Luogu 3371（dijkstra堆优化）

传送门

模板题。再说一遍：dijkstra不能用入队标记。不是“不要”，是“不能”！！！

#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<queue>using namespace std;const int N=10004,M=500004;int n,m,S;int head[N],etot=0,dis[N];struct EDGE {int v,nxt,w;}e[M];struct Node {int id,dis;Node (int _id=0,int _dis=0):id(_id),dis(_dis) {}friend bool operator <(const Node &a,const Node &b) {return a.dis>b.dis;}};inline void adde(int u,int v,int w) {e[etot].nxt=head[u],e[etot].v=v,e[etot].w=w,head[u]=etot++;}inline int read() {int x=0;char c=getchar();while (c<'0'||c>'9') c=getchar();while (c>='0'&&c<='9') x=(x<<3)+(x<<1)+c-'0',c=getchar();return x;}inline int dijkstra(int S) {priority_queue<Node > q;while (!q.empty()) q.pop();memset(dis,0x3f3f3f3f,sizeof(dis));dis[S]=0,q.push(Node(S,0));while (!q.empty()) {Node cur=q.top();q.pop();for (int i=head[cur.id];~i;i=e[i].nxt) {int v=e[i].v;if (dis[v]>dis[cur.id]+e[i].w) {dis[v]=dis[cur.id]+e[i].w;q.push(Node(v,dis[v]));}}}}int main() {memset(head,-1,sizeof(head));n=read(),m=read(),S=read();for (int i=0;i<m;++i) {int u=read(),v=read(),w=read();adde(u,v,w);}dijkstra(S);for (register int i=1;i<=n;++i) printf("%d ",dis[i]^0x3f3f3f3f?dis[i]:2147483647);return 0;}