最优装载问题

/*
   最优装载问题：
   有 n 个集装箱，重量分别为 w[0], ..., w[n - 1] 和一个载重量为
   capacity 的货船，现在要把货船尽可能的装满．

   */

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

class maxLoading
{
    private:
        size_t n; //貨物个数
        size_t capacity; //貨船的載重量
        std::vector<size_t> weight; 
        size_t bestW;
        size_t currentW;
        std::vector<size_t> bestPlan;
        std::vector<size_t> currentPlan;
    public:
        template<class Iter>
        maxLoading(Iter beg, Iter end, size_t _capacity):
            n(end - beg), capacity(_capacity),
            bestW(0), currentW(0), weight(beg, end),
            bestPlan(end - beg, 0), currentPlan(end - beg, 0)
        {
            backtrack(0);
        }

        void output()
        {
            cout << "最优装载重量:" << bestW << '\n';
            cout << "装载货物:" << '\n';
            for(int i = 0; i < n; ++i)
                if(bestPlan[i] == 1)
                    cout << i << ',';
            cout << endl;
        }


    private:
        void backtrack(size_t i)
        {
            if(i == n)
            {
                if(bestW < currentW)
                {
                    bestW = currentW;
                    bestPlan = currentPlan;
                }
            }
            else
            {
                //搜索左子树
                if(currentW + weight[i] <=  capacity)
                {
                    currentPlan[i] = 1;
                    currentW += weight[i];
                    backtrack(i + 1);
                    currentPlan[i] = 0;
                    currentW -=  weight[i];
                }
                backtrack(i + 1);
            }
        }
};

int main()
{
    int a[] = {10, 40, 40};
    maxLoading m(a + 0, a + 3, 80);
    m.output();
}