Prompts

The Collatz conjecture is a conjecture in mathematics that concerns a sequence defined as follows: start with any positive integer n. Then each term is obtained from the previous term as follows: if the previous term is even, the next term is one half the previous term. If the previous term is odd, the next term is 3 times the previous term plus 1. The conjecture is that no matter what value of n, the sequence will always reach 1.

Given positive integer n, return a list of the of the Collatz sequence from n to 1. Recursive and iterative.

3 -> [3, 10, 5, 16, 8, 4, 2, 1]

Given positive integer n, return the number of steps required to go from n to 1. Recursive and iterative.

3 -> 7

Given positive integer n, return a list of length n where each 1-index is the number of steps required for that number to reach 1. Recursive and iterative

4 -> [0, 1, 7, 4]

The Fibonacci numbers form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1.

Return a list of the first n numbers of the Fibonacci sequence. Recursive and iterative.

0 -> []

1 -> [0]

4 -> [0, 1, 1, 2]

Return the nth (0 index) number of the Fibonacci sequence. Recursive and iterative.

0 -> 0

9 -> 21

Return the greatest Fibonacci number less than or equal to n. Recursive and iterative.

12 -> 8

13 -> 13

Given a whole number, return if that number is a Fibonacci number. Recursive and iterative.

1 -> True

4 -> False

Given a whole number n, return a list of n+1 booleans where each item in the list represents if its 0-index is a Fibonacci number.

6 -> [True, True, True, True, False, True, False]

Given a string, return a new string keeping only the first occurrence of each character in order.

'caardc' -> 'card'

Given a string, return a new string keeping only the first two occurrences of each character in order.

'abacbabbcd' -> 'abacbcd'

Given a string, return a new string keeping only the last occurrence of each character in order.

'caardc' -> 'card'

Given a dictionary, reverse the keys and value in place. Keys and values are disjoint sets.

{'a': 0, 'b': 1} -> {0: 'a', 1: 'b'}