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53 lines
1.8 KiB
ReStructuredText
53 lines
1.8 KiB
ReStructuredText
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.. _sprout-algorithm-lower_bound:
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###############################################################################
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lower_bound
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###############################################################################
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Interface
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========================================
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.. sourcecode:: c++
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template<typename ForwardIterator, typename T>
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inline SPROUT_CONSTEXPR ForwardIterator
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lower_bound(ForwardIterator first, ForwardIterator last, T const& value);
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template<typename ForwardIterator, typename T, typename Compare>
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inline SPROUT_CONSTEXPR ForwardIterator
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lower_bound(ForwardIterator first, ForwardIterator last, T const& value, Compare comp);
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Requires
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========================================
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| The elements e of [first,last) shall be partitioned with respect to the expression ``e < value`` or ``comp(e, value)``.
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Returns
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========================================
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| The furthermost iterator i in the range [first,last] such that for any iterator j in the range [first,i) the following corresponding conditions hold: ``*j < value`` or ``comp(*j, value)``.
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Examples
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========================================
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.. sourcecode:: c++
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#include <sprout/algorithm/lower_bound.hpp>
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#include <sprout/array.hpp>
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#include <sprout/container.hpp>
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using namespace sprout;
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SPROUT_STATIC_CONSTEXPR auto input = array<int, 10>{{1, 2, 3, 5, 5, 5, 5, 8, 9, 10}};
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SPROUT_STATIC_CONSTEXPR auto result = sprout::lower_bound(begin(input), end(input), 5);
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static_assert(result - begin(input) == 3, "a lower bound position is 3.");
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Complexity
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========================================
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| At most ``log2(last - first) + O(1)`` comparisons.
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| Recursive function invocations in *O(logN)* (logarithmic) depth.
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Header
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========================================
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| ``sprout/algorithm/lower_bound.hpp``
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| Convenience header: ``sprout/algorithm.hpp``
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