HDOJ 2544 - 最短路 SPFA算法

因为QM混乱的原因，白白WA了好几次

 

AC     0MS    228K

 1 #include <queue>

 2 #include <stdio.h>

 3 #include <stdlib.h>

 4 #include <memory.h>

 5 using namespace std;

 6 

 7 const int maxn = 101;

 8 const int INF = 0x3F3F3F3F;

 9 

10 int a, b, c, nNum, mNum;

11 int g[maxn][maxn], QM[maxn], dist[maxn];

12 

13 int SPFA()

14 {

15     int x;

16     queue <int> q;

17     

18     q.push(1);

19     QM[1] = 1, dist[1] = 0;

20     

21     while (!q.empty())

22     {

23         x = q.front();

24         q.pop();

25         QM[x] = 0; /* Took Away*/

26         

27         for (int i=1; i<=nNum; ++i)

28         {

29             if (dist[i] > dist[x]+g[x][i])

30             {

31                 dist[i] = dist[x] + g[x][i]; /* change the weight */

32                 

33                 /* push into queue if vertex i is QM of queue */

34                 if (QM[i] == 0)

35                 {

36                     QM[i] = 1;

37                     q.push(i);

38                 }

39             }    

40         }/* End of For */

41     }/* End of While */

42     

43     return dist[nNum];

44 }/* SPFA */

45 

46 int main()

47 {

48     while (~scanf("%d %d", &nNum, &mNum), nNum+mNum!=0)

49     {

50         memset(g, INF, sizeof(g));

51         memset(QM, 0, sizeof(QM));

52         memset(dist, INF, sizeof(dist));

53         

54         for (int i=1; i<=mNum; ++i)

55         {

56             scanf("%d %d %d", &a, &b, &c);

57             g[a][b] = g[b][a] = c; /* Adjcent Matrix */

58         }/* End of For */

59         

60         printf("%d\n", SPFA());    /* Solve with spfa algorithm */

61     }/* End of While */

62     

63     return 0;

64 }