pop_heap

从堆的前面移除最大的元素下-在范围中倒数第一个位置然后从窗体其余元素的新的堆。

template<class RandomAccessIterator>
   void pop_heap(
      RandomAccessIterator _First, 
      RandomAccessIterator _Last
   );
template<class RandomAccessIterator, class BinaryPredicate>
   void pop_heap(
      RandomAccessIterator _First, 
      RandomAccessIterator _Last,
      BinaryPredicate _Comp
   );

参数

• _First
  解决一个随机访问迭代器第一个元素的位置在堆。

• _Last
  解决一个随机访问迭代器通过最终元素的位置一在堆。

• _Comp
  定义含义的用户定义的谓词函数对象哪个元素比另一个小于。二进制谓词采用两个参数并返回 true ，在满足和 false，在未满足。

备注

pop_heap 算法是 push_heap 算法执行的操作的反，在下的元素范围中倒数第一个位置添加到包含的元素的堆在范围，在以下情况下，当添加到堆的元素比任何元素已在堆时。

堆具有两个属性:

• 第一个元素始终最大。

• 元素在对数时可以添加或移除。

堆是一个理想方式实现优先级队列，并用于标准模板库(stl)容器适配器 priority_queue选件类的实现。

引用的范围必须是有效的;所有指针必须dereferenceable，并在该序列中最后位置以访问按增量。

除新添加的元素的范围在末尾必须是堆。

复杂是对数的要求，至多记录(_Last – _First)进行比较。

示例

// alg_pop_heap.cpp
// compile with: /EHsc
#include <vector>
#include <algorithm>
#include <functional>
#include <iostream>

int main( )  {
   using namespace std;
   vector <int> v1;
   vector <int>::iterator Iter1, Iter2;

   int i;
   for ( i = 1 ; i <= 9 ; i++ )
      v1.push_back( i );

   // Make v1 a heap with default less than ordering
   random_shuffle( v1.begin( ), v1.end( ) );
   make_heap ( v1.begin( ), v1.end( ) );
   cout << "The heaped version of vector v1 is ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Add an element to the back of the heap
   v1.push_back( 10 );
   push_heap( v1.begin( ), v1.end( ) );
   cout << "The reheaped v1 with 10 added is ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Remove the largest element from the heap
   pop_heap( v1.begin( ), v1.end( ) );
   cout << "The heap v1 with 10 removed is ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl << endl;

   // Make v1 a heap with greater-than ordering with a 0 element
   make_heap ( v1.begin( ), v1.end( ), greater<int>( ) );
   v1.push_back( 0 );
   push_heap( v1.begin( ), v1.end( ), greater<int>( ) );
   cout << "The 'greater than' reheaped v1 puts the smallest "
        << "element first:\n ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Application of pop_heap to remove the smallest element
   pop_heap( v1.begin( ), v1.end( ), greater<int>( ) );
   cout << "The 'greater than' heaped v1 with the smallest element\n "
        << "removed from the heap is: ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;
}

示例输出

The heaped version of vector v1 is ( 9 5 8 4 1 6 7 2 3 ).
The reheaped v1 with 10 added is ( 10 9 8 4 5 6 7 2 3 1 ).
The heap v1 with 10 removed is ( 9 5 8 4 1 6 7 2 3 10 ).

The 'greater than' reheaped v1 puts the smallest element first:
 ( 0 1 6 3 2 8 7 4 9 10 5 ).
The 'greater than' heaped v1 with the smallest element
 removed from the heap is: ( 1 2 6 3 5 8 7 4 9 10 0 ).

要求

标头: <algorithm>

命名空间: std

请参见

参考

heap

标准模板库