I was trying to solve an exercise while studying basic probabilities and while solving the exercise, I thought of this problem which I thought was fun, so I decided to share it with my fellow noobs :)

Please if you're anything above a newbie, (in Ercole Visconti's voice) This problem is not for you (no offence) :)

**Problem Statement**

You have n tiles numbered from 1 through to n. You are also given an integer K. The task it to count all pairs of integers (a,b) from the n tiles whose difference is K. that means (a — b) = K

**Input** The one and only line of the input contains two positive integer n and K. **Output** Print the number of such pairs (a, b) whose difference is K, thank you.

**Sample input** 100 11 **Sample output** 89

n-k ?)

Lolzzzz, I'm such a dumb a**.... My actual solution was (n — (k+1)) + 1

Didn't realize it was that simple honestly.

max(n — k, 0) ?

I think that is good for problem A of Div4.

Answer = $$$\max(\frac{(n-k)^2}{n-k}, \lim_{x\rightarrow\infty}\frac{3x}{2x^2})$$$

Sadly, your solution will receive a runtime error when n=k :)

Easy, to avoid division by zero, just add another limit:

.

Spoiler