List of Comments

Do not discard your own assumption: "Assume that there is only one duplicate number, find the duplicate one".

Input [2,2,2,2,2] 2 XOR 2 XOR 2 XOR 2 XOR 2 = 2 1 XOR 2 XOR 3 XOR 4 = 4 2 XOR 4 = 6

There is an O(1) space and O(n) runtime solution. XOR all numbers from 1 to n (inclusive) and XOR all numbers in the array. XOR both and you get the duplicate.

yes, it seems your solution is correct. I will correct this later.

For 5 pipes: (1, (2, (3, (4, 5)))) (1, (2, ((3, 4), 5))) (1, ((2, 3), (4, 5))) (1, ((2, (3, 4)), 5)) (1, (((2, 3), 4), 5)) ((1, 2), (3, (4, 5))) ((1, 2), ((3, 4), 5)) ((1, (2, 3)), (4, 5)) (((1, 2), 3), (4, 5)) ((1, (2, (3, 4))), 5) ((1, ((2, 3), 4)), 5) (((1, 2), (3, 4)), 5) (((1, (2, 3)), 4), 5) ((((1, 2), 3), 4), 5)

F(2)=1 F(3)=2 F(4)=5 F(5)=14 F(6)=42 F(7)=132 F(8)=429 F(9)=1430 F(10)=4862

how about f(4)?

Sorry, wrong calculation. I should not calculate by hand 😀 f(5) = 14 and f(6) = 42.

f(5) = 12 and f(6) = 35

What is your answer for 5 pipes and 6 pipes?

Let consider 5 pipes. Connect 1 to 2, call it a. Connect a to 3, call it b. Connect 4 to 5, call it c. Connect b and c. In my opinion there is no overlapping. If there is, please tell me where.

and you can only place the n+1 th pipe after n-th pipe.

f(1) = 0. the requirement is not to have overlapping connections.

In my opinion the solution is wrong. In the case of more than 4 pipes, you ignore the possibility to divide the pipes into two subsets of size k and n-k. Let f(k) be the number of possibilities to connect k pipes. Then when dividing as mentioned above, there are f(k) * f(n-k) different possibilities to connect the pipes. To find the correct answer we need to consider each possible partition of the pipes (such that they are continuous, that is only 1 to k and k+1 to n). For convenience lets define f(1) = 1. Then for n >= 2 the formula is f(n) = sum from k=1 to n-1 of f(k) * f(n-k).

thanks very good

thanks

just tried that, the multiple-monitor hint appears again. It is the second-to-right option in the top-bar.

yes, you are right, typos, corrected.

Hi, I am getting a bit confused here . Probably I am wrong, but shouldn't the condition be ? time - key.first >= 10 // then remove from queue and cache.

I must have answered incorrectly the first time, because I can't see any options now. Maybe I need to uninstall, then reinstall?

yes, it prompts the first time.

Does this prompt only happen once? I don't see an options to view or select any additional monitors on the system I am accessing.

Did you cleared the round? As after the phone interview they get back within 2 days. Best of luck.

I don't know what tools/algorithms Imagify use, but I trust jpegoptim since it is open source.

I am very interested to learn more about it. I learned about Imagify today and I am impressed with the results, and feedback I read over the Internet. What's your opinion about using Imagify to process the images directly in WordPress vs. using jpegoptim to optimize the images via command line? Could we get similar results than Imagify using jpegoptim? Any comparison, comments or advice?