堆优化的dij【模板】

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<queue>
 using namespace std;
 int head[],n, m, cnt, ccnt;
 long long dist[],ans;
 struct pot {
     int id;
     int val;
     bool operator<(const struct pot&aa)const {
         return val > aa.val;
     }
 };
 struct edge {
     int fr;
     int to;
     long long  v;
     int next;
 }e[];
 void INIT() {
     memset(head, -, sizeof(head));
     memset(dist, 0x3f3f3f3f, sizeof(dist));
     dist[] = ;
     cnt=;
     ans = ;
 }
 void adde(int xx, int yy,long long zz) {
     e[cnt].fr = xx;
     e[cnt].to = yy;
     e[cnt].v = zz;
     e[cnt].next = head[xx];
     head[xx] = cnt++;
 }
 void dij() {
     priority_queue<struct pot>pq;
     struct pot sta;
     sta.id = ;
     sta.val = ;
     pq.push(sta);
     while (!pq.empty()) {
         struct pot aa = pq.top(); pq.pop();
         if (dist[aa.id] < aa.val)continue;
         for (int i = head[aa.id]; i != -; i = e[i].next) {
             if (dist[e[i].to] > dist[aa.id] + e[i].v) {
                 dist[e[i].to] = dist[aa.id] + e[i].v;
                 struct pot cc;
                 cc.id = e[i].to;
                 cc.val = dist[e[i].to];
                 pq.push(cc);
             }
         }
     }
 }
 int main() {
     int t;
     scanf("%d",&t);
     while (t--) {
         INIT();
         scanf("%d%d", &n, &m);
         while (m--) {
             int x, y;
             long long z;
             scanf("%d%d%lld", &x, &y, &z);
             adde(x, y, z);
         }
         dij();
     }
     return ;
 }