对满足条件的发票做一遍\(01\)背包即可。

const int N = 3e6 + 10;
int f[N];
int n;
double m;

void update(int v)
{
    for(int j = m; j >= v; j--)
        f[j] = max(f[j], f[j - v] + v);
}

int main()
{
    while(cin >> m >> n && n)
    {
        memset(f, 0 ,sizeof f);
        m *= 100;

        for(int i = 1; i <= n; i++)
        {
            int k;
            cin >> k;
            int sum = 0;
            bool ok = true;
            int v[3] = {0};
            while(k--)
            {
                char c;
                double value;
                scanf(" %c:%lf", &c, &value);
                value *= 100;
                if(c != ‘A‘ && c != ‘B‘ && c != ‘C‘) ok = false;
                else v[c - ‘A‘] += value;

                sum += value;
                if(v[c - ‘A‘] > 60000 || sum > 100000) ok = false;
            }
            if(ok) update(sum);
        }

        printf("%.2f\n", f[int(m)] / 100.0);
    }
    //system("pause");
    return 0;
}

HDU 1864 最大报销额