最短路复杂度估计错误 以为SPFA是N*m的 用了dij超时 用SPFA直接跑就好了
O（k*e) K 一般为2,3；
1 /* 2 ID: shangca2 3 LANG: C++ 4 TASK: butter 5 */ 6 #include <iostream> 7 #include<cstdio> 8 #include<cstring> 9 #include<algorithm> 10 #include<stdlib.h> 11 #include<queue> 12 using namespace std; 13 #define M 1500 14 #define P 850 15 #define N 550 16 #define INF 0xfffffff 17 struct node 18 { 19 int u,v,w,next; 20 }ed[M<<1]; 21 int t,head[P],dis[P],a[N],n,p,c,vis[P],f[P],k[P],o[P][P]; 22 void init() 23 { 24 t = 0; 25 memset(head,-1,sizeof(head)); 26 } 27 void add(int u,int v,int w) 28 { 29 ed[t].u = u; 30 ed[t].v = v; 31 ed[t].w = w; 32 ed[t].next = head[u]; 33 head[u] = t++; 34 } 35 void spfa(int st) 36 { 37 int i; 38 memset(vis,0,sizeof(vis)); 39 for(i = 1; i <= p ; i++) 40 dis[i] = INF; 41 dis[st] = 0; 42 queue<int>q; 43 vis[st] = 1; 44 q.push(st); 45 while(!q.empty()) 46 { 47 int u = q.front(); 48 q.pop(); 49 vis[u] = 0; 50 for(i = head[u]; i != -1 ;i = ed[i].next) 51 { 52 int v = ed[i].v; 53 if(ed[i].w+dis[u]<dis[v]) 54 { 55 dis[v] = ed[i].w+dis[u]; 56 if(!vis[v]) 57 { 58 vis[v] = 1; 59 q.push(v); 60 } 61 } 62 } 63 } 64 for(i = 1; i <= p ; i++) 65 { 66 if(o[st][i]>dis[i]) 67 { 68 o[st][i] = dis[i]; 69 o[i][st] = dis[i]; 70 } 71 } 72 } 73 int main() 74 { 75 freopen("butter.in","r",stdin); 76 freopen("butter.out","w",stdout); 77 int i,j,u,v,w; 78 init(); 79 cin>>n>>p>>c; 80 for(i =0 ;i <= p ; i++) 81 for(j = 1; j <= p ; j++) 82 o[i][j] = INF; 83 for(i = 1; i <= n ;i++) 84 cin>>a[i]; 85 for(i = 1; i <= c ;i++) 86 { 87 scanf("%d%d%d",&u,&v,&w); 88 add(u,v,w); 89 add(v,u,w); 90 } 91 for(i = 1; i <= n ;i++) 92 { 93 if(!f[a[i]]) 94 { 95 f[a[i]] = 1; 96 spfa(a[i]); 97 } 98 } 99 int minz = INF; 100 for(i = 1; i <= p ; i++) 101 { 102 int s = 0; 103 for(j = 1 ; j <= n ; j++) 104 { 105 if(a[j]!=i) 106 s+=o[a[j]][i]; 107 } 108 minz = min(minz,s); 109 } 110 printf("%d ",minz); 111 return 0; 112 }