我正在使用 Fibonacci heap(boost) 对元素数组进行排序,但我无法遍历堆。 代码是这样的:
#include <deque>
#include <boost/heap/fibonacci_heap.hpp>
#include <iostream>
struct MyData {
...
long int id;
...
};
struct MyCompare{
bool operator()(const deque<MyData> &a, const deque<MyData> &b) const
{
return a[a.size()-1].id > b[b.size()-1].id;
}
};
int main()
{ deque<MyData> array1;
deque<MyData> array2;
MyData app;
app.id=15;
array1.push_front(app);
app.id=10;
array1.push_front(app);
app.id=5;
array2.push_front(app);
app.id=2;
array2.push_front(app);
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> > fib_heap;
fib_heap.push(array1);
fib_heap.push(array2);
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator it;
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator beg =fib_heap.begin();
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator end =fib_heap.end();
for (it=beg;it!=end; ++it) {
deque<MyData> elem;
elem =*it;
for (int k=0;k < elem.size();k++)
cout<<" "<<elem[k].id;
cout<<"\n";
}
}
它在“elem = *it”这一行给我这个错误:recursive_tree_iterator 的实例化错误: 递归树迭代器(无效): 适配器类型(0) {}
有什么办法吗?或者使用另一个有序堆而不是 Fibonacci? 非常感谢。
最佳答案
我认为错误是您不能默认构造迭代器。
尝试消除 it
变量的创建并将其移动到 for 循环中:
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator beg =fib_heap.begin();
boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator end =fib_heap.end();
for (boost::heap::fibonacci_heap<deque<MyData>, boost::heap::compare<MyCompare> >::iterator it=beg;it!=end; ++it) {
deque<MyData> elem;
elem =*it;
for (size_t k=0;k < elem.size();k++)
cout<<" "<<elem[k].id;
cout<<"\n";
}
为了按堆顺序迭代,你可以使用:
ordered_iterator ordered_begin(void) const;
ordered_iterator ordered_end(void) const;
此外,我认为使用 auto
关键字会对代码有益:
for (auto it=fib_heap.begin(), end=fib_heap.end();it!=end; ++it) {
deque<MyData> elem;
elem =*it;
for (size_t k=0;k < elem.size();k++)
cout<<" "<<elem[k].id;
cout<<"\n";
}
关于c++ - 如何遍历包含 deque<MyData> 元素的斐波那契堆( boost ),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21110381/