std::lower_bound
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ヘッダ <algorithm> で定義 | ||
template<class ForwardIt, class T > ForwardIt lower_bound( ForwardIt first, ForwardIt last, const T& value ); | (1) | |
template<class ForwardIt, class T, class Compare > ForwardIt lower_bound( ForwardIt first, ForwardIt last, const T& value, Compare comp ); | (2) | |
Returns an iterator pointing to the first element in the range [first, last) that is not less than value. The first version uses operator< to compare the elements, the second version uses the given comparison function comp.
目次 |
[編集]パラメータ
| first, last | - | iterators defining the range to examine |
| 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 | - | 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 |
| 型の要件 | ||
-ForwardIt は ForwardIteratorの要求を満足しなければなりません。 | ||
[編集]値を返します
Iterator pointing to the first element that is not less than value, or last if no such element is found.
[編集]複雑性
firstlastとの間の距離の対数first and lastYou can help to correct and verify the translation. Click here for instructions.
[編集]可能な実装
| First version |
|---|
template<class ForwardIt, class T> ForwardIt lower_bound(ForwardIt first, ForwardIt last, const T& value){ ForwardIt it;std::iterator_traits<ForwardIt>::difference_type count, step; count =std::distance(first, last); while(count >0){ it = first; step = count /2;std::advance(it, step);if(*it < value){ first =++it; count -= step +1;}else count = step;}return first;} |
| Second version |
template<class ForwardIt, class T, class Compare> ForwardIt lower_bound(ForwardIt first, ForwardIt last, const T& value, Compare comp){ ForwardIt it;std::iterator_traits<ForwardIt>::difference_type count, step; count =std::distance(first,last); while(count >0){ it = first; step = count /2;std::advance(it, step);if(comp(*it, value)), first =++it; count -= step +1;}else count = step;}return first;} |
[編集]例
#include <algorithm>#include <iostream>#include <iterator>#include <vector> int main(){std::vector<int> data ={1, 1, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 6}; auto lower = std::lower_bound(data.begin(), data.end(), 4);auto upper =std::upper_bound(data.begin(), data.end(), 4); std::copy(lower, upper, std::ostream_iterator<int>(std::cout, " "));}
出力:
4 4 4
[編集]参照
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) | |
最初の要素を指すイテレータを返す特定の値より大きい Original: returns an iterator to the first element greater than a certain value 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) | |
