| def get_odd_collatz(n): | |
| """ | |
| Given a positive integer n, return a sorted list that has the odd numbers in collatz sequence. | |
| 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 of | |
| 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. | |
| Note: | |
| 1. Collatz(1) is [1]. | |
| 2. returned list sorted in increasing order. | |
| For example: | |
| get_odd_collatz(5) returns [1, 5] # The collatz sequence for 5 is [5, 16, 8, 4, 2, 1], so the odd numbers are only 1, and 5. | |
| """ | |
| if n%2==0: | |
| odd_collatz = [] | |
| else: | |
| odd_collatz = [n] | |
| while n > 1: | |
| if n % 2 == 0: | |
| n = n/2 | |
| else: | |
| n = n*3 + 1 | |
| if n%2 == 1: | |
| odd_collatz.append(int(n)) | |
| return sorted(odd_collatz) | |