std::is_heap

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Defined in header <algorithm>

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template< class RandomAccessIterator >
bool is_heap( RandomAccessIterator first, RandomAccessIterator last );

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template< class RandomAccessIterator, class Compare >
bool is_heap( RandomAccessIterator first, RandomAccessIterator last, Compare comp );

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Checks if the elements in range [first, last) is a heap. The first version of the function uses Template:cpp to compare the elements, the second uses the given comparison function comp.

first, last	-	the range of elements to examine
comp	-	comparison function object (i.e. an object that satisfies the requirements of Compare) 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); While the signature does not need to have const&, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) Type1 and Type2 regardless of value category (thus, Type1& is not allowed, nor is Type1 unless for Type1 a move is equivalent to a copy(since C++11)). The types Type1 and Type2 must be such that an object of type RandomAccessIterator can be dereferenced and then implicitly converted to both of them.

Template:returns Template:cpp if the range is heap, Template:cpp otherwise.

linear in the distance between first and last

Template:example cpp

Template:notes A heap with respect to comp (max heap) is a random access range [first, last) that has the following properties:

• Given \(\scriptsize N\)N as last - first, for all integer i where \(\scriptsize 0 < i < N\)0 < i < N, bool(comp(first[(i - 1) / 2], first[i])) is false.
• A new element can be added using std::push_heap, in \(\scriptsize \mathcal{O}(\log N)\)𝓞(log N) time.
• *first can be removed using std::pop_heap, in \(\scriptsize \mathcal{O}(\log N)\)𝓞(log N) time.

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