Given an array of numbers it might be possible to compress it by looking for repeating numbers in the sequence.
If there are enough repeating numbers in the sequence then then a new array should be generated where each value is represented by a pair of values instead. The first value is the actual array value and the second is the number of times it repeats.
For example:

data[] = {1,1,1,2,2,3,3}

can be compressed into

data[] = {1,3,2,2,3,2}

which uses one fewer elements.
And the array

data[] = {1,1,1,2,2,3}

can be compressed into

data[] = {1,3,2,2,3,1}

but since it isn't any smaller it should be left alone!
Either return the compressed array if it is smaller than the original but otherwise just return the orginal