【luogu P3371 单源最短路径】 模板 dij + heap

题目链接：https://www.luogu.org/problemnew/show/P3371#sub

堆优化迪杰斯特拉，留着以后复习用

 #include <iostream>
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <queue>
 using namespace std;
 const int inf = ;
 const int maxn = ;
 struct Edge{
     int u,v,w;
 }e[maxn];
 struct Point{
     int na,s;
 }dis[maxn];
 struct cmp{
     bool operator ()(Point &a,Point &b){
         return a.s>b.s;
     }
 };
 priority_queue<Point,vector<Point>,cmp> q;
 int m, n, sta;
 int head[maxn];
 bool vis[maxn];
 int main()
 {
     scanf("%d%d%d",&n,&m,&sta);//n 点  m 边
     for(int i = ; i <= m; i++)
     {
         int x,y,z;
         scanf("%d%d%d",&x,&y,&z);
         e[i].u = y;
         e[i].v = head[x];
         e[i].w = z;
         head[x] = i;
     } 

     for(int i = ; i <= n; i++)
     {
         dis[i].na = i;
         dis[i].s = inf;
     }

     dis[sta].s = ;
     int now = ;
     vis[] = ;
     q.push(dis[sta]);

     for(int k = ; k < n; k++)
     {
         while(vis[now])
         {
             now = q.top().na;
             q.pop();
         }
         vis[now] = ;
         int c = head[now];
         while(c)
         {
             int mu = e[c].u;
             if(dis[mu].s > dis[now].s+e[c].w)
             {
                 dis[mu].s = dis[now].s+e[c].w;
                 q.push(dis[mu]);
             }
             c = e[c].v;
         }
     }
     for(int i = ; i <= n; i++)
     printf("%d ",dis[i].s);
     return ;
 }