【分组背包问题】AcWing9.分组背包问题

AcWing9.分组背包问题

题解

一维状压

#include <iostream>

using namespace std;

const int N = 110;

int n, m, s[N], v[N][N], w[N][N], f[N];

int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
    {
        cin >> s[i];
        for(int j = 1; j <= s[i]; ++j)
            cin >> v[i][j] >> w[i][j];
    }
    for(int i = 1; i <= n; ++i)
        for(int j = m; j >= 0; --j)
        {
            for(int k = 0; k <= s[i]; ++k)
             if(j >= v[i][k]) f[j] = max(f[j], f[j- v[i][k] ] + w[i][k]);   
        }
    cout << f[m] << endl;
    return 0;
}

二维

#include <iostream>

using namespace std;

const int N = 110;

int n, m, s[N], v[N][N], w[N][N], f[N][N];

int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
    {
        cin >> s[i];
        for(int j = 1; j <= s[i]; ++j)
            cin >> v[i][j] >> w[i][j];
    }
    for(int i = 1; i <= n; ++i)
        for(int j = 0; j <= m; ++j)
        {
            for(int k = 0; k <= s[i]; ++k)
                if(j >= v[i][k]) f[i][j] = max(f[i][j], f[i-1][j - v[i][k]] +  w[i][k]);
        }
    cout << f[n][m] << endl;
    return 0;
}