hdu 2066 最短路

建立一个超级源点0和超级汇点n，求0到n的最短路就行了。

dijstra：

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <cstdio>
 5 using namespace std;
 6 
 7 const int INF = 9999999;
 8 const int N = 2001;
 9 const int M = 100000;
10 int head[N];
11 int dist[N];
12 bool visit[N];
13 int n, e;
14 
15 struct Edge
16 {
17     int v, next, w;
18 } edge[M];
19 
20 void addEdge( int u, int v, int w )
21 {
22     edge[e].v = v;
23     edge[e].w = w;
24     edge[e].next = head[u];
25     head[u] = e++;
26 }
27 
28 void dij( int s )
29 {
30     memset( visit, false, sizeof(visit) );
31     for ( int i = 0; i <= n; i++ )
32     {
33         dist[i] = INF;
34     }
35     dist[s] = 0;
36     for ( int i = 0; i <= n; i++ )
37     {
38         int minn = INF, u;
39         for ( int j = 0; j <= n; j++ )
40         {
41             if ( !visit[j] && dist[j] < minn )
42             {
43                 minn = dist[j];
44                 u = j;
45             }
46         }
47         visit[u] = true;
48         for ( int j = head[u]; j != -1; j = edge[j].next )
49         {
50             int v = edge[j].v, w = edge[j].w;
51             if ( !visit[v] && dist[u] + w < dist[v] )
52             {
53                 dist[v] = dist[u] + w;
54             }
55         }
56     }
57 }
58 
59 int main ()
60 {
61     int t, s, d;
62     while ( scanf("%d%d%d", &t, &s, &d) != EOF )
63     {
64         e = n = 0;
65         memset( head, -1, sizeof(head) );
66         while ( t-- )
67         {
68             int u, v, w;
69             scanf("%d%d%d", &u, &v, &w);
70             addEdge( u, v, w );
71             addEdge( v, u, w );
72             if ( u > n ) n = u;
73             if ( v > n ) n = v;
74         }
75         n++;
76         for ( int i = 0; i < s; i++ )
77         {
78             int tmp;
79             scanf("%d", &tmp);
80             addEdge( 0, tmp, 0 );
81         }
82         for ( int i = 0; i < d; i++ )
83         {
84             int tmp;
85             scanf("%d", &tmp);
86             addEdge( tmp, n, 0 );
87         }
88         dij(0);
89         printf("%d\n", dist[n]);
90     }
91     return 0;
92 } 

spfa：

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <cstdio>
 5 using namespace std;
 6 
 7 const int INF = 9999999;
 8 const int N = 2001;
 9 const int M = 100000;
10 int head[N];
11 int dist[N];
12 bool visit[N];
13 int n, e;
14 
15 struct Edge
16 {
17     int v, next, w;
18 } edge[M];
19 
20 void addEdge( int u, int v, int w )
21 {
22     edge[e].v = v;
23     edge[e].w = w;
24     edge[e].next = head[u];
25     head[u] = e++;
26 }
27 
28 void spfa( int s )
29 {
30     for ( int i = 0; i <= n; i++ )
31     {
32         dist[i] = INF;
33         visit[i] = false;
34     }
35     dist[s] = 0;
36     visit[s] = true;
37     int q[N], top = 0;
38     q[top] = s;
39     top = ( top + 1 ) % ( n + 1 );
40     for ( int i = 0; i != top; i = ( i + 1 ) % ( n + 1 ) )
41     {
42         int u = q[i];
43         visit[u] = false;
44         for ( int j = head[u]; j != -1; j = edge[j].next )
45         {
46             int v = edge[j].v, w = edge[j].w;
47             if ( dist[v] > dist[u] + w )
48             {
49                 dist[v] = dist[u] + w;
50                 if ( !visit[v] )
51                 {
52                     q[top] = v;
53                     top = ( top + 1 ) % ( n + 1 );
54                     visit[v] = true;
55                 }
56             }
57         }
58     }
59 }
60 
61 int main ()
62 {
63     int t, s, d;
64     while ( scanf("%d%d%d", &t, &s, &d) != EOF )
65     {
66         e = n = 0;
67         memset( head, -1, sizeof(head) );
68         while ( t-- )
69         {
70             int u, v, w;
71             scanf("%d%d%d", &u, &v, &w);
72             addEdge( u, v, w );
73             addEdge( v, u, w );
74             if ( u > n ) n = u;
75             if ( v > n ) n = v;
76         }
77         n++;
78         for ( int i = 0; i < s; i++ )
79         {
80             int tmp;
81             scanf("%d", &tmp);
82             addEdge( 0, tmp, 0 );
83         }
84         for ( int i = 0; i < d; i++ )
85         {
86             int tmp;
87             scanf("%d", &tmp);
88             addEdge( tmp, n, 0 );
89         }
90         spfa(0);
91         printf("%d\n", dist[n]);
92     }
93     return 0;
94 }

 

posted @ 2015-07-23 09:23  hxy_has_been_used  阅读(149)  评论(0)  编辑  收藏  举报