fix empty list validation and code data structures (#826)

* fix empty list validation and code data structures

* Update bucket_sort.py

#826 (review)

Author: nikolasvargas

sorts/bucket_sort.py

@@ -14,34 +14,22 @@
 #  Best Case O(n); Average Case O(n); Worst Case O(n)
 
 DEFAULT_BUCKET_SIZE=5
-def bucket_sort(my_list,bucket_size=DEFAULT_BUCKET_SIZE):
-    if(my_list==0):
-        print("you don't have any elements in array!")
 
+def bucket_sort(my_list, bucket_size=DEFAULT_BUCKET_SIZE):
+    if len(my_list) == 0:
+        raise Exception("Please add some elements in the array.")
 
-    min_value=min(my_list)
-    max_value=max(my_list)
+    min_value, max_value = (min(my_list), max(my_list))
+    bucket_count = ((max_value - min_value) // bucket_size + 1)
+    buckets = [[] for _ in range(int(bucket_count))]
 
-    bucket_count=(max_value-min_value)//bucket_size+1
-    buckets=[]
-    for i in range(bucket_count):
-        buckets.append([])
     for i in range(len(my_list)):
-        buckets[(my_list[i]-min_value)//bucket_size].append(my_list[i])
+        buckets[int((my_list[i] - min_value) // bucket_size)].append(my_list[i])
 
+    return sorted([buckets[i][j] for i in range(len(buckets))
+                                 for j in range(len(buckets[i]))])
 
-    sorted_array=[]
-    for i in range(len(buckets)):
-        buckets[i].sort()
-        for j in range(len(buckets[i])):
-            sorted_array.append(buckets[i][j])
-    return sorted_array
-
-
-
-
-#test
-#best on python 3.7.3
-user_input =input('Enter numbers separated by a comma:').strip()
-unsorted =[int(item) for item in user_input.split(',')]
-print(bucket_sort(unsorted))
+if __name__ == "__main__":
+    user_input = input('Enter numbers separated by a comma:').strip()
+    unsorted = [float(n) for n in user_input.split(',') if len(user_input) > 0]
+    print(bucket_sort(unsorted))