CCF-交通规划

#include<cstdio>
#include<queue>
#include<vector>
#define maxn 100005
#define inf 0x7fffffff
int n,m;
using namespace std;
struct Point
{
int u;
int dist;
Point(int uu,int d){
u=uu,dist=d;
}
friend bool operator < (Point a,Point b) {
return a.dist > b.dist;
}
};
struct Edge
{
int v;
int cost;
Edge(int vv,int c){
v=vv,cost=c;
}
};
vector<Edge> G[maxn];
bool vis[maxn];
int disto[maxn];
int costo[maxn];

void Dijkstra(int s)
{
for(int i=1;i<=n;i++){
vis[i]=false;
disto[i]=costo[i]=inf;
}
disto[s]=0;
costo[s]=0;
priority_queue<Point> queue;
queue.push(Point(s,0));
while(!queue.empty()){
Point p=queue.top();
queue.pop();
int u=p.u;
if(!vis[u]){
for(int i=0;i<G[u].size();i++){
int v=G[u][i].v;
int co=G[u][i].cost;
if(!vis[v]){
if(disto[v]>disto[u]+co){
disto[v]=disto[u]+co;
queue.push(Point(v,disto[v]));
costo[v]=co;
}
if(disto[v]==disto[u]+co){
costo[v]=min(costo[v],co);
}
}
}
}
}
}
int main()
{
int u,v,c;
scanf("%d%d",&n,&m);
while(m--){
scanf("%d%d%d",&u,&v,&c);
G[u].push_back(Edge(v,c));
G[v].push_back(Edge(u,c));
}
Dijkstra(1);
int ans=0;
for(int i=2;i<=n;i++)
ans+=costo[i];
printf("%d",ans);
}