Clarification on input size with online judge

general
,
1

Hello, actually I’m comfort with TC and SC and it’s calculation for algorithms.

In most of problems I’m seeing this:
An input array of length ‘n’, where 1<=n<=3*10e4.

From my previous learning, I learnt that generally a computer executes 10e8 operations in 1sec. If I has my algo which is Big O(n), then max operations of my algo will be 310e4 , which is significantly less than 10e8. If my algo is Big O(nn), then it will take 9*10e8, which is not efficient and may get TLE.

So, my question is, does every IDE or online judge like codechef, leetcode, codeforce also executes 10e8 instructions in 1sec and follow the above rule (or) does it varies? While solving a problem in codechef, I written a O(n) solution for max input size of 10e6, though I’m getting TLE? Why is these ? Please give some clarity on these ! Thankyou.

You can see the problem and solution which I’m discussing here : See the problem and solution

2

The not in Operation is suppose to take 0(n) time in your code, so the time complexity of your code is O(n*n) which will TLE.

3

Hey, I used not in operation to look up in a dictionary. So, Lookup in dictionary or hashmap will take O(1) right ? Correct me if I’m wrong, thanks you.