CLTZ - Collatz
Let N be a positive integer, Consider the following recurrence: f(1) = N and f(K) = (0.5 + 2.5 * (f(K-1) mod 2)) * f(K-1) + (f(K-1) mod 2) if K>1. For a given N you have to compute the smallest L for which f(L)=1 (such an L always exists for N's in the input).
Each line contains a positive integer N in decimal notation. You can be sure that N and all intermediate results are not bigger than 10^1888. Input terminated by EOF.
For each number N in the input print one line with the value of L in decimal notation.
Input: 1 2 321 1111111111111 111111111111111111111111111111111111111111111111111111111111 Output: 1 2 25 261 1296
Use python or java....it will make ur life easy
Punit Singh Koura:
can someone suggest some tricky test cases. I am getting wrong answer but i dont know why.
Last edit: 2013-07-10 16:51:37
Its from unproven Collatz conjecture. So probably there is no O(1) type solution.
i guess that brute force algorithm is enough for the problem.