堆的操作（make_heap，push_heap,pop_heap,sort_heap,is_heap）

　　堆不是一中sort ranges，堆中的元素不会以递增方式排列，内部以树状形式排列，该结构以每个结点小于等于父节点构成，优先队列就是以堆来实现

make_heap

//版本一：用operator <比较元素 
template <class RandomAccessIterator>
void make_heap(RandomAccessIterator first,RandomAccessIterator last);

//版本二：用自定义的function object比较元素
template <class RandomAccessIterator,class StrictWeakOrdering>
void make_heap(RandomAccessIterator first,RandomAccessIterator last,StrictWeakOrdering cmp);

push_heap

//版本一：用operator <比较元素 
template <class RandomAccessIterator>
void push_heap(RandomAccessIterator first,RandomAccessIterator last);

//版本二：用自定义的function object比较元素
template <class RandomAccessIterator,class StrictWeakOrdering>
void push_heap(RandomAccessIterator first,RandomAccessIterator last,StrictWeakOrdering cmp);

　　堆以[first,last-1)表示，新增加的元素为*(last-1)；[first,last-1)为有效地range，也就是其不为空并且是一个堆

pop_heap

//版本一：用operator <比较元素 
template <class RandomAccessIterator>
void pop_heap(RandomAccessIterator first,RandomAccessIterator last);

//版本二：用自定义的function object比较元素
template <class RandomAccessIterator,class StrictWeakOrdering>
void pop_heap(RandomAccessIterator first,RandomAccessIterator last,StrictWeakOrdering cmp);

　　从堆中移除最大元素（即*first）；[first,last-1)为有效地range，也就是其不为空；这两个版本的操作都有一个必然的结果：从堆中移除的元素是*(last-1)，并且移除后为一个新堆

sort_heap

//版本一：用operator <比较元素 
template <class RandomAccessIterator>
void sort_heap(RandomAccessIterator first,RandomAccessIterator last);

//版本二：用自定义的function object比较元素
template <class RandomAccessIterator,class StrictWeakOrdering>
void sort_heap(RandomAccessIterator first,RandomAccessIterator last,StrictWeakOrdering cmp);

　　把堆转化为一个sorted ranges，不一定会保持等价元素的相对顺序

is_heap

//版本一：用operator <比较元素 
template <class RandomAccessIterator>
void is_heap(RandomAccessIterator first,RandomAccessIterator last);

//版本二：用自定义的function object比较元素
template <class RandomAccessIterator,class StrictWeakOrdering>
void is_heap(RandomAccessIterator first,RandomAccessIterator last,StrictWeakOrdering cmp);

　　测试一个序列是否是一个堆

#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;

int main()
{
    vector<int> v{6,5,9,1,6,3,12};
    make_heap(v.begin(),v.end()-1);
    for_each(v.begin(),v.end(),[](int i)
    {
        cout<<i<<" ";
    });
    cout<<endl;
    
    push_heap(v.begin(),v.end());
    for_each(v.begin(),v.end(),[](int i)
    {
        cout<<i<<" ";
    });
    cout<<endl;
    
    cout<<is_heap(v.begin(),v.end())<<endl;
    
    sort_heap(v.begin(),v.end());
    cout<<is_heap(v.begin(),v.end())<<endl;    
    return 0;
}