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CheezItMan
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Nov 14, 2019
CheezItMan
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CheezItMan
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Overall nice work, you hit the learning goals here. Well done. Check my comments below especially with regard to time/space complexity. Let me know if you have questions.
| # Space complexity: ? | ||
| # Time complexity: O(n) | ||
| # Space complexity: O(n) | ||
| def factorial(n) |
| def reverse(s, pointer = s.length - 1) | ||
| return s if s == "" | ||
| return s[pointer] if pointer == 0 | ||
| return s[pointer] + reverse(s, pointer - 1) |
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String concatenation creates a new array and copies all the individual elements over and so is O(n) by itself.
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the string | ||
| # Space complexity: O(n), where n is the length of the string | ||
| def reverse(s, pointer = s.length - 1) |
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👍
This works, but because you create a new array with each recursive call this is O(n2) for both time/space complexity.
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the string. (More precisely, n/2) | ||
| # Space complexity: O(n), where n is the length of the string. (More precisely, n/2) | ||
| def reverse_inplace(s, start = 0, finish = s.length - 1) |
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- This is not in place.
- This is the same time/space complexity as the method above.
| # Space complexity: ? | ||
| # Time complexity: O(n) | ||
| # Space complexity: O(n) | ||
| def bunny(n) |
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the string | ||
| # Space complexity: O(n), where n is the length of the string | ||
| def nested(s, parens_counter = 0, pointer = 0) |
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the string | ||
| # Space complexity: O(n), where n is the length of the string | ||
| def search(array, value, pointer = 0) |
| def is_palindrome(s, length = s.length, pointer = 0) | ||
| return true if pointer > length / 2 | ||
| return false if s[pointer] != s[length - 1 - pointer] | ||
| return is_palindrome(s, length, pointer + 1) if s[pointer] == s[length - 1 - pointer] |
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You shouldn't need the if here.
Suggested change
| return is_palindrome(s, length, pointer + 1) if s[pointer] == s[length - 1 - pointer] | |
| return is_palindrome(s, length, pointer + 1) |
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the string (More precisely, n/2) | ||
| # Space complexity: O(n), where n is the length of the string (More precisely, n/2) | ||
| def is_palindrome(s, length = s.length, pointer = 0) |
| raise NotImplementedError, "Method not implemented" | ||
| # Time complexity: O(n), where n is the length of the shorter string | ||
| # Space complexity: O(n), where n is the length of the shorter string | ||
| def digit_match(n, m, pointer = -1, matches = 0) |
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Sorry this is a bit late--catching up from a weekend out of town. Recursion is fun :)