Database.h

#pragma once
#include "date.h"
#include "node.h"
#include <string>
#include <ostream>
#include <vector>
#include <map>
#include <set>
#include <memory>
#include<algorithm>
#include "node.h"
#include<iterator>

class Database {
public:
    Database() = default;
    void Add(const Date& date, const std::string& event);
    void Print(std::ostream& is);

    template<typename pred >
    int RemoveIf(pred func) {

        auto it = std::stable_partition(begin(base_vector), end(base_vector),
            [func](const std::pair<Date, std::string>& a) {
                if (func(a.first, a.second))return false;
                else { return true; }
            });
        int t = end(base_vector) - it;
        base_vector.erase(it, end(base_vector));
        return t;
    }
    template<typename pred >
    std::vector<std::pair<Date, std::string>> FindIf(pred func) {
        std::vector<std::pair<Date, std::string>> r;
        auto it = std::remove_copy_if(begin(base_vector), end(base_vector), back_inserter(r),
            [func](const std::pair<Date, std::string>& a) {
                if (func(a.first, a.second))return false;
                else return true;
            });
        return r;
    }
    std::string Last(const Date& a);
private:

    std::vector<std::pair<Date, std::string>> base_vector;
    std::map<Date, std::set<std::string>> base_map;
};
std::ostream& operator << (std::ostream& stream, const std::pair<Date, std::string>& a);