std::binary_search
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Defined in header <algorithm>
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template< class ForwardIt, class T > bool binary_search( ForwardIt first, ForwardIt last, const T& value ); |
(1) | |
template< class ForwardIt, class T, class Compare > bool binary_search( ForwardIt first, ForwardIt last, const T& value, Compare comp ); |
(2) | |
ソート範囲
[first, last)
いるかどうかをチェックvalue
に等しい要素が含まれています。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.Original:
Checks if the sorted range
[first, last)
contains an element equal to value
. The first version uses operator< to compare the elements, the second version uses the given comparison function comp
.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
目次 |
[編集] パラメータ
first, last | - | 検討する要素の範囲
Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
value | - | に要素を比較する値
Original: value to compare the elements to The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
comp | - | comparison function which returns true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. |
Type requirements | ||
-ForwardIt must meet the requirements of ForwardIterator .
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[編集] 値を返します
true
value
に等しい要素が見つかった場合は、falseその他のとき.Original:
true if an element equal to
value
is found, false otherwise.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
[編集] 複雑
first
last
との間の距離の対数Original:
Logarithmic in the distance between
first
and last
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
[編集] 可能な実装
First version |
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template<class ForwardIt, class T> bool binary_search(ForwardIt first, ForwardIt last, const T& value) { first = std::lower_bound(first, last, value); return (first != last && !(value < *first)); } |
Second version |
template<class ForwardIt, class T, class Compare> bool binary_search(ForwardIt first, ForwardIt last, const T& value, Compare comp) { first = std::lower_bound(first, last, value); return (first != last && !(comp(value, *first)); } |
[編集] 例
#include <iostream> #include <algorithm> #include <vector> int main() { std::vector<int> haystack {1, 3, 4, 5, 9}; std::vector<int> needles {1, 2, 3}; for (auto needle : needles) { std::cout << "Searching for " << needle << '\n'; if (std::binary_search(haystack.begin(), haystack.end(), needle)) { std::cout << "Found " << needle << '\n'; } else { std::cout << "no dice!\n"; } } }
Output:
Searching for 1 Found 1 Searching for 2 no dice! Searching for 3 Found 3
[編集] も参照してください
特定のキーと一致する要素の範囲を返します Original: returns range of elements matching a specific key 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) |