uva 10801【Lift Hopping】

表示对这类题目没feel，抽象。。。参考别人的代码后写出来的，顺便练习了一下FIFO队列实现Bellman-ford算法。。。

代码如下：

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <queue>
 4 #include <cmath>
 5 using namespace std;
 6 
 7 int g[6][105];
 8 int n,k;
 9 int t[6];
10 int d[105];
11 int v[105];
12 
13 void init()
14 {
15     for(int i = 1;i <= n;i ++)
16     {
17         scanf("%d",&t[i]);
18     }
19 
20     memset(g,0,sizeof(g));
21     char ch;
22     int a;
23     for(int i = 1;i <= n;i ++)
24     {
25         scanf("%d",&a);
26         g[i][a] = 1;
27         int b;
28         while((ch = getchar()) != '\n')
29         {
30             scanf("%d",&b);
31             g[i][b] = 1;
32         }
33     }
34 }
35 
36 void solve()
37 {
38     memset(v,0,sizeof(v));
39     memset(d,-1,sizeof(d));
40     d[0] = 0;
41     queue<int> q;
42     q.push(0);
43     v[0] = 1;
44     while(!q.empty())
45     {
46         int x = q.front();
47         q.pop();
48         v[x] = 0;
49         for(int i = 1;i <= n;i ++)
50         {
51             if(g[i][x])
52             {
53                 for(int j = 1;j <= 100;j ++)
54                 {
55                     if(g[i][j])
56                     {
57                         int temp = d[x] + t[i] * abs(j - x) + 60;
58                          if(d[j] == -1 || temp < d[j])
59                         {
60                             d[j] = temp;
61                             if(!v[j])
62                             {
63                                 v[j] = true;
64                                 q.push(j);
65                             }
66                         }
67                     }
68                 }
69             }
70         }
71     }
72 
73     if(d[k] == -1)
74     {
75         printf("IMPOSSIBLE\n");
76     }
77     else if(k == 0)
78     {
79         printf("0\n");
80     }
81     else
82     {
83         printf("%d\n",d[k]-60);
84     }
85 }
86 
87 int main()
88 {
89     while(scanf("%d%d",&n,&k) == 2)
90     {
91         init();
92         solve();
93     }
94 
95     return 0;
96 }

posted on 2012-04-17 21:09 Shirlies 阅读(265) 评论(0) 编辑收藏举报