正常二维dp

#include<bits/stdc++.h>
using namespace std;
const int N = 1117;
int f[N][N], n, V, v[N], w[N];
int main()
{
    cin >> n >> V;
    for(int i = 1; i <= n; i ++)cin >> v[i] >> w[i];
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= V; j ++)
            f[i][j] = max(f[i-1][j], (f[i-1][j-v[i]] + w[i]) * (j >= v[i]));
    cout << f[n][V];
}

边输入边处理

#include<bits/stdc++.h>
using namespace std;
const int N = 1117;
int f[N][N], n, V, v, w;
int main()
{
    cin >> n >> V;
    for(int i = 1; i <= n; i ++)
    {
        cin >> v >> w;
        for(int j = 1; j <= V; j ++)
            f[i][j] = max(f[i-1][j], (f[i-1][j-v] + w) * (j >= v));
    }
    cout << f[n][V];
}

滚动数组

#include<bits/stdc++.h>
using namespace std;
const int N = 1117;
int f[2][N], n, V, v, w, t;
int main()
{
    cin >> n >> V;
    for(int i = 1; i <= n; i ++)
    {
        cin >> v >> w;
        for(int j = 1; j <= V; j ++)
            f[t][j] = max(f[t^1][j], (f[t^1][j-v] + w) * (j >= v));
        t ^= 1;
    }
    cout << f[t^1][V];
}

一维数组没有滚动数组好理解，不好debug并且优化不多，建议写到滚动数组结束