图算法（一）——基本图算法（BFS，DFS及其应用）（1）

 1 #include<stack>
 2 #include<vector>
 3 #include<queue>
 4 #include<algorithm>
 5 
 6 using namespace std;
 7 #define INF 99999999
 8 #define NIL -1
 9 int n;
10 int g[1000][1000];
11 struct Node
12 {
13     int color;
14     int d;            //distance
15     int pi;            //pi,ancestor
16 }t[1000];
17 queue<int> q;
18 
19 void BFS(int s)
20 {
21     for (int i=0;i<n;i++)
22     {
23         if (i!=s)
24         {
25             t[i].color = 0;
26             t[i].d = INF;
27             t[i].pi = NIL;
28         }
29     }
30     t[s].color = 1;
31     t[s].d = 0;
32     t[s].pi = NIL;
33     q.push(s);
34     while (!q.empty())
35     {
36         int u = q.front();
37         q.pop();
38         for (int v=0;v<n;v++)
39         {
40             if ((g[u][v] == 1)&&(u != v))
41             {    
42                 if (t[v].color == 0)
43                 {
44                     t[v].color = 1;
45                     t[v].d = t[u].d + 1;
46                     t[v].pi = u;
47                     q.push(v);
48                 }
49             }
50         }
51         t[u].color = 1;
52     }
53 }
54 
55 /*
56 int main()
57 {
58     while (cin>>n)
59     {
60         for (int i=0;i<n;i++)
61         {
62             for (int j=0;j<n;j++)
63             {
64                 cin>>g[i][j];
65             }
66         }
67         int s;
68         cin>>s;
69         BFS(s);
70         for (int i=0;i<n;i++)
71         {
72             cout<<i<<" "<<t[i].d<<" "<<t[i].pi<<endl;
73         }
74     }
75     return 0;
76 }
77 */