用自己写的队列（提交记录）：

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=2e3+10,M=6e3+10;
int head[N],e_cnt=0;
struct EDGE{int to,pre,w;}e[M];
void add_edge(int from,int to,int w){
    e[++e_cnt]=EDGE{to,head[from],w};
    head[from]=e_cnt;
}
struct my_que{
    int val[N],head=1,tail=1;
    void push(int x){val[tail++]=x;}
    void pop(){head++;}
    int top(){return val[head];}
    int size(){return tail-head;}
    bool empty(){return tail-head==0;}
    void clr(){head=1,tail=1,memset(val,0,sizeof(val));};
}que; 
int T,n,m,dis[N],len[N];
bool book[N];
void init(){
    for(int i=1;i<M;i++)e[i]=EDGE{0,0,0};
    e_cnt=0;
    memset(head,0,sizeof(head));
    memset(dis,0x3f,sizeof(dis));
    memset(len,0,sizeof(len));
    memset(book,0,sizeof(book));
    que.clr();
}
bool spfa(){
    que.push(1),dis[1]=0,book[1]=1;
    while(!que.empty()){
        int u=que.top();
        que.pop();
        book[u]=0;
        for(int i=head[u];i;i=e[i].pre){
            int v=e[i].to,w=e[i].w;
            if(dis[v]>dis[u]+w){
                dis[v]=dis[u]+w;
                len[v]=len[u]+1;
                if(len[v]>=n)return true;
                if(!book[v])que.push(v),book[v]=1;
            }
        }
    }
    return false;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    cin>>T;
    while(T--){
        init();
        cin>>n>>m;
        for(int i=1;i<=m;i++){
            int u,v,w;
            cin>>u>>v>>w;
            add_edge(u,v,w);
            if(w>=0) add_edge(v,u,w);
        }
        if(spfa())cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}

然后把自己写的换成 STL 的 queue 就能过

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=2e3+10,M=6e3+10;
int head[N],e_cnt=0;
struct EDGE{int to,pre,w;}e[M];
void add_edge(int from,int to,int w){
    e[++e_cnt]=EDGE{to,head[from],w};
    head[from]=e_cnt;
}
queue<int>que; 
int T,n,m,dis[N],len[N];
bool book[N];
void init(){
    for(int i=1;i<M;i++)e[i].pre=0;;
    e_cnt=0;
    memset(head,0,sizeof(head));
    memset(dis,0x3f,sizeof(dis));
    memset(len,0,sizeof(len));
    memset(book,0,sizeof(book));
}
bool spfa(){
    que.push(1),dis[1]=0,book[1]=1;
    while(!que.empty()){
        int u=que.front();
        que.pop();
        book[u]=0;
        for(int i=head[u];i;i=e[i].pre){
            int v=e[i].to,w=e[i].w;
            if(dis[v]>dis[u]+w){
                dis[v]=dis[u]+w;
                len[v]=len[u]+1;
                if(len[v]>=n)return true;
                if(!book[v])que.push(v),book[v]=1;
            }
        }
    }
    return false;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    cin>>T;
    while(T--){
        init();
        cin>>n>>m;
        for(int i=1;i<=m;i++){
            int u,v,w;
            cin>>u>>v>>w;
            add_edge(u,v,w);
            if(w>=0) add_edge(v,u,w);
        }
        if(spfa())cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}