binary_search (1) template<classForwardIt,classT=typenamestd::iterator_traits<ForwardIt>::value_type>boolbinary_search(ForwardIt first, ForwardIt last,constT&value){returnstd::binary_search(first, last, value,std::less{});} binary_search (2) ...
offset);// check if we have the same keyif(binary_search(begin(leaf), end(leaf), key))return1;if(leaf.n == meta.order) {// split when full// new sibling leafleaf_node_tnew_leaf;
which is almost as slow as the linear vector search. The way in which binary search minimizes the number of comparisons really pays off. However the binary list search looks pretty much linear, rather than logarithmic, and is still substantially slower than the binary vector search. Counting nod...
In this article, we are going to see C++ STL function binary_search() which uses the standard binary search algorithm to search an element within a range.
BinaryPred p ); (4) (C++17 起) template< class ForwardIt, class Searcher > ForwardIt search( ForwardIt first, ForwardIt last, const Searcher& searcher ); (5) (C++17 起) (C++20 起为 constexpr) 1-4) 搜索范围 [first, last) 中首次出现元素序列 [s_first, s_last) 的位置。
std::search在头文件<algorithm>中定义,用于查找满足另一个序列的条件(如果未定义此谓词,则等于)的子序列。 它在序列[first1,last1)中搜索由[first2,last2)定义的子序列的第一个匹配项,然后将一个迭代器返回到该匹配项的第一个元素,如果没有找到匹配项,则返回last1。
Binary search(operating on partitioned/sorted ranges): lower_bound Return iterator to lower bound (function template ) upper_bound Return iterator to upper bound (function template ) equal_range
而在传统的C/C++里是没有相应支持的,我们只能:int binary_search(const std::vector<int> &list, int item) { size_t low{0}; size_t high{list.size() - 1}; while (low <= high) { auto mid = (low + high); auto guess = list[mid]; if (guess == item) { return mid; } else ...
Another possible maps implementation would be a sorted vector (insertion sort) and binary search. This would work well for containers which aren't modified often but are queried frequently. I often do this in C asqsortandbsearchare built in. ...
std::optional<int>binary_search(conststd::vector<int>&list,intitem){size_tlow{0};size_thigh{list.size()-1};while(low<=high){automid=(low+high);autoguess=list[mid];if(guess==item){returnmid;}elseif(guess>item){high=mid-1;}else{low=mid+1;}}returnstd::nullopt;} ...