hdu 2544 hdu 1874 Dijkstra 模板题

 1 # include <iostream>
 2 # include <cstdio>
 3 # include <cstring>
 4 # include <algorithm>
 5 # include <cmath>
 6 # define LL long long
 7 using namespace std ;
 8 
 9 const int MAXN=200;
10 const int INF=0x3f3f3f3f;
11 int n ;
12 bool vis[MAXN];
13 int cost[MAXN][MAXN] ;
14 int lowcost[MAXN] ;
15 int pre[MAXN];
16 void Dijkstra(int beg)
17 {
18     for(int i=0;i<n;i++)
19     {
20         lowcost[i]=INF;vis[i]=false;pre[i]=-1;
21     }
22     lowcost[beg]=0;
23     for(int j=0;j<n;j++)
24     {
25         int k=-1;
26         int Min=INF;
27         for(int i=0;i<n;i++)
28             if(!vis[i]&&lowcost[i]<Min)
29             {
30                 Min=lowcost[i];
31                 k=i;
32             }
33             if(k==-1)break;
34             vis[k]=true;
35             for(int i=0;i<n;i++)
36                 if(!vis[i]&&lowcost[k]+cost[k][i]<lowcost[i])
37                 {
38                     lowcost[i]=lowcost[k]+cost[k][i];
39                         pre[i]=k;
40                 }
41     }
42 }
43 
44 int main ()
45 {
46   //  freopen("in.txt","r",stdin) ;
47     int m ;
48     while (scanf("%d %d" , &n , &m) !=EOF)
49     {
50         if (n==0 && m==0)
51             break ;
52         int u , v , w ;
53         int i , j ;
54         for (i = 0 ; i < n ; i++)
55             for (j = 0 ; j < n ; j++)
56                cost[i][j] = INF ;
57          while(m--)
58         {
59             scanf("%d%d%d" , &u , &v , &w) ;
60             if (w < cost[u][v]) //防止重边
61             {
62                 cost[u][v] = w ;
63                 cost[v][u] = w ;
64             }
65         }
66         Dijkstra(0) ;
67         printf("%d\n" , lowcost[n-1]) ;
68     }
69 
70     return 0 ;
71 }

 1 # include <iostream>
 2 # include <cstdio>
 3 # include <cstring>
 4 # include <algorithm>
 5 # include <cmath>
 6 # define LL long long
 7 using namespace std ;
 8 
 9 const int MAXN=300;
10 const int INF=0x3f3f3f3f;
11 int n ;
12 bool vis[MAXN];
13 int cost[MAXN][MAXN] ;
14 int lowcost[MAXN] ;
15 int pre[MAXN];
16 void Dijkstra(int beg)
17 {
18     for(int i=0;i<n;i++)
19     {
20         lowcost[i]=INF;vis[i]=false;pre[i]=-1;
21     }
22     lowcost[beg]=0;
23     for(int j=0;j<n;j++)
24     {
25         int k=-1;
26         int Min=INF;
27         for(int i=0;i<n;i++)
28             if(!vis[i]&&lowcost[i]<Min)
29             {
30                 Min=lowcost[i];
31                 k=i;
32             }
33             if(k==-1)
34                 break ;
35             vis[k]=true;
36             for(int i=0;i<n;i++)
37                 if(!vis[i]&&lowcost[k]+cost[k][i]<lowcost[i])
38                 {
39                     lowcost[i]=lowcost[k]+cost[k][i];
40                         pre[i]=k;
41                 }
42     }
43 
44 }
45 
46 int main ()
47 {
48   //  freopen("in.txt","r",stdin) ;
49     int m ;
50     while (scanf("%d %d" , &n , &m) !=EOF)
51     {
52 
53         int u , v , w ;
54         int i , j ;
55         for (i = 0 ; i < n ; i++)
56             for (j = 0 ; j < n ; j++)
57                cost[i][j] = INF ;
58         while(m--)
59         {
60             scanf("%d%d%d" , &u , &v , &w) ;
61             if (w < cost[u][v]) //防止重边
62             {
63                 cost[u][v] = w ;
64                 cost[v][u] = w ;
65             }
66         }
67         scanf("%d %d" , &u , &v) ;
68         Dijkstra(u) ;
69         if (lowcost[v] != INF)
70            printf("%d\n" , lowcost[v]) ;
71         else
72            printf("-1\n") ;
73     }
74 
75     return 0 ;
76 }