Best method to find sum of x for three numbers.

[Gamebot]

If I add three posative numbers to equal 19, keeping in mind 19 can be any number, I would like to know the best way to accomplish this for all possible numbers.

As of right now I have three for loops that simply check if: I + J + K = x. When x in this case is 19. It works fine and numbers wont go over 30 for my use. I have to wonder if checking that many values is the best way of doing it.

Thought someone with much better math skills especially in programming might have a better answer.

 

[obscene]

Your computer does not see 3 values and think, "whoa, that's a lot of values." It's pretty good at math. Addition is it's favorite.

But what are three for-loops about? If there's a better way at all, we'd have to see all the relevant code.

 

[TheouAegis]

Is each number unique? So that no two numbers could be the same, such as the set [5,9,5]? Do you care what order the numbers are in (in other words, if it finds [4,5,10], should it ignore [4,10,5] and other such combos)? Right now your code finds all permutations. Or are you just trying to pick 3 numbers at random and see if they add up to the target value? Or are you trying to, say, have 5 numbers chosen at random such that only 3 of them can possibly add up to the target value?

 

[FrostyCat]

If you just want 3 random positive integers to add up to a target value, there's a one-shot way to do that:

i = irandom_range(1, n-2);
j = irandom_range(1, n-1-i);
k = n-i-j;

 

[Gamebot]

I really need to learn how to explain myself better.

I need all possibilities in sequence as it is for looking up values within a 3d grid. (Still working a few things out)

I did figure out I needed to change the formula a bit. Because I should have known better.

Instead of this:
a + b + c = x

I need:
b + c - a = x

Therfore with a 5 x 5 grid looking up all values for the number 3. I would have:

113
122
131
214
223
.
.
544

It should be in that order also.
Loops will work fine for now.