dij+堆优化求单源最短路以及其模板

 

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#include<bits/stdc++.h>
using namespace std;
const int maxn=1e6;
int cnt=0,n,m,s,dis[maxn],vis[maxn],head[maxn];
struct mad{
    int to,val,next;
}edge[maxn];
struct lys
{
    int point,val;
    bool operator > (const lys tmp)const{
        return val>tmp.val;
    }
};
void add(int a,int b,int val)
{
    cnt++;
    edge[cnt].to=b;
    edge[cnt].val=val;
    edge[cnt].next=head[a];
    head[a]=cnt;
}
priority_queue<lys,vector<lys>,greater<lys> > q;
void dij(int s)
{
    lys son;
    son.point=s;
    son.val=0;
    //vis[s]=1;
    memset(dis,0x7f,sizeof(dis));
    dis[s]=0;
    
    q.push(son);
    
    while(!q.empty())
    {
        lys son=q.top();
        q.pop();
        
        int x=son.point,e=son.val;
        if(vis[x])
        {
            continue;
        }
        
        vis[x]=1;
        
        for(int i=head[x];i;i=edge[i].next)
        {
            if(dis[edge[i].to]>dis[x]+edge[i].val&&!vis[edge[i].to])
             {
                  dis[edge[i].to]=e+edge[i].val;
                  son.point=edge[i].to;
                  son.val=dis[edge[i].to];
                  q.push(son);
                  //printf("%d %d\n",son.point,son.val);
             }
        }
    }
}
int main()
{  // freopen("lyslyslys.in","r",stdin);

    cin>>n>>m>>s;
    for(int i=1;i<=m;i++)
    {
        int a,b,c;
        cin>>a>>b>>c;
        add(a,b,c);
    }
    dij(s);
    for(int i=1;i<=n;i++)
    {
        printf("%d ",dis[i]);
    }
}