hdu 1596 find the safest road

http://acm.hdu.edu.cn/showproblem.php?pid=1596

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <algorithm>

 4 #define maxn 1001

 5 using namespace std;

 6 

 7 double g[maxn][maxn];

 8 int dis[maxn];

 9 bool vis[maxn];

10 int n,a,b;

11 

12 void floyd()

13 {

14     for(int k=1; k<=n; k++)

15     {

16         for(int i=1; i<=n; i++)

17         {

18             if(g[i][k]==0) continue;

19             for(int j=1; j<=n; j++)

20             {

21                 if(g[i][j]<g[i][k]*g[k][j])

22                 {

23                     g[i][j]=g[i][k]*g[k][j];

24                 }

25             }

26         }

27     }

28 }

29 

30 int main()

31 {

32     while(scanf("%d",&n)!=EOF)

33     {

34         for(int i=1; i<=n; i++)

35         {

36             for(int j=1; j<=n; j++)

37             {

38                 scanf("%lf",&g[i][j]);

39             }

40         }

41         floyd();

42         int m;

43         scanf("%d",&m);

44         for(int i=1; i<=m; i++)

45         {

46             scanf("%d%d",&a,&b);

47             if(g[a][b]!=0)

48                 printf("%.3lf\n",g[a][b]);

49             else

50                 printf("What a pity!\n");

51         }

52     }

53     return 0;

54 }

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