result is the kth largest element sitting at the root
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{% highlight python %}
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def findKthLargest(self, nums: List[int], k: int) -> int:
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min_heap = []
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for n in nums:
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heapq.heappush(min_heap, n)
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print(min_heap) # added element n
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# if len>5, pop the smallest element (make room for a LARGER one)
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if len(min_heap)>k:
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heapq.heappop(min_heap)
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print(min_heap)
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print()
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return heapq.heappop(min_heap) # can also do `return min_heap[0]`
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{% endhighlight %}
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```
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Your input
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[3,2,1,5,6,4]
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k=2
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stdout
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[3]
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[3]
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[2, 3]
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[2, 3]
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[1, 3, 2]
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[2, 3]
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[2, 3, 5]
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[3, 5]
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[3, 5, 6]
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[5, 6]
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[4, 6, 5]
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[5, 6]
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```
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![image1]() |