Alphabet patterns in python

problem 1:
sample input:5
sample output:
A
B C
D E F
G H I J
K L M N O
python code:
import string
x=string.ascii_uppercase
k=0
n=int(input())
for i in range(n):
    for j in range(i+1):
        print(x[k],end=' ')
        k+=1
    print('\r')   


problem 2:
sample input:5
sample output:
a
b c
d e f
g h i j
k l m n o

python code:

import string
x=string.ascii_lowercase
k=0
n=int(input())
for i in range(n):
    for j in range(i+1):
        print(x[k],end=' ')
        k+=1
    print('\r')


problem 3:
sample input:5
sample output:
A
B B
C C C
D D D D
E E E E E

python code:

import string
x=string.ascii_uppercase
k=0
n=int(input())
for i in range(n):
    for j in range(i+1):
        print(x[k],end=' ')
    k+=1
    print('\r')     


problem 4:
sample input:5
sample output:
a
b b
c c c
d d d d
e e e e e

python code:

import string
x=string.ascii_lowercase
k=0
n=int(input())
for i in range(n):
    for j in range(i+1):
        print(x[k],end=' ')
    k+=1
    print('\r')   


problem 5:print using format specifiers
sample input:5
sample output:
A
B B
C C C
D D D D
E E E E E

python code:

import string
x=string.ascii_uppercase
n=int(input())
for i in range(1,n+1):
    print('{} '.format(x[i-1])*i)


problem 6:
sample input:5
sample output:
A
C B
F E D
J I H G
O N M L K

python code:

import string
n=int(input())
x=string.ascii_uppercase
k=0
for i in range(n):
    l=[]
    h=''
    for j in range(i+1):
        l.append(x[k])
        k+=1
    l.reverse()
    h=' '.join(l)
    print(h)
       
problem 7:
sample input:5
sample output:
        a
      b c
    d e f
  g h i j
k l m n o

python code:

import string
n=int(input())
k=0
x=string.ascii_lowercase
for i in range(n):
    for j in range(n):
        if(i+j>=n-1):
            print(x[k],end=' ')
            k+=1
        else:
            print(' ',end=' ')
    print('\r')