【C++】C++ STL探索：Priority Queue与仿函数的深入解析（三）

#pragma once
#include <vector>
#include <algorithm>
namespace bit
{
    class Date
    {
        public:
        friend ostream& operator<<(ostream& _cout, const Date& d);
        Date(int year = 1900, int month = 1, int day = 1)
            : _year(year)
                , _month(month)
                , _day(day)
            {}
        bool operator<(const Date& d)const
        {
            return (_year < d._year) ||
                (_year == d._year && _month < d._month) ||
                (_year == d._year && _month == d._month && _day < d._day);
        }
        bool operator>(const Date& d)const
        {
            return (_year > d._year) ||
                (_year == d._year && _month > d._month) ||
                (_year == d._year && _month == d._month && _day > d._day);
        }
        private:
        int _year;
        int _month;
        int _day;
    };
    ostream& operator<<(ostream& _cout, const Date& d)
    {
        _cout << d._year << "-" << d._month << "-" << d._day;
        return _cout;
    }
    template<class T>
        class Less
        {
            public:
            bool operator()(const T& x, const T& y)
            {
                return x < y;
            }
        };
    template<class T>
        class Greater
        {
            public:
            bool operator()(const T& x, const T& y)
            {
                return x > y;
            }
        };
    template<class T, class Containor = vector<T>, class Compare = Less<T>>
        class priority_queue
        {
            public:
            Compare _com;
            void push(const T& x)
            {
                _con.push_back(x);
                adjust_up(_con.size() - 1);
            }
            void adjust_up(size_t child)
            {
                size_t parent = (child - 1) / 2;
                while (child > 0)
                {
                    //if (_con[parent] < _con[child])
                    if (_com(_con[parent], _con[child]))
                    {
                        std::swap(_con[child], _con[parent]);
                        child = parent;
                        parent = (child - 1) / 2;
                    }
                    else
                        break;
                }
            }
            void pop()
            {
                std::swap(_con[0], _con[_con.size() - 1]);
                _con.pop_back();
                adjust_down(0);
            }
            void adjust_down(size_t parent)
            {
                size_t child = parent * 2 + 1;
                while (child < _con.size())
                {
                    if (child + 1 < _con.size() && _con[child] < _con[child + 1])
                        child++;
                    //if (_con[parent] < _con[child])
                    if (_com(_con[parent], _con[child]))
                    {
                        std::swap(_con[child], _con[parent]);
                        parent = child;
                        child = parent * 2 + 1;
                    }
                    else
                        break;
                }
            }
            const T& top()
            {
                return _con[0];
            }
            size_t size()
            {
                return _con.size();
            }
            bool empty()
            {
                return _con.empty();
            }
            private:
            Containor _con;
        };
    void test1()
    {
        priority_queue<int> pq;
        pq.push(3);
        pq.push(2);
        pq.push(2);
        pq.push(110);
        while (!pq.empty())
        {
            cout << pq.top() << " ";
            pq.pop();
        }
        cout << endl;
    }
    class GteaterDate
    {
        public:
        bool operator()(const Date* p1, const Date* p2)
        {
            return *p1 > *p2;
        }
    };
    void test2()
    {
        priority_queue <Date*, vector<Date*>, GteaterDate> pqptr;
        //priority_queue <Date*, vector<Date*>> pqptr;
        pqptr.push(new Date(2024, 4, 14));
        pqptr.push(new Date(2024, 4, 11));
        pqptr.push(new Date(2024, 4, 15));
        while (!pqptr.empty())
        {
            cout << *(pqptr.top()) << " ";
            pqptr.pop();
        }
        cout << endl;
    }
}