PROBTRES  The 3n plus 1 problem V2
Background:
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.
The Problem:
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
It is conjectured that the algorithm above will terminate (when a 1 is printed) for any integral input value. Despite the simplicity of the algorithm, it is unknown whether this conjecture is true. It has been verified, however, for all integers n such that 0 < n < 1,000,000 (and, in fact, for many more numbers than this.)
Given an input n, it is possible to determine the number of numbers printed (including the 1). For a given n this is called the cyclelength of n. In the example above, the cycle length of 22 is 16.
For any two numbers i and j you are to determine the maximum cycle length over all numbers between i and j.
The Input:
The input will consist of a series of pairs of integers i and j, one pair of integers per line. All integers will be less than 1,000,000 and greater than 0.
You should process all pairs of integers and for each pair determine the maximum cycle length over all integers between and including i and j.
You can assume that no operation overflows a 32bit integer.
The Output:
For each pair of input integers i and j you should output i, j, and the maximum cycle length for integers between and including i and j. These three numbers should be separated by at least one space with all three numbers on one line and with one line of output for each line of input. The integers i and j must appear in the output in the same order in which they appeared in the input and should be followed by the maximum cycle length (on the same line).
Sample Input:
1 10
100 200
201 210
900 1000
Sample Output:
1 10 20
100 200 125
201 210 89
900 1000 174
hide comments
behzad_nouri:
20160218 02:49:36
The tests for this problem are **wrong**. You have to use **32bit Unsigned** integers to force overflow in order to pass the tests. also, mentioned in http://discuss.spoj.com/t/wa3n1problemprobtnpo/9780/2 Last edit: 20160218 02:50:07 

Eros Smith:
20140616 19:27:45
I am getting AC on simpler version and WA on this one using python 2.7. Anyone know what the issue might be considering the language is typeless? 

Mitch Schwartz:
20130804 02:58:36
Based on previous comments, you should be able to get AC with a 64bit container if you take only the 32 least significant bits after each operation (i.e. perform operations mod 2^32). Anyway, the problem is hidden. 

Raziman T V:
20130803 23:46:40
The assumption that intermediate values do not overflow 32 bit range is wrong. As a result, test data is faulty. Using unsigned int in c++ gives AC whereas using long long gives WA. 

Hossam ElDeen Goodname:
20130613 07:44:03
@Rahul:


Rahul:
20120920 07:31:57
how does the input terminate?


Adrian Maceiras:
20120905 01:57:34
Its that it doesnt overflow an unsigned int... java only provides signed int. 

Jakub ©afin:
20120201 14:06:23
also known as the Collatz sequence 

James Broman:
20120129 18:44:10
I am having issues with Java for V2. It is not getting accepted while I am able to get it working for V1.


Saurajit:
20120129 10:28:34
I'm having the same issue  I get AC for the simpler version, but WA for this one, even though I'm using unsigned long. 
Added by:  Coach UTN FRSF 
Date:  20090902 
Time limit:  0.377s3.779s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JS PERL 6 