Problem ID | 3np1 |
---|---|
Difficulty level (0..10) | 3 |
Maximum runtime | 1 minute |
Original problem | |
Seen at | Internet Contest 90 |
The 3n+1 problem
Using the following algorithm:
Input will consist of pairs of i and j, one pair at a line. i and j will be
less than 10000 and greater than 0. At the output i and j with the
maximum cycle-length of all integers between and including i and j
pairs should be printed. One line for each pair. i and j should be
printed in the same order as in
the input. No trailing or leading spaces. No more than one space between the
output numbers.
Sample input:
Sample output:
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 number i.e. 22 we have:
in 16 steps. 16 is the cycle length of 22.
For any i and j one can find the maximum cycle-length of all the numbers
between and including i and j.
22 11 34 17 52 26 13 40 20 10 5 16 8 4 2 1
1 10
100 200
201 210
900 1000
1 10 20
100 200 125
201 210 89
900 1000 174