poj 1125

floyd 求每对顶点间最短路径

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1. #include <iostream>
   
2. #include <cstring>
   
3. 
   
4. #define inf 2000000000
   
5. 
   
6. using namespace std;
   
7. #define MAX_V (100+1)
   
8. 
   
9. int E[MAX_V][MAX_V];
   
10. int D[MAX_V][MAX_V];
    
11. int n;
    
12. 
    
13. 
    
14. int floyd()
    
15. {
    
16. 
    
17. 
    
18.     for(int k = 1;k<=n ;k++)
    
19.     {
    
20.         for(int i=1;i<=n;i++)
    
21.         {
    
22.             for(int j=1;j<=n;j++)
    
23.             {
    
24.                 int kw=D[i][k] + D[k][j];
    
25.                 if( kw > 0 && kw < D[i][j])
    
26.                     D[i][j] = kw;
    
27.             }
    
28.         }
    
29.     }
    
30. 
    
31.     int minw=inf;
    
32.     int mink=-1;
    
33. 
    
34.     for(int k=1;k<=n;k++)
    
35.     {
    
36.         int maxw = 0;
    
37.         for(int i=1;i<=n;i++)
    
38.         {
    
39.             if(k != i && D[k][i] > maxw)
    
40.             {
    
41.                 maxw=D[k][i];
    
42.             }
    
43.         }
    
44. 
    
45.         if(maxw < minw)
    
46.         {
    
47.             minw = maxw;
    
48.             mink = k;
    
49.         }
    
50. 
    
51.     }
    
52. 
    
53.     cout<<mink<<" "<<minw<<endl;
    
54.     return 0;
    
55. }
    
56. 
    
57. int main()
    
58. {
    
59.     while(cin >> n)
    
60.     {
    
61.         if (n == 0)
    
62.             break;
    
63. 
    
64.         //memset(V,0,sizoef(V));
    
65.         //memset(E,0,sizeof(E));
    
66.         for(int i=1;i<=n;i++)
    
67.         {
    
68.             for(int j=1;j<=n;j++)
    
69.             {
    
70.                 if(i == j)
    
71.                     E[i][j] = 0;
    
72.                 else
    
73.                     E[i][j] = inf;
    
74. 
    
75.                 D[i][j]=inf;
    
76.             }
    
77.         }
    
78. 
    
79. 
    
80.         int m,v,w;
    
81.         for(int i=1;i<=n;i++)
    
82.         {
    
83.             cin>>m;
    
84.             for(int j=1;j<=m;j++)
    
85.             {
    
86.                 cin>>v>>w;
    
87.                 //i->v w
    
88.                 E[i][v]=w;
    
89.                 D[i][v]=w;
    
90.             }
    
91.         }
    
92. 
    
93.         
    
94.         floyd();
    
95.     }
    
96. }