boost::range::pop_heap
References
Headers
boost::range::pop_heap
is available by including
any of the following headers:
boost/range/algorithm/heap_algorithm.hpp
orboost/range/algorithm.hpp
Examples
heap.cpp
#include <functional>
#include <iostream>
#include <boost/range/algorithm.hpp>
void display(const std::string &caption, const std::vector<int> vec) {
std::cout << caption;
boost::copy(vec, std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
}
int main() {
std::vector<int> vec = {1, 3, 9, 4, 16, 7};
// make_heap() turns the input range to a heap. By default, a max-heap
// is created, but this can be overridden by passing a different ordering
// predicate.
// Returns a reference to the input range.
boost::range::make_heap(vec);
display("Initial heap: ", vec);
// pop_heap() rearranges the input range so that [0, end-1) is a new
// max-heap and rng[end-1] holds the previous max element.
// Removal of elements from the heap always consists of this
// pop_heap()/pop_back() cascade.
// Returns a reference to the input range.
boost::range::pop_heap(vec);
vec.pop_back();
display("Heap after pop_heap(): ", vec);
// push_heap() takes the element at rng[end-1] and inserts it into a
// pre-existing heap in [0, end-1). Heap insertion always consists
// of this push_back/push_heap cascade.
// Returns a reference to the input range.
vec.push_back(32);
boost::range::push_heap(vec);
display("Heap after push_heap(): ", vec);
// sort_heap() sorts a pre-existing heap in the input range.
// This destroys the heap properties.
boost::range::sort_heap(vec);
display("Heap after sorting: ", vec);
return 0;
}
Output:
Initial heap: 16 4 9 1 3 7
Heap after pop_heap(): 9 4 7 1 3
Heap after push_heap(): 32 4 9 1 3 7
Heap after sorting: 1 3 4 7 9 32
heap_with_predicate.cpp
#include <functional>
#include <iostream>
#include <boost/range/algorithm.hpp>
void display(const std::string &caption, const std::vector<int> vec) {
std::cout << caption;
boost::copy(vec, std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
}
int main() {
std::vector<int> vec = {1, 3, 9, 4, 16, 7};
// make_heap() turns the input range to a heap. By default, a max-heap
// is created, but this can be overridden by passing a different ordering
// predicate. In this case, a min-heap is generated.
// Returns a reference to the input range.
boost::range::make_heap(vec, std::greater<int>());
display("Initial heap: ", vec);
// pop_heap() rearranges the input range so that [0, end-1) is a new
// heap and rng[end-1] holds the previous top element.
// Removal of elements from the heap always consists of this
// pop_heap()/pop_back() cascade.
// Returns a reference to the input range.
boost::range::pop_heap(vec, std::greater<int>());
vec.pop_back();
display("Heap after pop_heap(): ", vec);
// push_heap() takes the element at rng[end-1] and inserts it into a
// pre-existing heap in [0, end-1). Heap insertion always consists
// of this push_back/push_heap cascade.
// Returns a reference to the input range.
vec.push_back(32);
boost::range::push_heap(vec, std::greater<int>());
display("Heap after push_heap(): ", vec);
// sort_heap() sorts a pre-existing heap in the input range.
// This destroys the heap properties.
boost::range::sort_heap(vec, std::greater<int>());
display("Heap after sorting: ", vec);
return 0;
}
Output:
Initial heap: 1 3 7 4 16 9
Heap after pop_heap(): 3 4 7 9 16
Heap after push_heap(): 3 4 7 9 16 32
Heap after sorting: 32 16 9 7 4 3
Boost Range for Humans
This reference is part of Boost Range for Humans. Click the link to the overview.