"Algorithm learning" old algorithm, new posture, stl--heap

A "heap" is a familiar data structure that maintains the set's extrema within the time of \ (O (log\;n) \).

This is the old routine, the specific internal implementation I will not talk about.

I generally use the priority_queue in the queue library, which is the STL's priority queue, to implement the heap, but recently I found a new STL container with smaller constants and more convenient operations relative to the priority queue.

It's the heap.

About HEAP,STL provides 4 functions that are defined in the algorithm library. Each of them is:

Like sort , where _first,_last are heads, tail pointers or iterators (corresponding to vectors or queue), and _cmp represents the size relationship function between elements.

Similar to sort, the element in the heap is an interval of [_first, _last], if memory is not contiguous, or at least a randomly accessible iterator (such as a vector).

Where _cmp are not necessary.

It is also important to note that these functions are maintained by Dagen (that is, the father value is larger than the child's heap, also known as the largest heap).

Build heap:

Make_heap (_first, _last, _cmp)

To add elements to the heap:

Push_heap (_first, _last, _cmp)

To add an element first, call the function again.

To delete an element in the heap:

Pop_heap (_first, _last, _cmp)

To call the function first, then delete (do not delete, as long as the guarantee that there will be no memory leaks or other bugs).

Heap Sort:

Sort_heap (_first, _last, _cmp)

The sequence, like the normal sort, becomes an ordered array. No longer has the nature of the heap.

Boom, the code will be pasted later.

"Algorithm learning" old algorithm, new posture, stl--heap