How do you initialize a map that has a priority_queue as a value with the comparison object of the priority_queue?
By : user2732082
Date : March 29 2020, 07:55 AM
Hope that helps What is "compare"? If it's a function pointer, you must be very careful to not use it before you supply a value, as the default constructed priority_queue will use a null pointer. The easiest way to ensure non-null pointers – if you cannot rewrite or wrap as shown below – is, ironically, to never use the index operator; instead use the find and insert methods. If "compare" is instead a functor, then it should be written so its default construction does exactly what's needed (often nothing) – it is very rare for this to not be possible. code :
bool my_compare(object_t *a, object_t *b) {
// do something
}
typedef bool (*compare)(object_t*, object_t*);
struct compare {
bool operator()(object_t *a, object_t *b) {
// do something
}
};
bool my_compare(object_t*, object_t*);
struct compare {
bool operator()(object_t *a, object_t *b) {
return my_compare(a, b);
}
};
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Comparator for boost::heap::priority_queue vs std::priority_queue
By : Michael
Date : March 29 2020, 07:55 AM
should help you out Yes, the option interface is somewhat under-documented. You specify options like this: code :
boost::heap::priority_queue<Edge, boost::heap::compare<EdgeCompare>>
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How can I make a collection which behaves like the Session[] collection? C#
By : Peter Groot
Date : March 29 2020, 07:55 AM
With these it helps As you have created your own indexer, you want to call the old indexer in your own code. Replace this[key] by base[key] in your code.
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error: could not convert ‘minHeap’ from ‘std::priority_queue, std::greater >’ to ‘std::priority_queue
By : MGupta
Date : March 29 2020, 07:55 AM
wish helps you Your are trying to pass variable with priority_queue, greater > type, but your function expects priority_queue type. Correct the prototype of function:
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"error: no matching function for call to 'std::priority_queue<int>::priority_queue(int)' priority_queue<in
By : pg1024
Date : October 02 2020, 10:00 AM
hope this fix your issue related questionstd::priority_queue doesn't have such constructor, but the below code implements what you want: code :
std::vector<int> temporary_container(4);
std::priority_queue<int, std::vector<int>> pqueue (comparator, std::move(container));
std::vector<int> temporary_container;
temporary_container.reserve(4);
std::priority_queue<int, std::vector<int>> pqueue (comparator, std::move(container));
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