//100，还是卡常 #include<bits/stdc++.h> using namespace std; #define int long long #define pii pair<int,int> #define fr first #define sc second #define mk make_pair #define pb push_back #define LD double int read(){int x=0,f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar();return x*f;} const int MAXN=100010; int n; LD ans; pii a[MAXN]; LD dis1(pii x,pii y){ return (LD)abs(x.fr-y.fr)+abs(x.sc-y.sc); } LD dis2(pii x,pii y){ return sqrt((x.fr-y.fr)*(x.fr-y.fr)+(x.sc-y.sc)*(x.sc-y.sc)); } bool cmp1(pii x,pii y){return x.fr+x.sc<y.fr+y.sc;} bool cmp2(pii x,pii y){return x.fr-x.sc<y.fr-y.sc;} void slv(){ ans=0; n=read(); for(int i=1;i<=n;i++)a[i].fr=read(),a[i].sc=read(); sort(a+1,a+n+1,cmp1); for(int i=1;i<n;i++){ ans=max(ans,dis1(a[i],a[i+1])*(LD)1.0/dis2(a[i],a[i+1])); } sort(a+1,a+n+1,cmp2); for(int i=1;i<n;i++){ ans=max(ans,dis1(a[i],a[i+1])*(LD)1.0/dis2(a[i],a[i+1])); } printf("%.10f\n",ans); } signed main(){ int _=read();while(_--) slv(); return 0; }