hdu 1874 畅通工程续 (dijkstra(不能用于负环))

 1 #include <cmath>
 2 #include <cstdio>
 3 #include <climits>
 4 #include <algorithm>
 5 #define INF 0xffffff
 6 using namespace std;
 7 
 8 int n, m, my_map[210][210], my_start, my_end;
 9 
10 int my_dijkstra()
11 {
12     int my_dis[210], my_book[210] = {0};
13     my_book[my_start] = 1;
14     for (int i = 0; i < n; ++ i)
15         my_dis[i] = my_map[i][my_start];
16 
17     while (1)
18     {
19         int my_min = INF, my_temp_pos = -1;
20         for (int i = 0; i < n; ++ i)
21         {
22             if (!my_book[i] && my_dis[i] < my_min)
23             {
24                 my_min = my_dis[i];
25                 my_temp_pos = i;
26             }
27         }
28         if (my_temp_pos == -1) break;
29         my_book[my_temp_pos] = 1;
30 
31         for (int i = 0; i < n; ++ i)
32         {
33             if (!my_book[i] && my_dis[i] > my_map[i][my_temp_pos] + my_dis[my_temp_pos])
34                 my_dis[i] = my_map[i][my_temp_pos] + my_dis[my_temp_pos];
35         }
36     }
37     if (my_dis[my_end] == INF) return -1;
38     return my_dis[my_end];
39 }
40 
41 int main()
42 {
43     /**
44         Date Input Initialize
45     */
46     while (~scanf("%d%d", &n, &m))
47     {
48         for (int i = 0; i < n; ++ i)
49             for (int j = 0; j < n; ++ j)
50                 my_map[i][j] = i == j ? 0 : INF;
51 
52         for (int i = 0; i < m; ++ i)
53         {
54             int a, b, a_b_dis;
55             scanf("%d%d%d", &a, &b, &a_b_dis);
56             if (my_map[a][b] > a_b_dis)
57                 my_map[a][b] = my_map[b][a] = a_b_dis;
58         }
59         scanf("%d%d", &my_start, &my_end);
60         printf("%d\n", my_dijkstra());
61     }
62     return 0;
63 }