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Refactor random-choice

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Prefer initializing `result` to an empty array of size `m`, which makes the
algorithm a bit more elegant.
This commit is contained in:
William Carroll 2020-11-17 23:54:54 +00:00
parent 751b5327a9
commit c0268ed31a
1 changed files with 2 additions and 2 deletions
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4
scratch/facebook/hard/random-choice.py
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@ -6,8 +6,8 @@ def choose_a(m, xs):
Randomly choose `m` elements from `xs`. Randomly choose `m` elements from `xs`.
This algorithm runs in linear time with respect to the size of `xs`. This algorithm runs in linear time with respect to the size of `xs`.
""" """
result = xs[:m] result = [None] * m
for i in range(m, len(xs)): for i in range(len(xs)):
j = random.randint(0, i) j = random.randint(0, i)
if j < m: if j < m:
result[j] = xs[i] result[j] = xs[i]