I have studied about finding LIS (longest increasing subsequence) How do I extend that knowledge to find LIS where gcd(xi, xi+1) > 1? Please help me here is the link to the question https://codeforces.com/problemset/problem/264/B
I have studied about finding LIS (longest increasing subsequence) How do I extend that knowledge to find LIS where gcd(xi, xi+1) > 1? Please help me here is the link to the question https://codeforces.com/problemset/problem/264/B
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Hint : The problem is related to prime factors. # of prime factors of $$$a_i$$$ is small.
Find prime factors by doing like "Sieve of Eratosthenes".
Hold largest length of sequence ever whose last element has the particular prime factor.
you mean this dp would work dp[i] = dp[i] + 1. where i is one of the primefactors of ith number. right? if yes then the maximum value of this array will be our answer?
No, (1) all dp[i] must be replaced with (2) (max of all dp[i])+1 where i is one of the primefactors. For example, when a=6, replace dp[2] and dp[3] with max(dp[2],dp[3])+1. This is because (1)[6 is a multiple of 2 and a multiple of 3], and (2)[we can put 6 after a multiple of 2 or a multiple of 3]. However, "max of dp array will be our answer" is right.
/* If you need, see my submission. */ Sorry my submission isn't fit the explanation.