也是二进制拆分 可能更简单一些

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 25000;
int f[N];
//int v[20001] = { 0 }, w[20001] = { 0 }, s[1001] = { 0 };

int main(void) {
    int n, m;
    scanf("%d %d", &n, &m);
    memset(f, 0, sizeof(f));
    int v, w, s;

    for (int i = 0; i < n; i++) {
        scanf("%d %d %d", &v, &w, &s);
        int num = min(s, m / v);   //节省1
        for (int k = 1; num > 0; k <<= 1) {  //节省2  <<=是左移操作
            if (k > num)
                k = num;   //注意这里和for循环的结束条件
            num -= k;
            for (int j = m; j >= v * k; j--) {
                f[j] = max(f[j], f[j - v * k] + w * k);
            }
        }

    }
    printf("%d\n", f[m]);
    return 0;
}