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

itertools.permutations(iterable[, r]):

• This tool returns successive length permutations of elements in an iterable.

• If r is not specified or is None, then r defaults to the length of the iterable, and all possible full-length permutations are generated.

• Permutations are printed in a lexicographic sorted order. So, if the input iterable is sorted, the permutation tuples will be produced in sorted order.

Sample Code:

>>> from itertools import permutations
>>> print permutations(['1','2','3'])
<itertools.permutations object at 0x02A45210>
>>> 
>>> print list(permutations(['1','2','3']))
[('1', '2', '3'), ('1', '3', '2'), ('2', '1', '3'), ('2', '3', '1'), ('3', '1', '2'), ('3', '2', '1')]
>>> 
>>> print list(permutations(['1','2','3'],2))
[('1', '2'), ('1', '3'), ('2', '1'), ('2', '3'), ('3', '1'), ('3', '2')]
>>>
>>> print list(permutations('abc',3))
[('a', 'b', 'c'), ('a', 'c', 'b'), ('b', 'a', 'c'), ('b', 'c', 'a'), ('c', 'a', 'b'), ('c', 'b', 'a')]

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

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

Constraints: 

• 0 < k <= len(s)

• The string contains only UPPERCASE characters. 

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

Sample Input:

HACK 2

Sample Output:

AC
AH
AK
CA
CH
CK
HA
HC
HK
KA
KC
KH

Explanation :

All possible size 2 permutations of the string "HACK" are printed in lexicographic sorted order. 

Solution:

from itertools import permutations

word, num = input().split()

print(*[''.join(i) for i in permutations(sorted(word),int(num))],sep='\n')

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