USACO 2.4 Bessie Come Home(最短路）

水题，没注意无向边，2Y。

 1 /*

 2   ID: cuizhe

 3   LANG: C++

 4   TASK: comehome

 5 */

 6 #include <iostream>

 7 #include <cstdio>

 8 #include <cstring>

 9 #include <cmath>

10 #include <algorithm>

11 using namespace std;

12 #define N 100000000

13 int p[101][101];

14 int judge(char ch)

15 {

16     if(ch >= 'A'&&ch <= 'Z')

17     return ch-'A'+1;

18     else

19     return ch-'a'+27;

20 }

21 int main()

22 {

23     int i,j,k,n,sv,ev,w,ans,t;

24     freopen("comehome.in","r",stdin);

25     freopen("comehome.out","w",stdout);

26     char n1[2],n2[2];

27     scanf("%d",&n);

28     for(i = 1;i <= 52;i ++)

29     {

30         for(j = 1;j <= 52;j ++)

31         p[i][j] = N;

32         p[i][i] = 0;

33     }

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

35     {

36         scanf("%s%s%d",n1,n2,&w);

37         sv = judge(n1[0]);

38         ev = judge(n2[0]);

39         if(p[sv][ev] > w)

40         {

41             p[sv][ev] = w;

42             p[ev][sv] = w;

43         }

44     }

45     for(i = 1;i <= 52;i ++)

46     {

47         for(j = 1;j <= 52;j ++)

48         {

49             for(k = 1;k <= 52;k ++)

50             {

51                 if(p[j][k] > p[j][i]+p[i][k])

52                 p[j][k] = p[j][i]+p[i][k];

53             }

54         }

55     }

56     ans = N;

57     for(i = 1;i <= 25;i ++)

58     {

59         if(ans > p[i][26])

60         {

61             ans = p[i][26];

62             t = i;

63         }

64     }

65     printf("%c %d\n",t+'A'-1,ans);

66     return 0;

67 }