SDUT 最短路径（二维SPFA）

http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2622

 1 #include<stdio.h>

 2 #include<string.h>

 3 #include<queue>

 4 #include<vector>

 5 using namespace std;

 6 const long long INF = 1LL << 40;

 7 struct node

 8 {

 9     int v,w;

10 };

11 vector<struct node>map[110];

12 int inque[110];

13 long long dis[110][12];

14 int s,t,x,n,m;

15 

16 void spfa()

17 {

18     queue<int>que;

19     for(int i = 0; i < n; i++)

20         for(int k = 0; k <= x; k++)

21             dis[i][k] = INF;

22     dis[s][0] = 0;

23     memset(inque,0,sizeof(inque));

24 

25     que.push(s);

26     inque[s] = 1;

27 

28     while(!que.empty())

29     {

30         int u = que.front();

31         inque[u] = 0;

32         que.pop();

33         for(int i = 0; i < map[u].size(); i++)

34         {

35             int v = map[u][i].v;

36             for(int k = 0; k < x; k++)

37             {

38                 if(dis[u][k] < INF && dis[v][(k+1)%x] > dis[u][k]+map[u][i].w)

39                 {

40                     dis[v][(k+1)%x] = dis[u][k]+map[u][i].w;

41                     if(!inque[v])

42                     {

43                         que.push(v);

44                         inque[v] = 1;

45                     }

46                 }

47             }

48         }

49     }

50 }

51 int main()

52 {

53     int test;

54     scanf("%d",&test);

55     while(test--)

56     {

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

58         for(int i = 0; i < n; i++)

59             map[i].clear();

60         int u,v,w;

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

62         {

63             scanf("%d %d %d",&u,&v,&w);

64             map[u].push_back((struct node){v,w});

65         }

66         scanf("%d %d %d",&s,&t,&x);

67         spfa();

68         if(dis[t][0] >= INF)

69             printf("No Answer!\n");

70         else printf("%lld\n",dis[t][0]);

71     }

72     return 0;

73 }

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