LeetCode-638.大礼包

class Solution {
public:
    int shoppingOffers(vector<int>& price, vector<vector<int>>& special, vector<int>& needs) {
        //商品单个购买，不选择礼包
        int minPrice = 0;
        for (int i = 0; i < needs.size(); ++i) {
            minPrice += needs[i]*price[i];
        }

        //选择礼包
        for(int i = 0; i < needs.size(); i++)
        {
            //每次递归一个礼包
            if(checkValid(special[i], needs))
            {
                vector<int> remainNeeds;
                for(int j = 0; j < needs.size(); j ++)
                {
                    //剩余需求商品
                    remainNeeds.push_back(needs[j] - special[i][j]);
                }
                //当前花费=递归下一层花费+本次礼包花费
                int tempPrice = shoppingOffers(price, special, remainNeeds) + special[i][needs.size()];
                //比较当前花费与直接购买商品花费对比，得到当前递归层最低消费
                minPrice = min(minPrice, tempPrice);
            }
        }
        return minPrice;
    }
    
    bool checkValid(vector<int>& special, vector<int>& needs)
    {
        for(int i = 0; i < needs.size(); i++)
        {
            if(special[i] > needs[i])
            {
                return false;
            }
        }
        return true;
    }
};