題目地址:1034. Forest
思路:
待續.......
具體代碼如下:
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 }