The 3n + 1 problem is a popular program from UVa online judge, I have solved it using python .

Problem Description

Problems in Computer Science are often classified as belonging to a certain class of problems (e.g., NP, Unsolvable, Recursive). In this problem you will be analyzing a property of an algorithm whose classification is not known for all possible inputs.

Consider the following algorithm:

1. input n

2. print n

3. if n = 1 then STOP

4. if n is odd then n ← 3n + 1

5. else n ← n/2

6. GOTO 2

Given the input 22, the following sequence of numbers will be printed

22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1

For More details about the problem visit : The 3n + 1 problem

@functools.lru_cache(None) To Know details about it visti: https://docs.python.org/3/library/functools.html

Sample Input 

1 10 
100 200 
201 210 
900 1000

Sample Output 

1 10 20 
100 200 125 
201 210 89 
900 1000 174

If you got any better solution let me know in the comment box bellow.