Itertools.permutations() (Python 3)

• URL : https://www.hackerrank.com/challenges/itertools-permutations/problem

• This tool returns successive r 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 a sorted order.

• Sample Code

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>>> 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.

문제풀이

• 단어s와 반복될 숫자n이 주어지면, 해당 단어를 n개의 조합으로 만들어서 출력하면됨
• n개의 조합은 itertools의 permutations를 사용하면 됨
• for문으로 해당 조합을 하나하나 뽑고, join을 이용하여 합침,
• 대신 s는 정렬이 되어있어야 해서 s를 sorted 시킨것을 출력함

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from itertools import permutations
s , n = input().split()

for i in list(permutations(sorted(s),int(n))):
    print(''.join(i))

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 HACK 2


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map(list,(permutations(s,int(i)))

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<map at 0x1c97d3d2808>

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