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https://www.educative.io/courses/grokking-the-coding-interview/xVlKmyX542P

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#1

https://www.educative.io/courses/grokking-the-coding-interview/xVlKmyX542P

Mistake on Time and Space complexity? Looks like these permutations are 2N instead of 2^N. So Time Complexity would be O(N2N) and Space Complexity O(2N) isn’t it? If the input is ab7c our outpull will contains 24 (being N the size of the string)

#2

Every time we change the character’s case we multiply current space size by two. And the worst case would be string consisting only of letters giving the time/space complexity are O(N* 2^N).