[Programmers] Disguise

https://programmers.co.kr/learn/courses/30/lessons/42578

Solution

This is a problem where you need to calculate the number of combinations for clothing types. Since the clothing type is stored in the second element of each item in the clothes list, I create keys based on those values.

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from collections import defaultdict
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def solution(clothes):
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    answer = defaultdict(int)
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    for cloth in clothes:
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        answer[cloth[1]] += 1
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    cnt = 1
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    for key in answer:
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        cnt *= answer[key] + 1
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    return cnt - 1

answer stores how many items exist per clothing type. When computing the combinations, I add 1 to each answer[key] because there’s also the case of not wearing that type at all.

Since wearing nothing at all is one of the counted cases, subtracting 1 from cnt gives the number of valid outfits.

Code

https://github.com/naem1023/codingTest/blob/master/hash/pg-30-42578.py