A formula that returns the greater of two variables

Question

This isn't specific to any particular programming language, although I happen to be working in JavaScript.

I am trying to create a mathematical formula that results in the higher of the two variables without using a comparison operator.

Example:
X = 10;
Y = 14;

In JavaScript you can use `Math.max()`, like this: `Math.max(X, Y)`. — Azametzin, Mar 16 '20 at 23:08
Cross language dup: https://stackoverflow.com/q/4772780/2422776 — Mureinik, Mar 16 '20 at 23:09
It was a puzzle presented to me and I am trying to figure it out. It doesn't seem I have enough information to do this but I'm told it can be done. — Jonathan Marshall, Mar 16 '20 at 23:09
What are the rules of the puzzle? What counts as a comparison operator, and are you allowed to use built-in functions that do comparisons internally? What operations *are* allowed? — kaya3, Mar 16 '20 at 23:10

Picaud Vincent · Answer 1 · 2020-03-17T06:18:24.633

0

For positive numbers or if you are only interested by magnitude (see comment below), you can use:

max(x,y)=(|x+y|+|x−y|)/2

You can also compute min with:

min(x,y)=(|x+y|-|x−y|)/2

edited Mar 17 '20 at 06:18

answered Mar 16 '20 at 23:09

Picaud Vincent

1

Your solution says that the maximum of -1 and -3 is positive 3. – kaya3 Mar 16 '20 at 23:14
@kay3 opss, you are 100% right, this only works for positive numbers, thank you! I fixed my post – Picaud Vincent Mar 17 '20 at 06:16

1 Answers1