HDU 3488 KM Tour

参考题解

这题注意有重边。。

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 const int maxn = 200 + 10;
 7 
 8 int n, m;
 9 int W[maxn][maxn], lft[maxn];
10 int Lx[maxn], Ly[maxn];
11 bool S[maxn], T[maxn];
12 int slack[maxn];
13 
14 bool match(int u)
15 {
16     S[u] = true;
17     for(int v = 1; v <= n; v++) if(!T[v])
18     {
19         int t = Lx[u] + Ly[v] - W[u][v];
20         if(0 == t)
21         {
22             T[v] = true;
23             if(!lft[v] || match(lft[v]))
24             {
25                 lft[v] = u;
26                 return true;
27             }
28         }
29         else slack[v] = min(slack[v], t);
30     }
31     return false;
32 }
33 
34 void update()
35 {
36     int a = 100000000;
37     for(int i = 1; i <= n; i++) if(!T[i]) a = min(a, slack[i]);
38     for(int i = 1; i <= n; i++)
39     {
40         if(S[i]) Lx[i] -= a;
41 
42         if(T[i]) Ly[i] += a;
43         else slack[i] -= a;
44     }
45 }
46 
47 void KM()
48 {
49     memset(lft, 0, sizeof(lft));
50     memset(Lx, 0x80, sizeof(Lx));
51     memset(Ly, 0, sizeof(Ly));
52     for(int i = 1; i <= n; i++)
53         for(int j = 1; j <= n; j++)
54             Lx[i] = max(Lx[i], W[i][j]);
55 
56     for(int i = 1; i <= n; i++)
57     {
58         memset(slack, 0x3f, sizeof(slack));
59         for(;;)
60         {
61             memset(S, false, sizeof(S));
62             memset(T, false, sizeof(T));
63             if(match(i)) break;
64             else update();
65         }
66     }
67 }
68 
69 int main()
70 {
71     int T; scanf("%d", &T);
72 
73     while(T--)
74     {
75         scanf("%d%d", &n, &m);
76         memset(W, 0x80, sizeof(W));
77         for(int i = 0; i < m; i++)
78         {
79             int u, v, d; scanf("%d%d%d", &u, &v, &d);
80             W[u][v] = max(W[u][v], -d);
81         }
82 
83         KM();
84 
85         int ans = 0;
86         for(int i = 1; i <= n; i++) ans += W[lft[i]][i];
87         printf("%d\n", -ans);
88     }
89 
90     return 0;
91 }
代码君

 

posted @ 2015-09-05 10:07  AOQNRMGYXLMV  阅读(134)  评论(0)  编辑  收藏  举报