tmp/tmpg737dcz5/{from.md → to.md}
RENAMED
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| 1 |
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### Sample <a id="alg.random.sample">[[alg.random.sample]]</a>
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``` cpp
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template<class PopulationIterator, class SampleIterator,
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class Distance, class UniformRandomBitGenerator>
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SampleIterator sample(PopulationIterator first, PopulationIterator last,
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SampleIterator out, Distance n,
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UniformRandomBitGenerator&& g);
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```
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*Requires:*
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- `PopulationIterator` shall satisfy the requirements of an input
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iterator ([[input.iterators]]).
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- `SampleIterator` shall satisfy the requirements of an output
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iterator ([[output.iterators]]).
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- `SampleIterator` shall satisfy the additional requirements of a random
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access iterator ([[random.access.iterators]]) unless
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`PopulationIterator` satisfies the additional requirements of a
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forward iterator ([[forward.iterators]]).
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- `PopulationIterator`’s value type shall be
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writable ([[iterator.requirements.general]]) to `out`.
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- `Distance` shall be an integer type.
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- `remove_reference_t<UniformRandomBitGenerator>` shall meet the
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requirements of a uniform random bit generator type
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([[rand.req.urng]]) whose return type is convertible to `Distance`.
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- `out` shall not be in the range \[`first`, `last`).
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*Effects:* Copies `min(last - first, n)` elements (the *sample*) from
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\[`first`, `last`) (the *population*) to `out` such that each possible
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sample has equal probability of appearance.
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[*Note 1*: Algorithms that obtain such effects include *selection
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sampling* and *reservoir sampling*. — *end note*]
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*Returns:* The end of the resulting sample range.
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*Complexity:* 𝑂(`last - first`).
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*Remarks:*
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- Stable if and only if `PopulationIterator` satisfies the requirements
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of a forward iterator.
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- To the extent that the implementation of this function makes use of
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random numbers, the object `g` shall serve as the implementation’s
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source of randomness.
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