n=5 #Число строк
m=6 #Число столбцов
a=[random.sample(range(100),m) for i in range(n)]
for i in a:
print("max: "+str(max(i)))
#
for i in a:
i[0],i[-1] = i[-1],i[0]
print(a)
#---------
import numpy
tmp = m[:,0]
m[:,0] = m[:,-1]
m[:,-1] = tmp
#
for i in range(len(a)):
a[i][0], a[i][-1] = a[i][-1], a[i][0]