POJ - 2387 Til the Cows Come Home （最短路Dijkstra+优先队列）

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<queue>
 4 #include<string.h>
 5 using namespace std ;
 6 
 7 const int INF = 0x3f3f3f3f;
 8 int G[2000][2000];
 9 int d[2000];
10 
11 int i ,j;
12 
13 struct node{
14     int num;
15     int dis;
16     friend bool operator<(node a ,node b)
17     {
18         return a.dis>b.dis;
19     }
20 };
21 
22 int main()
23 {
24     int M , N;
25     int x,y,D;
26     
27     priority_queue<node>que;
28     
29     
30     while(scanf("%d%d",&M,&N)!=EOF)
31     {
32         for( i = 1 ;i <= N ;i++)
33         {
34             for( j = 1 ;j <= N ;j++)
35             {
36                 G[i][j] = INF;
37             }
38         }
39         
40             for(int i  = 1 ; i <= N ;i++)
41         {
42             G[i][i] = 0;
43         }
44         for( i = 1; i <= M ;i++)
45         {
46             scanf("%d%d%d",&x,&y,&D);
47             
48                 if(G[x][y]>D)
49                 {
50                     G[x][y] = D;
51                     G[y][x] = D;
52                 }
53             
54         }
55         memset(d,0x3f,sizeof(d));
56         d[1] = 0;
57         que.push({1,0});
58         while(!que.empty())
59         {
60             node tp = que.top();
61 
62             que.pop();
63             
64             for(i = 1 ;i <= N ;i++)
65             {
66                 if(G[tp.num][i])
67                 {
68                     if(d[i]>d[tp.num]+G[tp.num][i])
69                     {
70                         d[i] = d[tp.num] + G[tp.num][i];
71                         que.push({i,d[i]});
72                     }
73                 }
74             }
75         }
76         
77         printf("%d\n",d[N]);
78         while(!que.empty())
79         {
80             que.pop();
81         }
82         
83         
84     }
85     return 0;
86 }