背包 

 1 // 01背包 ==========================================
 2 
 3 memset(f, 0xcf, sizeof(f)); // -INF
 4 f[0][0] = 0;
 5 for (int i = 1; i <= n; i++) {
 6     for (int j = 0; j <= m; j++)
 7         f[i][j] = f[i - 1][j];
 8     for (int j = v[i]; j <= m; j++)
 9         f[i][j] = max(f[i][j], f[i - 1][j - v[i]] + w[i]);
10 }
11 
12 int f[2][MAX_M+1];
13 memset(f, 0xcf, sizeof(f)); // -INF
14 f[0][0] = 0;
15 for (int i = 1; i <= n; i++) {
16     for (int j = 0; j <= m; j++)
17         f[i & 1][j] = f[(i - 1) & 1][j];
18     for (int j = v[i]; j <= m; j++)
19         f[i & 1][j] = max(f[i & 1][j], f[(i - 1) & 1][j - v[i]] + w[i]);
20 }
21 int ans = 0;
22 for (int j = 0; j <= m; j++)
23     ans = max(ans, f[n & 1][j]);
24 
25 int f[MAX_M+1];
26 memset(f, 0xcf, sizeof(f)); // -INF
27 f[0] = 0;
28 for (int i = 1; i <= n; i++)
29     for (int j = m; j >= v[i]; j--)
30         f[j] = max(f[j], f[j - v[i]] + w[i]);
31 int ans = 0;
32 for (int j = 0; j <= m; j++)
33     ans = max(ans, f[j]);
34 
35 
36 // 完全背包 ==========================================
37 
38 int f[MAX_M+1];
39 memset(f, 0xcf, sizeof(f)); // -INF
40 f[0] = 0;
41 for (int i = 1; i <= n; i++)
42     for (int j = v[i]; j <= m; j--)
43         f[j] = max(f[j], f[j - v[i]] + w[i]);
44 int ans = 0;
45 for (int j = 0; j <= m; j++)
46     ans = max(ans, f[j]);
47 
48 
49 // 多重背包，直接拆分 ==========================================
50 
51 unsigned int f[MAX_M+1];
52 memset(f, 0xcf, sizeof(f)); // -INF
53 f[0] = 0;
54 for (int i = 1; i <= n; i++)
55     for (int j = 1; j <= c[i]; j++)
56         for (int k = m; k >= v[i]; k--)
57             f[k] = max(f[k], f[k - v[i]] + w[i]);
58 int ans = 0;
59 for (int i = 0; i <= m; i++)
60     ans = max(ans, f[i]);
61 
62 // 分组背包 ==========================================
63 
64 memset(f, 0xcf, sizeof(f));
65 f[0] = 0;
66 for (int i = 1; i <= n; i++)
67     for (int j = m; j >= 0; j--)
68         for (int k = 1; k <= c[i]; k++)
69             if (j >= v[i][k])
70                 f[j] = max(f[j], f[j - v[i][k]] + w[i][k]);

 

posted @ 2019-04-05 21:49  universeplayer  阅读(143)  评论(0)    收藏  举报