HackerRank Python Solution - Itertools Topic - itertools.combinations()

itertools.combinations(iterable, r):

• This tool returns the length subsequences of elements from the input iterable.

• Combinations are emitted in lexicographic sorted order. So, if the input iterable is sorted, the combination tuples will be produced in sorted order.

Sample Code:

>>> from itertools import combinations
>>> 
>>> print list(combinations('12345',2))
[('1', '2'), ('1', '3'), ('1', '4'), ('1', '5'), ('2', '3'), ('2', '4'), ('2', '5'), ('3', '4'), ('3', '5'), ('4', '5')]
>>> 
>>> A = [1,1,3,3,3]
>>> print list(combinations(A,4))
[(1, 1, 3, 3), (1, 1, 3, 3), (1, 1, 3, 3), (1, 3, 3, 3), (1, 3, 3, 3)]

Task: You are given a string S. Your task is to print all possible combinations, up to size k, of the string in lexicographic sorted order.

Input Format: A single line containing the string S and integer value k separated by a space.

Constraints: 

• 0 < k < len(s)

• The string contains only UPPERCASE characters. 

Output Format: Print the different combinations of string S on separate lines.

Sample Input:

HACK 2

Sample Output:

A
C
H
K
AC
AH
AK
CH
CK
HK

Solution:

from itertools import combinations

word, num = input().split()

for i in range(1, int(num)+1):
    for j in combinations(sorted(word), i):
        print(''.join(j))
        

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