### aryan57's blog

By aryan57, history, 2 years ago, I was solving this question https://codeforces.com/contest/1132/problem/F using the editorial's method.
Only difference is, I was using iterative dp rather than recursive dp.

My submission https://codeforces.com/contest/1132/submission/114519575
Copy pasted editorial submission https://codeforces.com/contest/1132/submission/114519641

I thought N=500 will give TLE in a O(N^3) solution, however it passed and in less time than the editorial's solution which I think is in O(N^2).

Why is it so? Also, is the editorial solution really O(N^2) or am I wrong? What should be the constraints on N to pass a O(N^3) solution as a general rule of thumb? Comments (4)
 » Auto comment: topic has been updated by aryan57 (previous revision, new revision, compare).
 » Both of the solutions are O(N^3). The only reason your is faster because it has better constants then recursive solution.As per my experience N=500 is usually the upper limit for 0(N^3) to work.
 » One important thing to notice is that the time limit is 3 secs for that problem, so O(N^3) would easily pass as operations would be less than 3e8
 » 2 years ago, # | ← Rev. 2 →   It depends a lot from the task. Maybe $500$ for some recursive dp, maybe $5000$ for matrix multiplication by modulo $2$.My implementation of bit matrix multiplication fits in $0.9s$ on CF with $N = 5000$.