poj2392 Space Elevator

思路：

排序+dp。

实现：

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <cstring>
 5 using namespace std;
 6 
 7 const int INF = 0x3f3f3f3f;
 8 
 9 int K, dp[405][40005];
10 struct node
11 {
12     int h, a, n;
13 };
14 node a[405];
15 
16 bool cmp(const node & x, const node & y)
17 {
18     return x.a < y.a;
19 }
20 
21 int solve()
22 {
23     for (int j = 0; j <= 40000; j++)
24     {
25         dp[K][j] = j;
26     }
27     for (int i = K - 1; i >= 0; i--)
28     {
29         for (int j = 0; j <= 40000; j++)
30         {
31             dp[i][j] = -INF;
32             for (int t = 0; t <= a[i].n; t++)
33             {
34                 if (j + t * a[i].h > a[i].a)
35                     break;
36                 dp[i][j] = max(dp[i][j], dp[i + 1][j + t * a[i].h]);
37             }
38         }
39     }
40     return dp[0][0];
41 }
42 
43 int main()
44 {
45     cin >> K;
46     for (int i = 0; i < K; i++)
47     {
48         cin >> a[i].h >> a[i].a >> a[i].n;
49     }
50     sort(a, a + K, cmp);
51     cout << solve() << endl;
52     return 0;
53 }