20求条必关

#include<bits/stdc++.h>
using namespace std;
long long t,n,m,a[200001],p[200001],xx;
bool f;
signed main() {
	// freopen("sequence.in","r",stdin);
	// freopen("sequence.out","w",stdout);
	cin>>t;
	while(t--) {
		f=1;
		cin>>n>>m;
		for(int i=1; i<=m; i++) cin>>p[i]>>xx,a[p[i]]=xx;
		if(m==0||m==1) cout<<"Yes\n";
		else {
			sort(p+1,p+1+m);
			xx=((p[2]-p[1]==0)?0:(a[p[2]]-a[p[1]])/(p[2]-p[1]));
			for(int i=2; i<m; i++)
				if(a[p[i+1]]!=a[p[1]]+(p[i+1]-p[1])*xx) {
					cout<<"No\n";
					f=0;
					break;
				}
			if(f) cout<<"Yes\n";
		}
	}
	return 0;
}