std::nth_element

 

C++

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正規表現ライブラリ(C++11)

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スレッドのサポートライブラリ(C++11)

 

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機能します Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
シーケンス動作を非改変 Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of (C++11) (C++11) (C++11) for_each count count_if mismatch equal	find find_if find_if_not (C++11) find_end find_first_of adjacent_find search search_n
シーケンス動作を変更する Original: Modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
copy copy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   (C++11) unique unique_copy
操作を仕切る Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned (C++11) partition partition_copy (C++11)	stable_partition partition_point (C++11)
（ソートされた範囲で）ソート操作 Original: Sorting operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_sorted (C++11) is_sorted_until (C++11) sort	partial_sort partial_sort_copy stable_sort nth_element
バイナリ検索操作（ソート範囲で） Original: Binary search operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lower_bound upper_bound	binary_search equal_range
（ソートされた範囲で）操作を設定します Original: Set operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
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max max_element min min_element minmax (C++11) minmax_element (C++11)	lexicographical_compare is_permutation (C++11) next_permutation prev_permutation
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qsort	bsearch

 

Defined in header <algorithm>
template<class RandomIt > void nth_element( RandomIt first, RandomIt nth, RandomIt last );	(1)
template<class RandomIt, class Compare > void nth_element( RandomIt first, RandomIt nth, RandomIt last, Compare comp );	(2)

部分的にソートされるように昇順で範囲[first, last)範囲内のすべての要素[first, nth)アール範囲[nth, last)に比べて少ない。最初のバージョンは、要素を比較するoperator<使用して、2番目のバージョンは、指定された比較関数compを使用しています。 nth位置に配置要素は、正確に範囲が完全にソートされていた場合、この位置に現れることになる要素です.

Original:

Partially sorts the range [first, last) in ascending order so that all elements in the range [first, nth) are less than those in the range [nth, last). The first version uses operator< to compare the elements, the second version uses the given comparison function comp. The element placed in the nth position is exactly the element that would occur in this position if the range was fully sorted.

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パラメータ

first, last	-	範囲のソートを定義するランダムアクセス反復子 Original: random access iterators defining the range sort The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
nth	-	ソート·パーティション·ポイントを定義するランダムアクセス反復子を返します Original: random access iterator defining the sort partition point The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
comp	-	比較関数. 最初の値が二つ目の値より小さい 場合、 ​trueを返します. 比較関数のシグネチャは以下と同等でなければなりません.  bool cmp(const Type1 &a, const Type2 &b); シグネチャはconstを含まなくても構いませんが, 比較関数は渡されたオブジェクトを変更してはなりません. The types Type1 and Type2 must be such that an object of type RandomIt can be dereferenced and then implicitly converted to both of them. ​
型の要件
- RandomIt は ValueSwappable and RandomAccessIterator。
- The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible.

値を返します

(なし)

複雑性

平均でstd::distance(first, last)におけるリニア.

Original:

Linear in std::distance(first, last) on average.

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例

このコードを実行します

#include <iostream>#include <vector>#include <algorithm>#include <functional>   int main(){std::vector<int> v{5, 6, 4, 3, 2, 6, 7, 9, 3};   std::nth_element(v.begin(), v.begin()+ v.size()/2, v.end());std::cout<<"The median is "<< v[v.size()/2]<<'\n';   std::nth_element(v.begin(), v.begin()+1, v.end(), std::greater<int>());std::cout<<"The second largest element is "<< v[1]<<'\n';}

出力:

The median is 5 The second largest element is 7

参照

partial_sort_copy	コピーと部分的にソートする要素の範囲 Original: copies and partially sorts a range of elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート)
stable_sort	ソートされた範囲の要素を等しい要素間の順序を維持しながら Original: sorts a range of elements while preserving order between equal elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート)
sort	昇順にソートする範囲 Original: sorts a range into ascending order The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート)