AcWing 734. 能量石（贪心排序+01背包）

思虑

1. 对能量石排序
   

2. 排完序用 01 背包求解。

代码

#include <bits/stdc++.h>
using namespace std;
#define db  double
#define ll  long long
#define Pir pair<int, int>
#define fi  first
#define se  second
#define pb  push_back
#define m_p make_pair
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
/*==========ACMer===========*/
const int N = 1e4 + 10;
struct Stone
{
    
    
    int s, e, l;
    bool operator < (const Stone & tmp) const
    {
    
    
        return s * tmp.l < tmp.s * l;
    }
} stone[N];
int f[N];


int main()
{
    
    
    int T, cas = 1; scanf("%d", &T);
    while (T --)
    {
    
    
        int n, m = 0;
        scanf("%d", &n);
        int u, v, w;
        for (int i = 1; i <= n; i ++) {
    
    
            scanf("%d %d %d", &u, &v, &w);
            stone[i] = Stone{
    
     u, v, w };
            m += u;
        }
        sort(stone + 1, stone + 1 + n);

        memset(f, -inf, sizeof f);
        f[0] = 0;
        for (int i = 1; i <= n; i ++) {
    
    
            for (int j = m; j >= stone[i].s; j --) {
    
    
                if (stone[i].e - stone[i].l * (j - stone[i].s) > 0)
                    f[j] = max(f[j], f[j - stone[i].s] + stone[i].e - stone[i].l * (j - stone[i].s));
            }
        }

        int ans = 0;
        for (int i = 1; i <= m; i ++) ans = max(ans, f[i]);
        printf("Case #%d: %d\n", cas ++, ans);
    }


    return 0;
}