Sicily 1034. Forest

 1 #include <iostream>
 2 #include <cstring>
 3 #include <queue>
 4 using namespace std;
 5 
 6 bool path[101][101];
 7 bool visited[101];
 8 bool Root[101];
 9 
10 int main()
11 {
12     int n, m;
13     while (cin >> n >> m && n)
14     {
15         memset(path, false, sizeof(path));
16         memset(visited, false, sizeof(visited));
17         memset(Root, true, sizeof(Root));
18 
19         bool flag = n > m ? true : false;
20         for (int i = 1; i <= m; i++)
21         {
22             int node1, node2;
23             cin >> node1 >> node2;
24             if (node1 == node2) flag = false;
25             path[node1][node2] = true;
26         }
27         if (flag == false) {
28             cout << "INVALID\n";
29             continue;
30         }
31         
32         for (int i = 1; i <= n; i++)
33             for (int j = 1; j <= n; j++)
34                 if (path[j][i])
35                     Root[i] = false;
36         int maxwidth = 0;
37         for (int i = 1; i <= n; i++)
38             if (Root[i]) {
39                 maxwidth++;
40                 visited[i] = true;
41             }
42         queue<int> store;
43         int depth, maxdepth;
44         maxdepth = depth = 0;
45         int width[101] = {0};
46         for (int i = 1; i <= n; i++)
47         {
48             if (Root[i])
49             {
50                 store.push(i);
51                 depth = 0;
52                 while (!store.empty())
53                 {
54                     int size = store.size();
55                     width[depth] += size;
56                     while (size--)
57                     {
58                         for (int j = 1; j <= n; j++)
59                             if (path[store.front()][j])
60                             {
61                                 if (!visited[j]) {
62                                     store.push(j);
63                                     visited[j] = true;
64                                 }
65                                 else
66                                     flag = false;
67                             }
68                         store.pop();
69                     }
70                     if (!store.empty())
71                         depth++;
72                 }
73                 maxdepth = depth > maxdepth ? depth : maxdepth;
74             }
75         }
76         
77         for (int i = 1; i <= n; i++)
78             if (!visited[i]) {
79                 flag = false;
80                 break;
81             }
82         
83         for (int i = 0; i <= maxdepth; i++)
84             maxwidth = width[i] > maxwidth ? width[i] : maxwidth;
85         
86         flag == false ? cout << "INVALID" : cout << maxdepth << " " << maxwidth;
87         cout << endl;
88     }
89 
90     return 0;
91 }