The 3n + 1 problem |

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. inputn2. print

n3. if

n= 1 then STOP4. if

nis odd then5. else

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 *cycle-length* 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 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*.

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).

1 10 100 200 201 210 900 1000

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