Math logic to substitute if statement - objective-c

Question

The below code works, but I'm trying to come up with some math logic and use some binary operator to put in place of this if statement.
NSInteger indexCor = 0;
for (PFObject *object in self.objects) {
if (object == custom) {
if (indexCor < 2) {
NSLog(#"rodou indexCor <=2.");
[self.coresConjugadosDict setObject:self.uiColorsArray[0] forKey:object.objectId];
indexCor++;
}
else if (indexCor < 4) {
[self.coresConjugadosDict setObject:self.uiColorsArray[1] forKey:object.objectId];
indexCor++;
}
else if (indexCor < 6) {
[self.coresConjugadosDict setObject:self.uiColorsArray[2] forKey:object.objectId];
indexCor++;
}
else if (indexCor < 8) {
[self.coresConjugadosDict setObject:self.uiColorsArray[3] forKey:object.objectId];
indexCor++;
}
else if (indexCor < 10) {
[self.coresConjugadosDict setObject:self.uiColorsArray[4] forKey:object.objectId];
indexCor++;
}
else if (indexCor < 12) {
[self.coresConjugadosDict setObject:self.uiColorsArray[5] forKey:object.objectId];
indexCor++;
}
else {
[self.coresConjugadosDict setObject:self.uiColorsArray[6] forKey:object.objectId];
indexCor++;
}
}
So basically, some objects are going to be combined with another object. What I need to do is to set one UIColor for each group of two combined objects. I have a NSArray with the UIColors I want to use, and right now, what happens is that each object that meets the specific criteria I add the first color in the array, increment it. This way, each group of two objects will be of a different color.
So, if have 6 objects...
Objects 1,2 = Color 1 Objects 3,4 = Color 2 Objects 5,6 = Color 3
and so on.
I would like to achieve this without the if statement.

Answer 1

It looks like you'd like to make these transformation:
indexCor uiColorsArray index
-------- -------------------
0, 1 0
2, 3 1
4, 5 2
6, 7 3
8, 9 4
10, 11 5
12 and up 6
This can be achieved by integer-dividing indexCor by 2, and limiting the result to 6, like this:
[self.coresConjugadosDict
setObject:self.uiColorsArray[min(indexCor++/2, 6)]
forKey:object.objectId];
Note: you may need to define your own min function to use the above code; the code above will not work correctly with a simple MIN macro, unless you move indexCor++ on a separate line.
Demo of the concept on ideone.