[WalterGR]

Would you be looking for the solution where you subtract every number in the array from 5050? If anyone says that they 99% studied it.

I was asked this exact question at my on-campus interview with one of the Big Five software companies for a Program Manager internshi between my 3rd and 4th years of college.

I had done no “leetcode grinding”-style prep.

Subtract from 5050? No, I didn’t think of that. But I did think of summing the numbers 1..100 with a for loop, sum the numbers in the input array, and subtract.

Not the perfect solution. But it’s O(n).

And I did get the internship.

My point being not that I’m some kind of algorithmic prodigy: I’m very much not. But if a college kid can solve it without any prep, nor rote memorization as GP suggests...