lightoj 1011 Marriage Ceremonies (暴力)(记忆化dp,状压) 转

转载自：http://blog.csdn.net/xindoo/article/details/9173949

暴力TLE

 1 #include <iostream>
 2 #include <string.h>
 3 #include <algorithm>
 4
 5 using namespace std;
 6
 7 int vis[17];
 8 int n, ans, sum;
 9 int map[19][19];
10
11 void dfs(int x)
12 {
13     if (x == n+1)
14     {
15         ans = max(ans, sum);
16         return;
17     }
18     for (int i = 1; i <= n; i++)
19     {
20         if (vis[i] == 0)
21         {
22             sum += map[x][i];
23             vis[i] = 1;
24             dfs(x+1);
25             vis[i] = 0;
26             sum -= map[x][i];
27         }
28     }
29 }
30 int main()
31 {
32     int t;
33     cin >> t;
34     for (int kase = 1; kase <= t; kase++)
35     {
36         cin >> n;
37         for (int i = 1; i <= n; i++)
38             for (int j = 1; j <= n; j++)
39                 cin >> map[i][j];
40         sum = 0;
41         ans = 0;
42         memset(vis, 0, sizeof(vis));
43         dfs(1);
44         cout << "Case " << kase << ": " << ans << endl;
45     }
46     return 0;
47 }

状态压缩+dp

//2013-06-25-22.05
#include <iostream>
#include <string.h>
#include <algorithm>
#include <stdio.h>

using namespace std;
const int maxn = 1<<16;
int vis[17];
int n, ans, sum;
int map[19][19];
int dp[maxn];
int dfs(int x, int d)
{
    if (x == 0)
        return 0;
    if (dp[x])
        return dp[x];
    for (int i = 0; i < n; i++)
    {
        if (x&(1<<i))
            dp[x] = max(dfs(x^(1<<i), d-1)+map[i+1][d], dp[x]);
    }
    return dp[x];
}
int main()
{
    int t;
    cin >> t;
    for (int kase = 1; kase <= t; kase++)
    {
        cin >> n;
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
                cin >> map[i][j];
        memset(dp, 0, sizeof(dp));
        ans = dfs((1<<n)-1, n);
        printf("Case %d: %d\n", kase, ans);
    }
    return 0;
}