CSP-201609-4 交通规划

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define pii pair<int,int>
 4 #define mp make_pair
 5 #define inf 0x3f3f3f3f
 6 const int maxn=10005;
 7 vector<pii>g[maxn];
 8 int N,M,d[maxn],f[maxn];
 9 bool vis[maxn];
10 int dij(){
11     memset(vis,0,sizeof(vis));
12     memset(d,inf,sizeof(d));
13     memset(f,inf,sizeof(f));
14     priority_queue<pii,vector<pii>,greater<pii> >q;
15     d[1]=0;
16     f[1]=0;
17     q.push(mp(0,1));
18     while(!q.empty()){
19         int u=q.top().second;q.pop();
20         if(vis[u])continue;
21         vis[u]=1;
22         for(int i=0;i<g[u].size();++i){
23             int v=g[u][i].first,w=g[u][i].second;
24             if(d[v]>d[u]+w){
25                 d[v]=d[u]+w;
26                 f[v]=w;
27                 q.push(mp(d[v],v));
28             }else if(d[v]==d[u]+w && f[v]>w){
29                 f[v]=w;
30             }
31         }
32     }
33 
34     int ans=0;
35     for(int i=2;i<=N;++i)ans+=f[i];
36     return ans;
37 }
38 int main(){
39     int a,b,c;
40     cin>>N>>M;
41     while(M--){
42         cin>>a>>b>>c;
43         g[a].push_back(mp(b,c));
44         g[b].push_back(mp(a,c));
45     }
46     cout<<dij()<<endl;
47     return 0;
48 }