题目：http://acm.hdu.edu.cn/showproblem.php?pid=1874
spfa 模板
1 #include<iostream> 2 #include<stdio.h> 3 #include<string.h> 4 #include<queue> 5 using namespace std; 6 7 const int INF=1<<28; 8 int cnt,head[1100],d[210],vis[210],n,m; 9 queue<int>q; 10 11 struct node 12 { 13 int u,v,w,next; 14 } edge[1100]; 15 16 void add(int u,int v,int w) 17 { 18 edge[cnt].u=u; 19 edge[cnt].v=v; 20 edge[cnt].w=w; 21 edge[cnt].next=head[u]; 22 head[u]=cnt++; 23 }; 24 25 void spfa(int s) 26 { 27 int i,u,v; 28 for(i=0; i<n; i++) 29 d[i]=INF; 30 d[s]=0; 31 32 q.push(s); 33 vis[s]=1; 34 while(!q.empty()) 35 { 36 u=q.front(); 37 q.pop(); 38 vis[u]=0; 39 for(i=head[u]; i!=-1; i=edge[i].next) 40 { 41 v=edge[i].v; 42 if(d[u]+edge[i].w<d[v]) 43 { 44 d[v]=d[u]+edge[i].w; 45 if(!vis[v]) 46 { 47 vis[v]=1; 48 q.push(v); 49 } 50 } 51 } 52 } 53 }; 54 int main() 55 { 56 int u,v,w,s,t; 57 while(cin>>n>>m) 58 { 59 cnt=0; 60 memset(head,-1,sizeof(head)); 61 memset(vis,0,sizeof(vis)); 62 while(m--) 63 { 64 cin>>u>>v>>w; 65 add(u,v,w); 66 add(v,u,w); 67 } 68 cin>>s>>t; 69 spfa(s); 70 if(d[t]<INF) cout<<d[t]<<endl; 71 else cout<<-1<<endl; 72 } 73 }
floyd 模板
1 #include <stdio.h> 2 #include <string.h> 3 const int oo = 1<<28; 4 int map[201][201]; 5 6 int n, m; 7 void floyd() 8 { 9 int k,i,j; 10 for( k = 0; k < n; k++) 11 for( i = 0; i < n; i++) 12 for( j = 0; j < n; j++) 13 if(map[i][k]+map[k][j] < map[i][j]) 14 map[i][j] = map[i][k]+map[k][j]; 15 } 16 void init() 17 { 18 int i,j; 19 for( i = 0; i < n; i++) 20 { 21 for(j = 0; j < n; j++) 22 map[i][j] = oo; 23 map[i][i] = 0; 24 } 25 } 26 int main() 27 { 28 int i; 29 while(~scanf("%d %d", &n, &m)) 30 { 31 init(); 32 int u, v, w; 33 for( i = 0; i < m; i++) 34 { 35 scanf("%d %d %d", &u, &v, &w); 36 if(map[u][v] > w) 37 { 38 map[u][v] = w; 39 map[v][u] = w; 40 } 41 } 42 floyd(); 43 scanf("%d %d", &u, &v); 44 if(map[u][v] < oo) 45 printf("%d ", map[u][v]); 46 else 47 printf("-1 "); 48 } 49 return 0; 50 }