我写了正确的spfa但是全wa了qaq？

#include<cstring>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<algorithm>
#include<queue>
using namespace std;
inline int read()
{
    register int X=0;register char ch=0;bool flag=0;
    for(;!isdigit(ch);ch=getchar()) if(ch=='-') flag=1;
    for(;isdigit(ch);ch=getchar()) X=(X<<3)+(X<<1)+ch-'0';
    return (flag ? -X : X);
}
inline void write(int x)
{
     if(x>9) write(x/10);
     putchar(x%10+'0');
}
int T=read(),n,m;
const int maxn=1e6;
struct edge
{
    int v,val,next;
}e[maxn<<1];
int head[maxn],tot,dis[maxn],cnt[maxn];
bool flag,vis[maxn];
deque <int> q;
void add(int u,int v,int val)
{
    e[++tot].v=v,e[tot].val=val,e[tot].next=head[u],head[u]=tot;
}
bool spfa(int s)
{
	for(int i=1;i<=n;i++) dis[i]=1000000000,head[i]=0,vis[i]=0,cnt[i]=0;
	dis[s]=0,vis[s]=1,cnt[s]=1,q.push_back(s);
	while(!q.empty())
	{
		int u=q.front();
		vis[u]=0;q.pop_front();
		for(int i=head[u];i;i=e[i].next)
		{
			int v=e[i].v;
			if(dis[v]>dis[u]+e[i].val)
			{
				dis[v]=dis[u]+e[i].val;
				cnt[v]=cnt[u]+1;
				if(cnt[v]>=n && e[i].val<0) return 1; 
				if(!vis[v])
				{
					if(dis[v]>dis[q.front()] || q.empty()) q.push_back(v);
					else q.push_front(v);
					vis[v]=1;
				}
			}
		}
	}
	return 0;
}
int main()
{
    while(T--)
    {
        tot=0;
        n=read(),m=read();
        for(int i=1;i<=m;i++)
        {
            int u=read(),v=read(),val=read();
            add(u,v,val);
            if(val>=0) add(v,u,val);
        }
        if(spfa(1))
            printf("YE5\n");
        else printf("N0\n");
    }
}