710 B | 710 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
# sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
n = ii()
l = [mii() for _ in range(n)]
z = set()
for i in l:
k = []
for j in i:
k.append(j - i[0])
z.add(tuple(k))
return len(z) == 1
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()
p(f"{t}. {'YES' if ret else 'NO'}")