poj3411Paid Roads(dfs)

链接

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

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 using namespace std;
 #define INF 0xfffffff
 struct node
 {
     int u,v,w1,w2,d,next;
 }ed[];
 int head[];
 int n,m,p[][],ans;
 int vis[],t;
 void init()
 {
     t = ;
     memset(head,-,sizeof(head));
 }
 void add(int u,int v,int w1,int w2,int d)
 {
     ed[t].u = u;
     ed[t].v = v;
     ed[t].w1 = w1;
     ed[t].w2 = w2;
     ed[t].d = d;
     ed[t].next = head[u];
     head[u] = t++;
 }
 void dfs(int u,int sum)
 {
     int i,s=sum;
     if(sum>ans)
     return ;
     if(u==n)
     {
         ans = sum;
         return ;
     }
     for(i = head[u] ; i!= -; i = ed[i].next)
     {
         int v = ed[i].v;
         int tt = vis[v];
         if(p[u][v]<)
         {
             vis[v] = ;
             p[u][v]++;
             if(ed[i].d==u||ed[i].d==i||vis[ed[i].d])
             {
                 sum+=min(ed[i].w1,ed[i].w2);
             }
             else
             {
                 sum+=ed[i].w2;
             }
             dfs(v,sum);
             sum = s;
             p[u][v]--;
             vis[v] = tt;
         }
     }
 }
 int main()
 {
     int a,b,c,pp,r;
     while(scanf("%d%d",&n,&m)!=EOF)
     {
         init();
         memset(vis,,sizeof(vis));
         memset(p,,sizeof(p));
         ans = INF;
         while(m--)
         {
             scanf("%d%d%d%d%d",&a,&b,&c,&pp,&r);
             add(a,b,pp,r,c);
         }
         vis[] = ;
         dfs(,);
         if(ans!=INF)
         printf("%d\n",ans);
         else
         puts("impossible");
     }
     return ;
 }