586 lines
21 KiB
C++
586 lines
21 KiB
C++
// This file is part of the uSTL library, an STL implementation.
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//
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// Copyright (c) 2005 by Mike Sharov <msharov@users.sourceforge.net>
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// This file is free software, distributed under the MIT License.
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#pragma once
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#include "ualgo.h"
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namespace ustl {
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/// Copy_if copies elements from the range [first, last) to the range
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/// [result, result + (last - first)) if pred(*i) returns true.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename OutputIterator, typename Predicate>
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inline OutputIterator copy_if (InputIterator first, InputIterator last, OutputIterator result, Predicate pred)
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{
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for (; first != last; ++first) {
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if (pred(*first)) {
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*result = *first;
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++ result;
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}
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}
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return result;
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}
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/// Returns the first iterator i in the range [first, last) such that
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/// pred(*i) is true. Returns last if no such iterator exists.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename Predicate>
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inline InputIterator find_if (InputIterator first, InputIterator last, Predicate pred)
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{
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while (first != last && !pred (*first))
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++ first;
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return first;
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}
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/// Returns the first iterator such that p(*i, *(i + 1)) == true.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename BinaryPredicate>
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inline ForwardIterator adjacent_find (ForwardIterator first, ForwardIterator last, BinaryPredicate p)
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{
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if (first != last)
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for (ForwardIterator prev = first; ++first != last; ++ prev)
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if (p (*prev, *first))
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return prev;
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return last;
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}
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/// Returns the pointer to the first pair of unequal elements.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename BinaryPredicate>
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inline pair<InputIterator,InputIterator>
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mismatch (InputIterator first1, InputIterator last1, InputIterator first2, BinaryPredicate comp)
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{
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while (first1 != last1 && comp(*first1, *first2))
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++ first1, ++ first2;
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return make_pair (first1, first2);
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}
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/// Returns true if two ranges are equal.
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/// This is an extension, present in uSTL and SGI STL.
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/// \ingroup ConditionAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename BinaryPredicate>
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inline bool equal (InputIterator first1, InputIterator last1, InputIterator first2, BinaryPredicate comp)
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{
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return mismatch (first1, last1, first2, comp).first == last1;
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}
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/// Count_if finds the number of elements in [first, last) that satisfy the
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/// predicate pred. More precisely, the first version of count_if returns the
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/// number of iterators i in [first, last) such that pred(*i) is true.
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/// \ingroup ConditionAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename Predicate>
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inline size_t count_if (InputIterator first, InputIterator last, Predicate pred)
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{
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size_t total = 0;
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for (; first != last; ++first)
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if (pred (*first))
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++ total;
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return total;
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}
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/// Replace_if replaces every element in the range [first, last) for which
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/// pred returns true with new_value. That is: for every iterator i, if
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/// pred(*i) is true then it performs the assignment *i = new_value.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename Predicate, typename T>
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inline void replace_if (ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value)
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{
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for (; first != last; ++first)
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if (pred (*first))
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*first = new_value;
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}
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/// Replace_copy_if copies elements from the range [first, last) to the range
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/// [result, result + (last-first)), except that any element for which pred is
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/// true is not copied; new_value is copied instead. More precisely, for every
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/// integer n such that 0 <= n < last-first, replace_copy_if performs the
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/// assignment *(result+n) = new_value if pred(*(first+n)),
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/// and *(result+n) = *(first+n) otherwise.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename OutputIterator, typename Predicate, typename T>
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inline OutputIterator replace_copy_if (InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value)
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{
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for (; first != last; ++result, ++first)
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*result = pred(*first) ? new_value : *first;
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}
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/// Remove_copy_if copies elements from the range [first, last) to a range
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/// beginning at result, except that elements for which pred is true are not
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/// copied. The return value is the end of the resulting range. This operation
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/// is stable, meaning that the relative order of the elements that are copied
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/// is the same as in the range [first, last).
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename OutputIterator, typename Predicate>
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inline OutputIterator remove_copy_if (InputIterator first, InputIterator last, OutputIterator result, Predicate pred)
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{
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for (; first != last; ++first)
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if (!pred (*first))
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*result++ = *first;
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return result;
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}
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/// Remove_if removes from the range [first, last) every element x such that
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/// pred(x) is true. That is, remove_if returns an iterator new_last such that
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/// the range [first, new_last) contains no elements for which pred is true.
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/// The iterators in the range [new_last, last) are all still dereferenceable,
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/// but the elements that they point to are unspecified. Remove_if is stable,
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/// meaning that the relative order of elements that are not removed is
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/// unchanged.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename Predicate>
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inline ForwardIterator remove_if (ForwardIterator first, ForwardIterator last, Predicate pred)
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{
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return remove_copy_if (first, last, first, pred);
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}
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/// The reason there are two different versions of unique_copy is that there
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/// are two different definitions of what it means for a consecutive group of
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/// elements to be duplicates. In the first version, the test is simple
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/// equality: the elements in a range [f, l) are duplicates if, for every
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/// iterator i in the range, either i == f or else *i == *(i-1). In the second,
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/// the test is an arbitrary Binary Predicate binary_pred: the elements in
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/// [f, l) are duplicates if, for every iterator i in the range, either
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/// i == f or else binary_pred(*i, *(i-1)) is true.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename InputIterator, typename OutputIterator, typename BinaryPredicate>
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OutputIterator unique_copy (InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate binary_pred)
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{
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if (first != last) {
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*result = *first;
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while (++first != last)
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if (!binary_pred (*first, *result))
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*++result = *first;
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++ result;
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}
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return result;
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}
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/// Every time a consecutive group of duplicate elements appears in the range
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/// [first, last), the algorithm unique removes all but the first element.
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/// That is, unique returns an iterator new_last such that the range [first,
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/// new_last) contains no two consecutive elements that are duplicates.
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/// The iterators in the range [new_last, last) are all still dereferenceable,
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/// but the elements that they point to are unspecified. Unique is stable,
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/// meaning that the relative order of elements that are not removed is
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/// unchanged.
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/// \ingroup MutatingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename BinaryPredicate>
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inline ForwardIterator unique (ForwardIterator first, ForwardIterator last, BinaryPredicate binary_pred)
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{
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return unique_copy (first, last, first, binary_pred);
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}
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/// Returns the furthermost iterator i in [first, last) such that,
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/// for every iterator j in [first, i), comp(*j, value) is true.
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/// Assumes the range is sorted.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename T, typename StrictWeakOrdering>
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ForwardIterator lower_bound (ForwardIterator first, ForwardIterator last, const T& value, StrictWeakOrdering comp)
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{
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ForwardIterator mid;
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while (first != last) {
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mid = advance (first, size_t(distance (first,last)) / 2);
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if (comp (*mid, value))
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first = mid + 1;
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else
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last = mid;
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}
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return first;
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}
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/// Performs a binary search inside the sorted range.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename T, typename StrictWeakOrdering>
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inline bool binary_search (ForwardIterator first, ForwardIterator last, const T& value, StrictWeakOrdering comp)
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{
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ForwardIterator found = lower_bound (first, last, value, comp);
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return found != last && !comp(*found, value);
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}
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/// Returns the furthermost iterator i in [first,last) such that for
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/// every iterator j in [first,i), comp(value,*j) is false.
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename T, typename StrictWeakOrdering>
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ForwardIterator upper_bound (ForwardIterator first, ForwardIterator last, const T& value, StrictWeakOrdering comp)
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{
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ForwardIterator mid;
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while (first != last) {
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mid = advance (first, size_t(distance (first,last)) / 2);
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if (comp (value, *mid))
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last = mid;
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else
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first = mid + 1;
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}
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return last;
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}
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/// Returns pair<lower_bound,upper_bound>
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename ForwardIterator, typename T, typename StrictWeakOrdering>
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inline pair<ForwardIterator,ForwardIterator> equal_range (ForwardIterator first, ForwardIterator last, const T& value, StrictWeakOrdering comp)
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{
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pair<ForwardIterator,ForwardIterator> rv;
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rv.second = rv.first = lower_bound (first, last, value, comp);
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while (rv.second != last && !comp(value, *(rv.second)))
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++ rv.second;
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return rv;
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}
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/// \brief Puts \p nth element into its sorted position.
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/// In this implementation, the entire array is sorted. The performance difference is
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/// so small and the function use is so rare, there is no need to have code for it.
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/// \ingroup SortingAlgorithms
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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///
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template <typename RandomAccessIterator, typename Compare>
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inline void nth_element (RandomAccessIterator first, RandomAccessIterator, RandomAccessIterator last, Compare comp)
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{
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sort (first, last, comp);
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}
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/// \brief Searches for the first subsequence [first2,last2) in [first1,last1)
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
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ForwardIterator1 search (ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate comp)
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{
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const ForwardIterator1 slast = last1 - distance(first2, last2) + 1;
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for (; first1 < slast; ++first1) {
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ForwardIterator2 i = first2;
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ForwardIterator1 j = first1;
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for (; i != last2 && comp(*j, *i); ++i, ++j) ;
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if (i == last2)
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return first1;
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}
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return last1;
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}
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/// \brief Searches for the last subsequence [first2,last2) in [first1,last1)
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
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ForwardIterator1 find_end (ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate comp)
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{
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ForwardIterator1 s = last1 - distance(first2, last2);
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for (; first1 < s; --s) {
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ForwardIterator2 i = first2, j = s;
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for (; i != last2 && comp(*j, *i); ++i, ++j) ;
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if (i == last2)
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return s;
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}
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return last1;
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}
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/// \brief Searches for the first occurence of \p count \p values in [first, last)
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename Iterator, typename T, typename BinaryPredicate>
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Iterator search_n (Iterator first, Iterator last, size_t count, const T& value, BinaryPredicate comp)
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{
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size_t n = 0;
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for (; first != last; ++first) {
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if (!comp (*first, value))
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n = 0;
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else if (++n == count)
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return first - --n;
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}
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return last;
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}
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/// \brief Searches [first1,last1) for the first occurrence of an element from [first2,last2)
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/// \ingroup SearchingAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator, typename ForwardIterator, typename BinaryPredicate>
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InputIterator find_first_of (InputIterator first1, InputIterator last1, ForwardIterator first2, ForwardIterator last2, BinaryPredicate comp)
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{
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for (; first1 != last1; ++first1)
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for (ForwardIterator i = first2; i != last2; ++i)
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if (comp (*first1, *i))
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return first1;
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return first1;
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}
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/// \brief Returns true if [first2,last2) is a subset of [first1,last1)
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/// \ingroup ConditionAlgorithms
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/// \ingroup SetAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename StrictWeakOrdering>
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bool includes (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, StrictWeakOrdering comp)
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{
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for (; (first1 != last1) & (first2 != last2); ++first1) {
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if (comp (*first2, *first1))
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return false;
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first2 += !comp (*first1, *first2);
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}
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return first2 == last2;
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}
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/// \brief Merges [first1,last1) with [first2,last2)
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///
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/// Result will contain every element that is in either set. If duplicate
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/// elements are present, max(n,m) is placed in the result.
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///
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/// \ingroup SetAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename OutputIterator, typename StrictWeakOrdering>
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OutputIterator set_union (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, OutputIterator result, StrictWeakOrdering comp)
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{
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for (; (first1 != last1) & (first2 != last2); ++result) {
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if (comp (*first2, *first1))
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*result = *first2++;
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else {
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first2 += !comp (*first1, *first2);
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*result = *first1++;
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}
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}
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return copy (first2, last2, copy (first1, last1, result));
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}
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/// \brief Creates a set containing elements shared by the given ranges.
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/// \ingroup SetAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename OutputIterator, typename StrictWeakOrdering>
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OutputIterator set_intersection (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, OutputIterator result, StrictWeakOrdering comp)
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{
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while ((first1 != last1) & (first2 != last2)) {
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bool b1ge2 = !comp (*first1, *first2), b2ge1 = !comp (*first2, *first1);
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if (b1ge2 & b2ge1)
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*result++ = *first1;
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first1 += b2ge1;
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first2 += b1ge2;
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}
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return result;
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}
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/// \brief Removes from [first1,last1) elements present in [first2,last2)
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/// \ingroup SetAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename OutputIterator, typename StrictWeakOrdering>
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OutputIterator set_difference (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, OutputIterator result, StrictWeakOrdering comp)
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{
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while ((first1 != last1) & (first2 != last2)) {
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bool b1ge2 = !comp (*first1, *first2), b2ge1 = !comp (*first2, *first1);
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if (!b1ge2)
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*result++ = *first1;
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first1 += b2ge1;
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first2 += b1ge2;
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}
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return copy (first1, last1, result);
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}
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/// \brief Performs union of sets A-B and B-A.
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/// \ingroup SetAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename OutputIterator, typename StrictWeakOrdering>
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OutputIterator set_symmetric_difference (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, OutputIterator result, StrictWeakOrdering comp)
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{
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while ((first1 != last1) & (first2 != last2)) {
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bool b1l2 = comp (*first1, *first2), b2l1 = comp (*first2, *first1);
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if (b1l2)
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*result++ = *first1;
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else if (b2l1)
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*result++ = *first2;
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first1 += !b2l1;
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first2 += !b1l2;
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}
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return copy (first2, last2, copy (first1, last1, result));
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}
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/// \brief Returns true if the given range is sorted.
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/// \ingroup ConditionAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename ForwardIterator, typename StrictWeakOrdering>
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bool is_sorted (ForwardIterator first, ForwardIterator last, StrictWeakOrdering comp)
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{
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for (ForwardIterator i = first; ++i < last; ++first)
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if (comp (*i, *first))
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return false;
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return true;
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}
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/// \brief Compares two given containers like strcmp compares strings.
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/// \ingroup ConditionAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename InputIterator1, typename InputIterator2, typename BinaryPredicate>
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bool lexicographical_compare (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, BinaryPredicate comp)
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{
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for (; (first1 != last1) & (first2 != last2); ++first1, ++first2) {
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if (comp (*first1, *first2))
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return true;
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if (comp (*first2, *first1))
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return false;
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}
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return (first1 == last1) & (first2 != last2);
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}
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/// \brief Creates the next lexicographical permutation of [first,last).
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/// Returns false if no further permutations can be created.
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/// \ingroup GeneratorAlgorithms
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/// \ingroup PredicateAlgorithms
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template <typename BidirectionalIterator, typename StrictWeakOrdering>
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bool next_permutation (BidirectionalIterator first, BidirectionalIterator last, StrictWeakOrdering comp)
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{
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if (distance (first, last) < 2)
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return false;
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BidirectionalIterator i = last;
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for (--i; i != first; ) {
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--i;
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if (comp (i[0], i[1])) {
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BidirectionalIterator j = last;
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while (!comp (*i, *--j)) ;
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iter_swap (i, j);
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|
reverse (i + 1, last);
|
|
return true;
|
|
}
|
|
}
|
|
reverse (first, last);
|
|
return false;
|
|
}
|
|
|
|
/// \brief Creates the previous lexicographical permutation of [first,last).
|
|
/// Returns false if no further permutations can be created.
|
|
/// \ingroup GeneratorAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename BidirectionalIterator, typename StrictWeakOrdering>
|
|
bool prev_permutation (BidirectionalIterator first, BidirectionalIterator last, StrictWeakOrdering comp)
|
|
{
|
|
if (distance (first, last) < 2)
|
|
return false;
|
|
BidirectionalIterator i = last;
|
|
for (--i; i != first; ) {
|
|
--i;
|
|
if (comp(i[1], i[0])) {
|
|
BidirectionalIterator j = last;
|
|
while (!comp (*--j, *i)) ;
|
|
iter_swap (i, j);
|
|
reverse (i + 1, last);
|
|
return true;
|
|
}
|
|
}
|
|
reverse (first, last);
|
|
return false;
|
|
}
|
|
|
|
/// \brief Returns iterator to the max element in [first,last)
|
|
/// \ingroup SearchingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename ForwardIterator, typename BinaryPredicate>
|
|
inline ForwardIterator max_element (ForwardIterator first, ForwardIterator last, BinaryPredicate comp)
|
|
{
|
|
ForwardIterator result = first;
|
|
for (; first != last; ++first)
|
|
if (comp (*result, *first))
|
|
result = first;
|
|
return result;
|
|
}
|
|
|
|
/// \brief Returns iterator to the min element in [first,last)
|
|
/// \ingroup SearchingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename ForwardIterator, typename BinaryPredicate>
|
|
inline ForwardIterator min_element (ForwardIterator first, ForwardIterator last, BinaryPredicate comp)
|
|
{
|
|
ForwardIterator result = first;
|
|
for (; first != last; ++first)
|
|
if (comp (*first, *result))
|
|
result = first;
|
|
return result;
|
|
}
|
|
|
|
/// \brief Makes [first,middle) a part of the sorted array.
|
|
/// Contents of [middle,last) is undefined. This implementation just calls stable_sort.
|
|
/// \ingroup SortingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename RandomAccessIterator, typename StrictWeakOrdering>
|
|
inline void partial_sort (RandomAccessIterator first, RandomAccessIterator, RandomAccessIterator last, StrictWeakOrdering comp)
|
|
{
|
|
stable_sort (first, last, comp);
|
|
}
|
|
|
|
/// \brief Like partial_sort, but outputs to [result_first,result_last)
|
|
/// \ingroup SortingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename InputIterator, typename RandomAccessIterator, typename StrictWeakOrdering>
|
|
RandomAccessIterator partial_sort_copy (InputIterator first, InputIterator last, RandomAccessIterator result_first, RandomAccessIterator result_last, StrictWeakOrdering comp)
|
|
{
|
|
RandomAccessIterator rend = result_first;
|
|
for (; first != last; ++first) {
|
|
RandomAccessIterator i = result_first;
|
|
for (; i != rend && comp (*i, *first); ++i) ;
|
|
if (i == result_last)
|
|
continue;
|
|
rend += (rend < result_last);
|
|
copy_backward (i, rend - 1, rend);
|
|
*i = *first;
|
|
}
|
|
return rend;
|
|
}
|
|
|
|
/// \brief Like partition, but preserves equal element order.
|
|
/// \ingroup SortingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename ForwardIterator, typename Predicate>
|
|
ForwardIterator stable_partition (ForwardIterator first, ForwardIterator last, Predicate pred)
|
|
{
|
|
if (first == last)
|
|
return first;
|
|
ForwardIterator l, r, m = advance (first, distance (first, last) / 2);
|
|
if (first == m)
|
|
return pred(*first) ? last : first;
|
|
l = stable_partition (first, m, pred);
|
|
r = stable_partition (m, last, pred);
|
|
rotate (l, m, r);
|
|
return advance (l, distance (m, r));
|
|
}
|
|
|
|
/// \brief Splits [first,last) in two by \p pred.
|
|
///
|
|
/// Creates two ranges [first,middle) and [middle,last), where every element
|
|
/// in the former is less than every element in the latter.
|
|
/// The return value is middle.
|
|
///
|
|
/// \ingroup SortingAlgorithms
|
|
/// \ingroup PredicateAlgorithms
|
|
template <typename ForwardIterator, typename Predicate>
|
|
inline ForwardIterator partition (ForwardIterator first, ForwardIterator last, Predicate pred)
|
|
{
|
|
return stable_partition (first, last, pred);
|
|
}
|
|
|
|
} // namespace ustl
|