Hdu 5285 wyh2000 and pupil (bfs染色判断奇环) (二分图匹配)

 1 #include <queue>
 2 #include <vector>
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <iostream>
 6 #include <algorithm>
 7 using namespace std;
 8 const int maxn = 100010;
 9 vector < int > G[maxn];
10 
11 int x, y, n, m, vis[maxn], flag;
12 void bfs (int s)
13 {
14     int p, q, zreo, one, num;
15     queue <int> Q;
16     zreo = 1;
17     one = vis[s] = 0;
18     Q.push(s);
19     while (!Q.empty())
20     {
21         p = Q.front();
22         Q.pop();
23         num = (vis[p] + 1) % 2;
24         for (int i=0; i<G[p].size(); i++)
25         {
26             q = G[p][i];
27             if (vis[q]!=-1 && num != vis[q])
28                 flag = 1;
29             if (vis[q]==-1)
30             {
31                 Q.push(q);
32                 vis[q] = num;
33                 if (num == 0)
34                     zreo ++;
35                 else
36                     one ++;
37             }
38         }
39     }
40     x += max (zreo, one);
41     y += min (one, zreo);
42 }
43 int main ()
44 {
45     int t;
46     scanf ("%d", &t);
47     while (t --)
48     {
49         scanf ("%d %d", &n, &m);
50         memset (vis, -1, sizeof(vis));
51         for (int i=0; i<=n; i++)
52             G[i].clear();
53         x = y = flag = 0;
54         while (m --)
55         {
56             int a, b;
57             scanf ("%d %d", &a, &b);
58             G[a].push_back (b);
59             G[b].push_back (a);
60         }
61         for (int i=1; i<=n; i++)
62         {
63             if (vis[i] == -1)
64                 bfs (i);
65             if (flag)
66                 break;
67         }
68         if (x == n)
69         {
70             x --;
71             y ++;
72         }
73         if (flag || x < 1 || y < 1)
74             printf ("Poor wyh\n");
75         else
76             printf ("%d %d\n", x, y);
77     }
78     return 0;
79 }