Practice>Python>Itertools>Iterables and Iterators

Iterables and Iterators

Problem link : https://www.hackerrank.com/challenges/iterables-and-iterators/problem

Difficulty : Medium

Tip

• As we can see from problem description, it's regarding combination
• We might be confused a bit due to that 'a' is appeared only once, or multiple
• If 'a' appeared only once, we can resolve it simply
• However, a appeared in multiple times
• we should generate all combination
• and check each one have 'a' or not
• Don't worry, combonation in itertools, will generate all of possible combination

Solution

from itertools import combinations input() items = input().split(' ') items = ''.join(items) n = int(input()) combs = combinations(items, n) combs = list(combs) cnt = 0 for item in combs: if 'a' in item: cnt += 1 cntAll = len(combs) print(cnt/cntAll)