Level 5Exercise #105

K largest from a stream

Return the k largest streamed values using O(k) extra space.

What you’ll practice

This Level 5 exercise focuses on bounded min-heap in the Algorithms curriculum. Solve the challenge prompt above using clear, idiomatic Python and the relevant language or standard-library tools.

Relevant Python reference: heapq — Heap queue algorithm.

Sample Test Cases

Example #1

Input:k_largest([4,9,1,7,3], k=2)

Output:[9,7]

Reference Solution

Reveal Reference Solution

def k_largest(stream, k: int) -> list[int]:
    import heapq
    heap = []
    for value in stream:
        if len(heap) < k: heapq.heappush(heap, value)
        elif value > heap[0]: heapq.heapreplace(heap, value)
    return sorted(heap, reverse=True)

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K largest from a stream

What you’ll practice

Sample Test Cases

Further Reading

Reference Solution