hdu3339In Action（最短路+01背包）

http://acm.hdu.edu.cn/showproblem.php?pid=3339

最短路+01背包

以耗油量为V 以pow为价值

View Code

 1 #include <iostream>

 2 #include<cstdio>

 3 #include<string.h>

 4 using namespace std;

 5 #define INF 0x3f3f3f

 6 int w[101][101],p[101],pi[101],f[10001];

 7 int main()

 8 {

 9     int i,j,k,n,m,t,a,b,c,v;

10     scanf("%d",&t);

11     while(t--)

12     {

13         memset(f,0,sizeof(f));

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

15         for(i =0  ; i <= n ; i++)

16         for(j = 0 ; j <= n ; j++)

17         w[i][j] = INF;

18         for(i = 1; i <= m ;i++)

19         {

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

21             if(w[a][b]>c)

22             {

23                 w[a][b] = c;

24                 w[b][a] = c;

25             }

26         }

27         int s = 0,v =0 ;

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

29         {

30             scanf("%d",&pi[i]);

31             s+=pi[i];

32         }

33         for(i = 0; i <= n ; i++)

34         {

35             w[i][i] = 0;

36         }

37         for(i = 0; i <= n ; i++)

38         for(j = 0 ; j <= n; j++)

39         for(k = 0 ; k <= n ; k++)

40         if(w[j][k]>w[j][i]+w[i][k])

41         {

42             w[j][k] = w[j][i]+w[i][k];

43         }

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

45         {

46             p[i] = w[0][i];

47             if(p[i]!=INF)

48             v+=p[i];

49         }

50         int flag = 0,x;

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

52         for(j = v ; j>=p[i] ; j--)

53         {

54             if(f[j]<pi[i]+f[j-p[i]])

55             f[j] = pi[i]+f[j-p[i]];

56         }

57         for(j = 0 ; j <= v ; j++)

58         {

59             if(f[j]>s/2)

60             {

61                 x = j;

62                 flag = 1;

63                 break;

64             }

65         }

66         if(flag)

67         printf("%d\n",x);

68         else

69         printf("impossible\n");

70     }

71     return 0;

72 }