感觉思路没问题，应该是细节，但是没调出来

#include<bits/stdc++.h>
// #define int long long

using namespace std;

template <typename T>
void read(T &x)
{
    T f = 1,res = 0;
    char ch = getchar();
    while(!isdigit(ch)){if(ch == '-') f = -1;ch = getchar();}
    while(isdigit(ch)){res = (res << 1) + (res << 3) + (ch ^ 48);ch = getchar();}
    x = res * f;
}

const int MAXN = 5e3 + 10,inf = 0x3f3f3f3f;
int K,V,n,valx[MAXN],valy[MAXN],dp[MAXN][MAXN],v[MAXN],w[MAXN];

signed main()
{
    read(K),read(V),read(n);
    for(int i = 1;i <= n;i ++)
        read(v[i]),read(w[i]);
    for(int i = 1;i <= n;i ++)
    {
        for(int j = V;j >= v[i];j --)
        {
            for(int k = 1;k <= K;k ++)
            {
                valx[k] = dp[k][j - v[i]] + w[i];
                valy[k] = dp[k][j];
            }
            valx[K + 1] = -inf,valy[K + 1] = -inf;
            int posx = 1,posy = 1,pos = 1;
            while(pos <= K && (valx[posx] != -inf || valy[posy] != -inf))
            {
                if(valx[posx] > valy[posy])
                    dp[pos][j] = valx[posx ++];
                else
                    dp[pos][j] = valy[posy ++];
                if(dp[pos][j] != dp[pos - 1][j]) pos ++;
            }
        }
    }
    int Answer = 0;
    for(int i = 1;i <= K;i ++)
        Answer += dp[i][V];
    printf("%d\n",Answer);
    return 0;
}