A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is even or 3n+1 if the number is odd. See Problem 21 for more information.
Let c(n) be the sequence for n, and p(n) be the peak value of that sequence. For a given threshold nmax, find the highest peak value max(p(n)) for all Collatz sequences starting with integers between 1 and nmax.
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Nice one
Good problem!
good.
If you want to add more tests: https://oeis.org/A006884 and https://oeis.org/A006885 contain the relevant sequences.
Why the leading solution size is 0 ? Is it for everyone or just me
@Tanzil Parvez (Emon): the hack solutions (hopefully all) have been deleted from this problem.
Wrong test cases! I checked on internet and found all the test cases except case 1 are wrong.
The test cases are all correct. You have simply not understood what the question is asking.
Broken link in description.
Link has been updated.
why does it not work it can run successfully in matalb
function pmax = peakOfPeaks(nmax)
B=[]
for n=1:1:nmax
A=[];
if n==1
A=1
else A=n
end
while n~=1
if mod(n,2)==1
A=[A,3*n+1];
n=3*n+1
else A=[A,n/2];
n=n/2
end
end
B=[B,max(A)]
end
pmax=max(B)
end