Test.cpp
#include <iostream>
#include <queue>
#include <functional>
using namespace std;
#include "Priority_queue.h"
void test_priority_queue()
{
jpc::priority_queue<int> pq;
pq.push(3);
pq.push(1);
pq.push(2);
pq.push(5);
pq.push(0);
pq.push(1);
while (!pq.empty())
{
cout << pq.top() << " ";
pq.pop();
}
cout << endl;
int a[] = {3,2,7,6,0,4,1,9,8,5};
jpc::priority_queue<int,vector<int>,greater<int>> heap(a, a + sizeof(a) / sizeof(int));
while (!heap.empty())
{
cout<< heap.top() <<" ";
heap.pop();
}
cout << endl;
}
int main()
{
test_priority_queue();
return 0;
}
Priority_queue.h
#pragma once
namespace jpc
{
template<class T,class Container = vector<T>,class Compare=std::less<T>>
class priority_queue
{
public:
template<class InputIterator>
priority_queue(InputIterator first, InputIterator last)
{
while (first != last)
{
_con.push_back(*first);
++first;
}
for (int i = (_con.size() - 1 - 1) / 2; i >= 0; --i)
{
adjust_down(i);
}
}
priority_queue()
{}
void adjust_up(size_t child)
{
Compare com;
size_t parent = (child-1) / 2;
while (child>0)
{
if(com(_con[parent],_con[child]))
{
std::swap(_con[child],_con[parent]);
child = parent;
parent = (child-1) / 2;
}
else
{
break;
}
}
}
void adjust_down(size_t parent)
{
Compare com;
size_t child = parent * 2 + 1;
while (child<_con.size())
{
if (child + 1 < _con.size() && com(_con[child],_con[child + 1]))
{
++child;
}
if (com(_con[parent],_con[child]))
{
std::swap(_con[child],_con[parent]);
parent = child;
child = parent * 2 + 1;
}
else
{
break;
}
}
}
void push(const T& x)
{
_con.push_back(x);
adjust_up(_con.size()-1);
}
void pop()
{
std::swap(_con[0],_con[_con.size()-1]);
_con.pop_back();
adjust_down(0);
}
const T& top()
{
return _con[0];
}
bool empty() const
{
return _con.empty();
}
size_t size() const
{
return _con.size();
}
private:
Container _con;
};
}