What is the fastest way to sort 1 million integers when integers are from the range [1,100]?

Question

Notes: I\'ve thought about Radix sort, bucket sort, counting sort.

Is there anyway to achieve big O(n)?

Answer 1

Here is a counting sort in scala:

val res = Array.fill (100)(0)
val r = util.Random 
// generate data to sort
val nums = for (i <- 1 to 1000*1000) yield r.nextInt (100)
for (i <- nums) res(i) += 1
println (res.mkString (" "))