0-1背包问题——递归与动态规划

#include
using namespace std;

int best_solution(int i,int c,int values[],int  weights[])//i表示拿入几个商品，c表示容量
{
    if (i == 0 || c == 0)return 0;//递归出口
    if (weights[i] > c)return best_solution(i - 1, c, values, weights);//容量太大，舍弃

    //放得下，需要考虑是否放下能得到最大
    int tmp1 = best_solution(i - 1, c, values, weights);//不放
    int tmp2 = best_solution(i - 1, c - weights[i], values, weights) + values[i];
    int result = tmp1>tmp2?tmp1:tmp2;
    return result;
}

void best_solution2(int bestarr[5][11], int values[], int weight[])
{
    for (int i = 0; i < 5; i++){bestarr[i][0] = 0;}
    for (int i = 0; i < 11; i++) { bestarr[0][i] = 0; }
    for (int i = 1; i < 5; i++)
    {
        for (int j = 1; j < 11; j++)
        {
            if (j < weight[i])//容量够
                bestarr[i][j] = bestarr[i - 1][j];
            else
            {
                if (bestarr[i - 1][j] > bestarr[i - 1][j - weight[i]] + values[i])
                {
                    bestarr[i][j] = bestarr[i - 1][j];
                }
                else
                {
                    bestarr[i][j] = bestarr[i - 1][j - weight[i]] + values[i];
                }

            }
        }
    }
}
void print(int best_s[5][11])
{
    for (int i = 0; i < 5; i++) 
    {
        for (int j = 0; j < 11; j++) 
        { 
            cout << "   " << best_s[i][j];
        }
        cout << endl;
    }
}
int main(int* argc, int* argv[])
{
    int values[5] = { 0,2,4,3,7 };
    int weights[5] = { 0,2,3,5,5 };
    int result = best_solution(4,10, values, weights);
    cout << result << endl;

    int best_s[5][11];
    best_solution2(best_s, values, weights);
    print(best_s);
}