#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=2e6+10;
int t,n,m;
LL na,nb,a[N],b[N];
int main(){
	ios::sync_with_stdio(false);
	std::cin.tie(0);
	std::cout.tie(0);
	freopen("nzq.in","r",stdin);
	freopen("nzq.out","w",stdout);
	cin>>t;
	while(t--){
		cin>>n>>m;
		for(int i=1;i<=n;i++) a[i]=b[i]=0;
		na=nb=0;
		int f=0;
		for(int i=1;i<=m;i++){
			int o,x;
			cin>>o>>x;
			if(o==1){
				if(a[x]==0) a[x]=1,na++;
				if(a[x]==1&&b[x]==1){f=1;cout<<i<<endl;break;}
				if(na>=n){f=1;cout<<i<<endl;break;}
			}else{
				if(b[x]==0) b[x]=1,nb++;
				if(a[x]==1&&b[x]==1){f=1;cout<<i<<endl;break;}
				if(nb>=2){f=1;cout<<i<<endl;break;}
			}
			if(nb>=2){f=1;cout<<i<<endl;break;}
			if(na>=n){f=1;cout<<i<<endl;break;}
		}
		if(f==0) cout<<"-1\n";
	}
	return 0;
} 

莫名其妙的WA

代码应该比较通俗