Space Complexity of Radix Sort

[gaurav_13191]

I was just going through Radix Sort algorithm. Though I got the logic and the concept used in it, I am still pretty much confused about the space complexity being O(k+n) for this algorithm. (where, k is the max no of digits in a number, and n is the no. of inputs to be sorted). Any help will be appreciable. Thanks.

[rcgldr]

Did this radix sort algorithm create an array of histograms of [k] counts for how often each possible value for each digit occurred? If so, this would explain the O(k) part of the space complexity. The sort it self would also need at least a second temp array to store the results.