Lang:G++
Edit12345678910111213141516171819202122232425262728293031#include<cstdio>#include<cstring>typedef unsigned int uint;inline void read(short &res){static char ch;register short flag=1;while((ch=getchar())<'0'||ch>'9')if(ch=='-')flag=-1;res=ch-48;while((ch=getchar())>='0'&&ch<='9')res=res*10+ch-48;res*=flag;}const short maxn=509;short n,m,t,p[maxn],vis[maxn];short find(short x){return x==p[x]?x:p[x]=find(p[x]);}int main(){read(t);while(t--){read(n),read(m);for(register int i=0;i<=n;i++)p[i]=i;short a,b,edge=0,v=0,flag=0,x,y;memset(vis,0,sizeof(vis));while(m--){read(a),read(b);if(a==0&&b==0)puts("YES");if(a==b){flag=1;continue;}else{if(!vis[a]){vis[a]=1;v++;}if(!vis[b]){vis[b]=1;