HDU4360(spfa)

http://acm.hdu.edu.cn/showproblem.php?pid=4360

 1 #include <iostream>

 2 #include <vector>

 3 #include <queue>

 4 #include <cstdio>

 5 using namespace std;

 6 const long long inf = 1ll<<57;

 7 const int Ni = 1320*2;

 8 struct node{

 9     int v,w,e;

10     node(){}

11     node(int a,int b,int c) {v=a;w=b;e=c;}

12 };

13 struct qnode{

14     int v,e;

15     qnode(){}

16     qnode(int a,int b) {v=a;e=b;}

17 };

18 vector<node> eg[Ni];

19 long long d[Ni][4];

20 int num[Ni][4];

21 bool vis[Ni][4];

22 int n,m;

23 void spfa(int s)

24 {

25     int i,j;

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

27         for(j=0;j<=3;j++)

28             d[i][j]=inf,num[i][j]=0,vis[i][j]=0;

29     queue<qnode> q;

30     int el=3,er;

31     d[s][el]=0;

32     vis[s][el]=1;

33     q.push(qnode(s,el));

34     while(!q.empty())

35     {

36         qnode qn=q.front(); q.pop();

37         int u=qn.v;

38         el=qn.e;vis[u][el]=0;

39         for(i=0;i<eg[u].size();i++)

40         {

41             node nd=eg[u][i];

42             int v=nd.v,w=nd.w;

43             er=nd.e;

44             if((el+1)%4==er&&(d[u][el]+w<d[v][er]||d[v][er]==0))

45             {

46                 d[v][er]=d[u][el]+w;

47                 num[v][er]=num[u][el];

48                 if(er==3) num[v][er]++;

49                 if(!vis[v][er])

50                 {

51                     q.push(qnode(v,er));

52                     vis[v][er]=1;

53                 }

54             }

55             else if((el+1)%4==er&&(d[u][el]+w==d[v][er]||d[v][er]==0)&&num[u][el]>=num[v][er])

56             {

57                 num[v][er]=num[u][el];

58                 if(er==3) num[v][er]++;

59 

60                 if(!vis[v][er])

61                 {

62                     q.push(qnode(v,er));

63                     vis[v][er]=1;

64                 }

65             }

66         }

67     }

68 }

69 int main()

70 {

71     int t,cs=1;

72     char str[5];

73     int u,v,w;

74     node nd;

75     cin>>t;

76     while(t--)

77     {

78         scanf("%d%d",&n,&m);

79         for(int i=1;i<=n;i++) eg[i].clear();

80         while(m--)

81         {

82             scanf("%d%d%d%s",&u,&v,&w,str);

83             int e;if(str[0]=='L') e=0;

84             else if(str[0]=='O') e=1;

85             else if(str[0]=='V') e=2;

86             else e=3;

87             eg[u].push_back(node(v,w,e));

88             eg[v].push_back(node(u,w,e));

89         }

90         spfa(1);

91         if(d[n][3]!=inf&&d[n][3]!=0)

92         printf("Case %d: Cute Sangsang, Binbin will come with a donkey after travelling %I64d meters and finding %d LOVE strings at last.\n",cs++,d[n][3],num[n][3]);

93         else

94         printf("Case %d: Binbin you disappoint Sangsang again, damn it!\n",cs++);

95     }

96     return 0;

97 }

测试数据：

3
5 5
1 2 1 L
2 3 1 O
3 4 1 V
4 5 2 E
4 5 1 E
1 4
1 1 1 L
1 1 1 O
1 1 1 V
1 1 1 E
9 12
1 3 2 L
3 5 2 O
5 7 2 V
7 9 2 E
1 2 1 L
2 3 1 O
3 4 1 V
4 5 1 E
5 6 1 L
6 7 1 O
7 8 1 V
8 9 1 E
ans:
4 1
4 1
8 2