想偷点懒用矩阵存 一直WA 后来看讨论说有重边改为邻接表 这题边可能走了不止一次 我设的最多两次可过
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 using namespace std; 7 #define INF 0xfffffff 8 struct node 9 { 10 int u,v,w1,w2,d,next; 11 }ed[22]; 12 int head[12]; 13 int n,m,p[12][12],ans; 14 int vis[12],t; 15 void init() 16 { 17 t = 0; 18 memset(head,-1,sizeof(head)); 19 } 20 void add(int u,int v,int w1,int w2,int d) 21 { 22 ed[t].u = u; 23 ed[t].v = v; 24 ed[t].w1 = w1; 25 ed[t].w2 = w2; 26 ed[t].d = d; 27 ed[t].next = head[u]; 28 head[u] = t++; 29 } 30 void dfs(int u,int sum) 31 { 32 int i,s=sum; 33 if(sum>ans) 34 return ; 35 if(u==n) 36 { 37 ans = sum; 38 return ; 39 } 40 for(i = head[u] ; i!= -1; i = ed[i].next) 41 { 42 int v = ed[i].v; 43 int tt = vis[v]; 44 if(p[u][v]<3) 45 { 46 vis[v] = 1; 47 p[u][v]++; 48 if(ed[i].d==u||ed[i].d==i||vis[ed[i].d]) 49 { 50 sum+=min(ed[i].w1,ed[i].w2); 51 } 52 else 53 { 54 sum+=ed[i].w2; 55 } 56 dfs(v,sum); 57 sum = s; 58 p[u][v]--; 59 vis[v] = tt; 60 } 61 } 62 } 63 int main() 64 { 65 int a,b,c,pp,r; 66 while(scanf("%d%d",&n,&m)!=EOF) 67 { 68 init(); 69 memset(vis,0,sizeof(vis)); 70 memset(p,0,sizeof(p)); 71 ans = INF; 72 while(m--) 73 { 74 scanf("%d%d%d%d%d",&a,&b,&c,&pp,&r); 75 add(a,b,pp,r,c); 76 } 77 vis[1] = 1; 78 dfs(1,0); 79 if(ans!=INF) 80 printf("%d ",ans); 81 else 82 puts("impossible"); 83 } 84 return 0; 85 }