WILLITST - Will it ever stop

When Bob was in library in University of Warsaw he saw on one of facades caption :"Will it ever stop?" and below some mysterious code:

while n > 1
  if n mod 2 = 0 then
    n:=n/2
  else
    n:=3*n+3

Help him finding it out !

Input

In first line one number n<=10^14.

Output

Print "TAK" if program will stop, otherwise print "NIE"

Example

Input:
4

Output:
TAK

Added by:Krzysztof Lewko
Date:2011-11-09
Time limit:0.906s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:AMPPZ 2011

hide comments
2020-06-24 21:22:23
Barely took me 4 mins
Others: using map to check repeating digits
Me: if it doesn't stop in 150 loops, it will never stop

AC in one go
2020-06-13 13:33:18
So I was printing "YAK" instead of "TAK" and it cost me 6 WAs.
Press F for me pls
2020-05-12 18:33:53
Those people who have used map and are getting WA in 20th case:
Use unsigned long long instead of long long.
2020-05-12 08:13:55
__builtin_popcount(n) betrayed me
2020-05-11 13:06:01
it is very simple,all numbers which are power of 2 i.e. 4,8,16,64,32,...... will only come to an end as they all end at 1.
but other any number will never end. take 3 or 6 or 62 such numbers and u will find they never end.
2020-04-25 10:21:45 Varun Goyal
Rather than following patterns, I think attempting to write proofs is a better technique to learn problem solving.

This proof is taken from user "meooow" on codechef:
https://discuss.codechef.com/t/problem-with-will-it-ever-stop-spoj-question/18320

The only step available to reduce a number is n->n/2 when n is even. Clearly if n = 2^k
then n is repeatedly halved by this step until it equals 1. However the other step is n->3*(n + 1)So if this step is carried out even once the new value is a multiple of 3. From there it can take either step but a it remains a multiple of 3. Thus it can never reach the form 2^k, which means it will never reduce to 1.

Last edit: 2020-04-25 10:26:49
2020-04-24 19:06:31



Last edit: 2020-04-24 19:06:46
2020-04-13 16:59:28
The constraint is a joke. Normal long long works.
2020-03-19 09:10:17
very easy...bit manipulation can also be used...
2020-03-16 12:46:44
sooo simple
© Spoj.com. All Rights Reserved. Spoj uses Sphere Engine™ © by Sphere Research Labs.