Update countingsort.lua

Author: icemberg

src/sorting/countingsort.lua

@@ -4,12 +4,10 @@ return function(
     -- key_function to map elements to integer keys, defaults to identity
     key_function
 )
-    -- Default to identity function if no key_function is provided
-    key_function = key_function or function(x) return x end
-
-    -- Handle empty list case
     if list[1] == nil then return end
 
+    key_function = key_function or function(x) return x end
+
     -- Find the range of keys (min_key and max_key)
     local min_key, max_key = math.huge, -math.huge
     for _, elem in ipairs(list) do
@@ -18,7 +16,6 @@ return function(
         max_key = math.max(max_key, key)
     end
 
-    -- Initialize the count array 
     local count = {}
     for i = 1, (max_key - min_key + 1) do
         count[i] = 0
@@ -35,7 +32,6 @@ return function(
         count[i] = count[i] + count[i - 1]
     end
 
-    -- Build the output array (in stable order)
     local output = {}
     for i = #list, 1, -1 do
         local element = list[i]
@@ -44,7 +40,6 @@ return function(
         count[key - min_key + 1] = count[key - min_key + 1] - 1
     end
 
-    -- Copy the output array back to the original list
     for i, elem in ipairs(output) do
         list[i] = elem
     end