std::make_heap
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在头文件 <algorithm> 中定义
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template< class RandomIt > void make_heap( RandomIt first, RandomIt last ); |
(1) | |
template< class RandomIt, class Compare > void make_heap( RandomIt first, RandomIt last, |
(2) | |
构造一个“堆”的范围内
[first, last)
。 operator<的第一个版本的功能使用比较的元素,第二个使用给定的比较函数comp
.原文:
Constructs a heap in the range
[first, last)
. The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp
.目录 |
[编辑] 参数
first, last | - | 范围内的元素,使堆
原文: the range of elements to make the heap from |
comp | - | comparison function 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); The signature does not need to have const &, but the function must not modify the objects passed to it. |
类型要求 | ||
-RandomIt 必须满足 RandomAccessIterator 的要求。
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-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible .
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[编辑] 返回值
(无)
[编辑] 复杂度
在大多数3*std::distance(first, last)比较.
原文:
At most 3*std::distance(first, last) comparisons.
[编辑] 注释
A“堆”是一个范围的元素
[f,l)
具有以下属性:原文:
A heap is a range of elements
[f,l)
that has the following properties:- *f范围中的最大元素原文:*f is the largest element in the range
- 可以添加一个新的元素,使用std::push_heap()原文:a new element can be added using std::push_heap()
- 使用std::pop_heap()的第一个元素可以被删除原文:the first element can be removed using std::pop_heap()
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实际配置是实现定义的元素.
原文:
The actual arrangement of the elements is implementation defined.
[编辑] 示例
#include <iostream> #include <algorithm> int main() { std::vector<int> v { 3, 1, 4, 1, 5, 9 }; std::cout << "initially, v: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; std::make_heap(v.begin(), v.end()); std::cout << "after make_heap, v: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; std::pop_heap(v.begin(), v.end()); auto largest = v.back(); v.pop_back(); std::cout << "largest element: " << largest << '\n'; std::cout << "after removing the largest element, v: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; }
输出:
initially, v: 3 1 4 1 5 9 after make_heap, v: 9 5 4 1 1 3 largest element: 9 after removing the largest element, v: 5 3 4 1 1
[编辑] 另请参阅
将堆变成一个排好序的区间 (函数模板) |