CCF-交通规划

来源：互联网发布：手机透镜桌面软件编辑：程序博客网时间：2024/04/29 11:00
#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);}
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